CARBOXAMIDE COMPOUNDS, COMPOSITIONS, AND METHODS FOR INHIBITING PARP ACTIVITY

Abstract: A compound of formula (I) or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherein: Y represents the atoms necessary to form a fused 5-to 6-membered, aromatic or non-aromatic, carbocyclic or N-containing heterocyclic ring, wherein Y and any heteroatom(s) therein are unsubstituted or independently substituted by at least one non-interfering alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-position of ring Y and is -COOR5 or a substituted or unsubstituted moiety selected from the group consisting of (a), (b), (c), (d), (e), (f) and (g) wherein R7 is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R1 is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R2, R3, R4 and R5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, or aryl, and are either unsubtsituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, amino, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, imino, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl and aryl.

Description: CARBOXAMIDE COMPOUNDS, COMPOSITIONS, AND METHODS FOR INHIBITING PARP ACTIVITY BACKGROUND OF THE INVENTION . Field of the Invention The present invention relates to inhibitors cf the nucleic enzyme poly (adenosine 5 ' -diphospho-rioose) polymerase ["poly (ADP-πOose) polymerase" or "PARP", which is also sometimes called "P^RS" for poly (ADP-πbose) syntnetasej . More particularly, the invention relates to the use of PARP inhibitors to prevent and/or treat tissue damage resulting from cell damage or death due to necrosis or apoptosis; neural tissue damage resulting from ischemia and reperfusion l'- ~ _r , ; neurological disorders and diseases; to prevent or treat vascular stroke; to treat or prevent cardiovascular disorders; to treat other conditions and/or disorders such as age-related macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cachexia, cancer, degenerative diseases of skeletal muscle involving replicative senescence, αiaoetes, head trauma, immune senescence, inflammatory bowel disorders (such as colitis and Crohn ' s disease), muscular dystrophy, osteoarthritis, osteoporosis, chronic and acute pain (such as neuropathic pain) , renal failure, retinal scnemia, seotic shock; isuch as endotoxic shock), ana skin aging; to extend the lifespan and proliferative capacity of cells; to alter gene expression of senescent cells; or to radiosensitize hypoxic tumor cells. 2. Description of the Prior Art Poly (ADP-πbose) polymerase ("PARP") is an enzyme located in the nuclei of cells of various organs, including muscle, heart and brain cells. PARP plays a physiological role in the repair of strand oreaks m DNA. Once activated by damaged DNA fragments, PARP catalyzes the attachment of up to 100 ADP-nbose units to a variety of nuclear proteins, mending histones and PARP itself. While the exact range of functions of PARP has not been fully established, this enzyme is trought to play a role in enhancing DNA repair. During major cellular stresses, however, the extensive activation of PARP can rapidly lead to cell damage or death through depletion of energy stores. Four molecules of ATP are consumeα for every molecule of NAD (the source of ADP- πbose) regenerated. Thus, NAD, the substrate of PARP, is depleted by massive PARP activation and, in the efforts to re-synthesize NAD, ATP may also be depleted. It has been reported that PARP activation plays a key role _n both NMDA- and NO-mduced neurotoxicity, as shown by the ise of PARP inhibitors to prevent such toxicity in cort_cal cultures m proportion to tneir potencies as inhibitors cf this enzyme (Zhang et al., "Nitric Oxide Activation of Poly (ADP-Ribose) Synthetase m Neurotoxicity", Science, 263 : 681 -89 (1994)); and m hippocampal slices (Wall s et al., "Neuroprotection Against Nitric Oxide Injury with Inhibitors of ADP-Ribosylat on" , NeuroRepor t , 5:3, 245- 48 1993)). The potential role of PARP inhibitors in treat_ng neurodegenerative diseases and head trauma nas thus been -cnown . Research, however, continues to pinpoint the exact mechanisms of their salutary effect in cerebral lscnerria, (Enαres et al., "Iscnemic Brain Injury _s Mediated by the Activation of Poly (ADP-Rioose) Polymerase" , J. Cereb . Blood Flow Metabol . , 17:1143-51 (1997)) ana m traumatic brain injury (Wallis et al., "Traumatic Neuroprotection with Inhibitors of Nitric Oxide and ADP-Ribosylation, Brain Res . , 710:169-77 (1996) ) . It has been demonstrated that single injections of PARP mhiD tors have reduced the infarct size caused by iscnemia and reperfusion of the heart or skeletal muscle m rabbits. In tnese studies, a single injection of the PARP inhibitor, 3-amιno-benzamιde (10 mg/kg), either one minute before occlusion or one minute before reperfusion, caused similar reductions m infarct size m the heart (32-42%) . Another PARP inhibitor, 1, 5-αιhydroxyιsoquιnolιne (1 mg/kg), reduced infarct size by a comparable degree (38-48%) . Thiemermann et al., "Inhibition of the Activity of Poly(ADP Ribose) Synthetase Reduces Ischemia-Reperfusion Injury m the Heart and Skeletal Muscle", Proc . Natl . Acad. Sci . USA, 94:679-83 (1997) . This finding has suggested that PARP inhibitors mignt be able to salvage previously ischemic heart or skeletal muscle tissue. PARP activation has also been shown to provide an index of damage following neurotoxic insults by glutamate (via NMDA receptor stimulation), reactive oxygen intermediates, amyloid β-protem, n-methyl-4-phenyl-l, 2, 3, 6-tetrahydropyrιdιne (MPTP '1 and its active metabolite N-methyl-4-phenylpyrιdιne (MPP , which participate in pathological conditions sucn as stroke, Alzheimer's disease and Parkinson's disease. Zhang et a^., "Poly (ADP-Ribose) Synthetase Activation: An Early Indicator of Neurotoxic DNA Damage", J. Neurochem. , 65: 3 , 1411-14 (1995). Other studies have continued to explore the role of PARP activation n cerebellar granule cells m vitro and m MPTP neurotoxicity. Cosi et al., "Poly (ADP-Ribose) Polymerase (PARP) Revisited. A New Role for an Old Enzyme: PARP Involvement in Neurodegeneration and PARP Inhibitors as Possmle Neuroprotective Agents", Ann. N. Y. Acad. Sci . , 825:366-79 ιl997); and Cosi et al., "Poly (ADP-R_oose) Polymerase Inhibitors Protect Against MPTP-mduced Depletions of Stπatal Dopamme and Cortical Noradrenaline m C57B1/6 Mice", Brain Res . , 729:264-69 (1996). Neural damage following stroke and other neurooegenerative processes is thought to result from a massive release of the excitatory neurotransmitter glutamate, which acts upon the N-methyl-D-aspartate (NMDA) receptors and other subtype receptors. Glutamate serves as the predominate excitatory neurotransmitter in the central nervous system (CNS) . Neurons release glutamate in great quantities when they are deprived of oxygen, as may occur during an ischemic bram insult such as a stroke or heart attac . This excess release of glutamate m turn causes over-stimulation (excitotoxicity) of N-methyl-D-aspartate (NMDA), AMPA, Kamate and MGR receptors. When glutamate binαs to these receptors, ion channels in the receptors open, permitting flows of ions across their cell membranes, e.g., Ca 2+ and Na + into the cells and K + out of the cells. These flows of ions, especially the influx of Ca 2+ , cause overstimulation of the neurons. The over-stimulated neurons secrete more glutamate, creating a feedback loop or domino effect which ultimately results in cell damage or death via the oroduction of proteases, lipases and free radicals. Excessive activation of glutamate receptors has been lmpl-cated m various neurological diseases and co n ditions _nc_^amg epilepsy, stroκe, Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis (ALS) , Huntxngton' s disease, schizophrenia, chronic pam, ischemia and neuronal loss following nypoxia, hypoglycemia, ischemia, trauma, and nervous insult. Recent studies nave also advanced a glutamatergic basis for compulsive disorders, particularly drug dependence. Evidence includes findings m many animal species, as well as, in cerebral cortical cultures treated with glutamate or NMDA, that glutamate receptor antagonists blocκ neural damage following vascαiar stroke. Dawson et a_ι_ . , "Protection of the Bram from Ischemia", Cerebrovascular Disease, 319-25 (H. Hunt Bat er ed., 1997). Attempts to prevent excitotoxicity by blocking NMDA, AMPA, Kamate and MGR receptors have proven difficult because each receptor has multiple sites to which glutamate may bind. Many of the compositions that are effective m Clocking the receptors are also toxic to animals. As such, there is no known effective treatment for glutamate abnormalities. The stimulation of NMDA receptors, in turn, activates the enzyme neuronal nitric oxide synthase (NNOS), which causes the formation of nitric oxide (NO) , which more directly mediates neurotoxicity. Protection against NMDA neurotoxicity has occurred following treatment with NOS mhicitors. See Dawson et al., "Nitric Oxide Mediates Glutamate Neurotoxicity m Primary Cortical Cultures", Proc . Natl . Acad. Sci . USA, 88 : 6368 -1 1 (1991); and Dawson et al., "Mechanisms of Nitric Oxide-mediated Neurotoxicity in Primary Bram Cultures", J. Neurosci . , 13 : 6 , 2651-61 (1993). Protection against NMDA neurotoxicity can also occur m cort_cal cultures from mice with targeted disruption of NNOS . See Dawson et al., "Resistance to Neurotoxicity Cortical Cultures from Neuronal Nitric Oxide Synthase-Deflcient Mice", J. Neurosci . , 16: 8 , 2479-87 (1996). It is known that neural damage following vascular stroke is markedly diminished in animals treated with NOS inhibitors or m mice with NNOS gene disruption. Iadecola, "Bright and Dar ≤^des cf Nitric Oxide m Ischemic Bram Injury", Trends Neurosci . , 20 : 3 , 132-39 ( 1997); and Huang et al., "Effects of Cereoral Ischemia in Mice Deficient in Neuronal Nitric Oxide Synthase", Science, 265: 1883-85 (1994). See also, Beck an et al., "Pathological Implications of Nitric Oxide, Superoxide and Peroxynitπte Formation", Biochem. Soc . Trans . , 22:330-34 (1993). Either NO or peroxynitπte can cause DNA damage, which activates PARP. Further support for this is provided in Szabo et al . , "DNA Strand Breakage, Activation of -DP-Ribose) Synthetase, and Cellular Energy Dec_etιon are I n volved m the Cytotoxicity in Macrophages and Smooth Muscle Cells Exposed to Peroxynitπte" , Proc . Natl . Acad. Sci . USA, 53:1753-58 (1996). Zhang et al., U.S. Patent No. 5,587,384 issued December 24, 1996, discusses the use of certain PARP inhibitors, such as benzamide and 1, 5-dιhydroxy-ιsoqumolme, to prevent NMDA- mediated neurotoxicity and, thus, treat stroke, Alzheimer's disease, Parkinson's disease and Huntmgton's disease. However, it is has now been discovered that Zhang et al. may have oeen in error in classifying neurotoxicity as NMDA- mediated neurotoxicity. Rather, it may have been more appropriate to classify the m vivo neurotoxicity present as glutamate neurotoxicity. See Zhang et al . "Nitric Oxide Activation of Poly (ADP-Ribose) Synthetase Neurotoxicity", Science, 263 : 681 -89 (1994). See also, Cosi et al., Poly(ADP- Ribose) Polymerase Inhibitors Protect Against MPTP-mduced Depletions of Striatal Dopamme and Cortical Noradrenaline m C57B1/6 Mice", Brain Res . , 729:264-69 (1996). It is also known that PARP inhibitors affect DNA repair generally. Cristovao et al., "Effect of a Poly (ADP-Ribose) Polymerase Inhibitor on DNA Breakage and Cytotoxicity Induced by Hydrogen Peroxide and γ-Radιatιon, " Terato . , Carcino . , and Muta . , 16:219-27 (1996), discusses the effect of hydrogen peroxide and γ-radiation on DNA strand breaks in the presence of arc the absence of 3-ammobenzam ^ de, a potent mnibitor of PARP. Cristovao et al . observed a PARP-oependent recovery of DNA strand breaks in leukocytes treated with hydrogen peroxide . PARP inhibitors have been reported to be effective m radiosensitizmg hypoxic tumor cells and effective in prevertmg tumor cells from recovering from potentially lethal damage of DNA after radiation therapy, presumably by their ability to prevent DNA repair. See U.S. Patent Nos. 5,032,617; 5,215,738; and 5,041,653. Evidence also exists that PARP inhibitors are userul for treatmg inflammatory bowel disorders. Salzman et al., "Role of Peroxynitrite and Poly (ADP-Ribose) Synthase Activation Experimental Colitis," Japanese J. Pharm. , 75, Supp. 1:15 ( 1991 discusses the ability of PARP inhibitors to prevent or treat colitis. Colitis was induced rats by mtralummal administration of the hapten trmitrobenzene sulfomc acid in 50% ethanol. Treated rats received 3- ammobenzamide, a specific inhibitor of PARP activity. Inhibition of PARP activity reduced the inflammatory response and restored the morphology and the energetic status of the dista- colon. See also, Southan et al., "Spontaneous Rearrangement of Ami no a 1 ky 1 I t hi our e a s into Mercaptoalkylguanid es, a Novel Class of Nitric Oxide Synthase Inhibitors witn Selectivity Towards the Inαucible Isoform", Br. J. Pharm. , 117:619-32 (1996); and Szabo et al., "Mercaptoethylguamdme and Guanidine Inhibitors of Nitric Oxiαe Synthase React with Peroxynitrite and Protect Against Peroxynitπte-mduced Oxidative Damage", J. Biol . Chem. , 272: 9030-36 (1997) . Evidence also exists that PARP inhibitors are useful for treating arthritis. Szabo et al., "Protective Effects of an Inhibitor of Poly (ADP-Ribose) Synthetase m Collagen-Induced Arthritis," Japanese J. Pharm. , 75, Supp. 1:102 (1997), discusses the ability of PARP inhiDitors to prevent or treat collagen-mαuced arthritis. See also Szabo et al., "DNA Stra-d Breakage, Activation of Poly (ADP-Ribose) Synthetase, and Cellular Energy Depletion are Involved m the Cytotoxicity in Macrophages and Smooth Muscle Cells Exposed to Peroxynitrite," Proc . Natl . Acad. Sci . USA, 93 : l ~] 53 - 58 (Marcn 1996); Bauer et al., "Modification of Growth Related Enzymatic Pathways and Apparent Loss of Tumoπgenicity of a ras-transformed Bovine Endothelial Cell Line by Treatment with 5-Iodo-β-amιno-l, 2-benzopyrone (INH 2 BP)", Intl . J. Oncol . , 8:239-52 (1996); and Hughes et al., "Induction of T Helper Cell hyporesponsiveness m an Experimental Model of Autcimmunity by Using Nonmitogenic Antι-CD3 Monoclonal Ant oody", J. Immune , 153 : 3319-25 (1994). Further, PARP inhibitors appear to oe useful for treating diabetes. Heller et al., "Inact±vation of the Poly (ADP-Ribose) Polymerase Gene Affects Oxygen Radical and Nitric Oxide Toxicity in Islet Cells," J. Biol . Chem. , 270:19, 11176-80 (May 1995), discusses the tendency of PARP to deplete cellular NAD+ and induce tne death of msulin- produc g islet cells. Heller et al. used cells from mice with inactivated PARP genes and found that these mutant cells did not show NAD+ depletion after exposure to DNA-αamagmg radicals. The mutant cells were also found to be more resistant to the toxicity of NO. Further still, PARP inhibitors have been shown to be useful for treating endotoxic shock or septic shock. Zmgarelli et al., "Protective Effects of Nicotmamide Against Nitric Oxioe-Mediated Delayed Vascular Failure in Endotoxic Shock: Potential Involvement of PolyADP Ribosyl Synthetase," Shock, 5:258-64 (1996), suggests that inhibition of tne DNA repair cycle triggered by poly(ADP πbose) synthetase has protective effects against vascular failure in endotoxic shoc . Zmgarelli et al. found that nicotmamide protects against delayed, NO-mediated vascular failure in endotoxic shock. Zmgarelli et al. also found that the actions of nicotmamide may be related to inhibition of the NO-meαiated activation of tne energy-consuming DNA repair cycm, triggered b\ poly (ADP πbose) synthetase. See also, Cuzzocrea, "Role of Peroxynitrite and Activation of Poιy(ADP- Ribose) Synthetase in the Vascular Failure Induced by Zymosan-activated Plasma," Brit . J. Pharm. , 122:493-503 (1997) . Yet anotner known use for PARP inhibitors is treating cancer. Suto et al., "Dihydroisoqumolmones : The Design and Synthesis of a New Series of Potent Inhibitors of Poly (ADP-Ribose) Polymerase", Anticancer Drug Des . , 7:107-17 (1991 , discloses processes for synthesizing a numper of different PAR? mnipitors . In addition, Suto et a . , U.S. Patent No. 5,177,075, discusses several isoqumolmes used for enhancing the lethal effects of ionizing radiation or chemotherapeutic agents on tumor cells. eltin et al., "Effect of 6 (5Jf) -Phenanthridmone, an Inhibitor of Poly(ADP- πbose) Polymerase, on Cultured Tumor Cells", Oncol . Res . , 6:9, 399-403 (1994), discusses the inhibition of PARP activity, reduced proliferation of tumor cells, and a marked synergistic effect when tumor cells are co-treateα with an alkylating drug. Still another use for PARP inhibitors is the treatment of peripherax nerve injuries, and the resultant pathological pam syndrome known as neuropathic pam, such as that induced by chronic constriction injury (CCI) of the common sciatic nerve and in which transsynaptic alteration of spmal cord αorsal horn characterized by hyperchromatosis of cytoplasm and nucleoplasm (so-called "dark" neurons) occurs. See Mao et al., Pain, 72:355-366 (1997). PARP inhibitors have also been used to extend the lifespan and proliferative capacity of cells including treatment of diseases such as skin aging, Alzheimer's αisease, atherosclerosis, osteoarthritis, osteoporosis, muscular dystrophy, degenerative diseases of skeletal muscle involving replicative senescence, age-related macular degeneration, immune senescence, AIDS, and other immune senescence diseases; ana to alter gene expression of senescent cells. See WO 98/27975. Large numbers of known PARP inhibitors have been described m Banasik et al., "Specific Inhibitors of Poly (ADP-Ribose) Synthetase and Mono (ADP-Ribosyl) - Transferase", J. Biol . Chem. , 267: 3 , 1569-75 (1992), and in Banasik et al., "Inhibitors and Activators of ADP- Ribosylation Reactions", Molec . Cell . Biochem. , 138 : 185- 91 (1994) . However, the approach of using these PARP inhibitors m the ways discussed above has been limited effect. For example, side effects have been observed with some of the best-known PARP inhibitors, as discussed m Milam et al., "Inhibitors of Poly (Adenosine Diphosphate-Ribose) Synthesis: Effect on Other Metabolic Processes", Science, 223 : 589-91 (1984). Specifically, the PARP inhibitors 3-aminobenzamide and benzamide not only inhibited the action of PARP but also were shown to affect cell viability, glucose metabolism, and DNA synthesis. Thus, it was concluded that the usefulness of these PARP inhibitors may be severely restricted by the difficulty of finding a dose that will inhibit the enzyme without producing additional metabolic effects. Huff et al. discloses a process for the stereo- controlled synthesis of cis-decahydroιsoqumolme-3- carcoxylic acids. Huff et al . , U.S. Patent No. 5,338,851, issued August 16, 1994. The compounds m Huff et al . are taugnt to be useful in the synthesis of NMDA excitatory ammo acic receptor antagonists, which can have a neuroprotective effect. Ornste discloses decahydroιsoqumolme-3-carboxylιc aciαs as antagonists of NMDA ammo acid receptors. Ornstem, "Excitatory Ammo Acid Receptor Antagonists", U.S. Patent No. 4,902,695, issued February 20, 1990. Examples include decahydro-6- [1 (2) H-tetrazol-5-ylmethyl] - 3 - isoα.inolinecarboxylic acid, 3-carboxydecahydro-6- acid, and decahydro-6- (phosphonomethyl) -3- lsoouinolmecarboxylic acid. These compounds are said to be usef__ for treating a variety of disorαers including neurological disorders, stroke, cerebral ischemia and others . Further, many multicyclic carboxamide compounds other than the compounds of the invention are known: I. N-{ [methoxy-5- (trifluoromethyl) -1-naphthalenyll - carbonyl} -N- [ (ethoxy) carbonyl] glycine, shown in Sestanj et al., U.S. Patent No. 4,925,968, issued May 15, 1990. The N- acyι-\-naphthoylglycmes of Sestanj et al. are said to be usefu. for treating diabetes mellitus and complications thereof, such as neuropathy, nephropathy, retinopathy and cataracts . II. 4-bromo-N- { 2- [ - (2 , 3 -di chloropheny1 -1- piperazmylj ethyl} -1-methoxy-2-naphthalenecarboxamide, snown in G_ase et al., U.S. Patent No. 5,395,835, issued March 7, 1995. Glase et al. discloses compounds having the formula: These compounds are disclosed as dopammergic agents useful for treating, for example, psychotic depression, suostance abuse and compulsive disorders. Ill . 7 -methoxy- 1- ( 1-methylethoxy) -2-naphthalene- carooxamide, shown in Boschelli et al . , U.S. Patent No. 5,434,188, issued July 18, 1995. Boschelli et al . discloses naphthalene carboxamides having the structure: where X is 0 or S(0) n . IV. N,N-dιmethyl-3-methyl-2-α-naphthyl pentanamide, sno/- m Ξber^e et ai., U.S. Patent No. 3,5^3,304, msued March 30, 1971. Eoeπe et ai. discloses compounds having the formula : where X is a carbonyl or methylene radical. These compounds are used to prevent the adhesion of leuKocytes to endothelial cells. Indications are said to include the treatment of AIDS, rheumatoid arthritis, osteoarthritis, asthma, psoriasis, resoxratory distress syndrome, reperfusior mjury, ischemia, αlcerative colitis, vasculaditis, atherosclerosis, inflammatory dowel disease and tumor metastasis. V. l-benzoyl-3-methyl-7-nιtronaphthalene and 1-benzoyl- 2-methyl-6-nιtronaphthalene, shown m Witzel, U.S. Patent No. 3,899,529, issued August 12, 1975. Witzel discloses aroyl- substituted naphthalene acetic acid compounds having the formula : - H where X, Y and M can each be an ammo group. These compounds are said to be useful for treating fever, pam and inflammation . VI. (1, 1 ' -bιphenyl-4-yl) -4-qumazolmecarboxylιc acid, snown m Hesson, U.S. Patent No. 4,639,454, issued January 2", 198 7 . Hesson discloses qumazolme-4-carboxyιιc acid navmα f"e icrmαla: The Hesson compounds are said to have a tumor-mhibitmg effec . It is not believed that the above disclosed compounds have been shown to inhibit PARP activity per se. SUMMARY OF THE INVENTION The present mvention is directed to compounds navmg the following formula I : I or pharmaceutically acceptable salt, hyorate, ester, solvate, proαrug, metaoolite, stereoisomer, or mixtures thereof; wherem: - represents the atoms necessary to form a fusee 5- to 6-membered, aromatic or non-aromatic, caroocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non- lnterfering alkyl, alkenyl, cycloalkyl, cycxoalkenyi, aralkyl, aryl, cardoxy or halo substituent; \ is at the 1-posιtιon of ring Y and is -COOR 5 or a suostituted or unsubstituted moiety selected from the group consisting of and where-' is hydrogen, alkyl, alkenyl, cycloalk l or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R x is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyx, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdme, or 1-ιmιdazoIme, and are either unsuPstituted or substituted with a moiety selectee from tne group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, am o, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl; provided that, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. A particularly preferred embodiment of the invention has formula II : II or a pharmaceutically acceptaole salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: ~ and B are independently carbon or nmrogen and are optionally and independently unsuostituted or substituted with an alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl or aryl group; , R l r R 2 , R 3 and R 4 are oefmed above; and R 6 and any supstituent (s) on A and B are themselves optionally and independently sαostituted by, without limitation, alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryi, haio, haloalkyl, trifluoromethyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, and/or 1-ιmιdazoιme; provided that at least one of A and B is nitrogen. In another embodiment, a process for making the compound of formula I comprises the step of contacting an intermediate of formula III: III wit- a -COOR 5 radical or a substituted or unsubstituted compound selected from the group consisting of: and wnerem R l r R 2 , R 3 , R 4 , R 5 , R 7 and Y are as defined in above; and "halo" is a chloro, bromo or lodo moiety. In yet another embodiment, the pharmaceutical composition of the invention comprises a pharmaceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: represents tne atoms necessary to form a fused 5- to 6-mempered, aromatic or non-aromatic, carpocyclic or N-ccntainmg heterocyclic ring, wπerem i and any heteroatom ( s) therein are unsubstituted or independently substituted with at least one non- terfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X s at the 1-posιtιon of ring Y ano is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wnerem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkvl, aiκenyl, cycloalκyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , and R 4 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdιne, or 1- lmidazolme, and are themselves either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carooxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, ritπlo, thio, thiocarbonyl, sulfhydryl, halo, haioalkyl, trifluoromethyl, aralkyl and aryl; provided that, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. In a still further embodiment of the invention, the pharmaceutical composition of the invention comprises a pharmaceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, and a pharmaceutically acceptable carrier, wherem the compound of formula I is present m an amount that is sufficient to inhibit PARP activity, to treat or prevent tissue damage resulting from ce ^ l damage or death due to necrosis or apoptosis, to effect a neuronal activity not mediated by NMDA toxicity, to effect a neuronal activity mediated by NMDA toxicity, to treat neural tissue damage resulting from ischemia and reperfusion injury, neurological disorders and neurodegenerative diseases; to prevent or treat vascular stroke; to treat or prevent cardiovascular disorders; to treat other conditions and/or disorders such as age-related macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cachexia, cancer, degenerative diseases of skeletal muscle involving rep__catιve senescence, diabetes, head trauma, immune senescence, inflammatory bowel disorders (such as colitis and Croh"" ' s disease), muscular dystrophy, osteoarthritis, osteoporosis, chronic and/or acute pam (such as neuropathic pam;, renal failure, retinal ischemia, septic shock (such as endotoxic shock) , and skm aging; to extend the lifespan and proli erative capacity of cells; to alter gene expression of senescent cells; or to radiosensitize hypoxic tumor cells, and wherem: i represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-containing heterocyclic ring, wherem Y and any heteroatom ( s ) therein are unsubstituted or independently substituted with at least one non- mterfering alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or nalo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of , and , wherem R is hydrogen, alkyl, alkenyl, cycloalky_ or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 1 is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; ,, R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdme, or 1- lmidazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, tniocaroony _ , sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. In a particularly preferred embodiment of the composition, the compound is of formula II, as described above . In an additional embodiment, a method of inhibiting PARP activity comprises administering a compound of formula I, as described above for the pharmaceutical compositions of the invention. In yet further embodiments, the amount of the compound administered in the methods of the invention is sufficient for treating tissue damage resulting from cell damage or death due to necrosis or apoptosis, neural tissue damage resulting from ischemia and reperfusion injury, or neurological disorders and neurodegenerative diseases; to prevent or treat vascular stroke; to treat or prevent cardiovascular disorders; to treat other conditions and/or disorders such as age-related macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cacnexia, cancer, degenerative diseases of skeletal muscle involving replicative senescence, diabetes, head trauma, immure senescence, inflammatory bowel disorders (such as colitis and Crohn ' s disease), muscular dystrophy, osteoarthritis, osteoporosis, chronic and/or acute pam (such as neuropathic pain) , renal failure, retinal ischemia, septic sncc< (such as endotoxic shock), and skin aging; to extend the mfes an and proliferative capacity of cells; to alter gene expression of senescent cells; or to radiosensitize hypoxic tumor cells. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the distribution of the cross-sectional infarct area at representative levels along the rostrocaudal axis, as measured from the mteraural line m non-treated animals and m animals treated with 10 mg/kg of 3,4-dιhydro- 5- [4- ' 1-piperidinyl) -butoxyl] -1 (2H) -isoquinolmone . Figure 2 shows the effect of intraperitoneal administration of 3, 4-dihydro-5- [4- (1-pιperιdmyl) -butoxy] - l(2H , -ιsoαuιnolmone on the infarct volume. DETAILED DESCRIPTION OF THE INVENTION The carboxamide compounds of the present invention inhibit PARP activity. As such, they may treat or prevent neural tissue damage resulting from cell damage or death due to necrosis or apoptosis, cerebral ischemia and reperfusion injury or neurodegenerative diseases in an animal; they may extend the lifespan and proliferative capacity of cells and thus oe used to treat or prevent diseases associated therewith; they may alter gene expression of senescent cells; and they may radiosensitize hypoxic tumor cells. Preferably, the ccmpounαs of the invention treat or prevent tissue damage resulting from cell damage or death due to necrosis or apoptosis, and/or effect neuronal activity, either mediated or not mediated by NMDA toxicity. These compounds are thought to interfere with more than the glutamate neurotoxicity and NO-mediated biological pathways. Further, the compounds of the invention can treat or prevent other tissue damage related to PARP activation. For example, the compounds of the invention can treat or prevent cardiovascular tissue damage resulting from cardiac ische m ia or reperfusion injury. Reperfusion injury, for xnsta-ce, occurs at the termination of carαiac oypass proceαures or during cardiac arrest when the neart, once preve n ted from receiving blood, begins to reperfuse. The compounds of the present invention can also be used to extend or increase the lifespan or proliferation of cells and thus to treat or prevent diseases associated therewith and induced or exacerbated by cellular senescence including skm aging, atherosclerosis, osteoarthritis, osteoporosis, muscular dystrophy, degenerative diseases of skeletal muscle involving replicative senescence, age-related macular degeneration, immune senescence, AIDS and other ^mrnune senescence diseases, and other diseases associated with cellular senescence and aging, as well as to alter the gene expression of senescent cells. These compounds can also be used to treat cancer and to radiosensitize hypoxic tumor cells to render the tumor cells more susceptible to radiation therapy and to prevent the tumor cells from recovering from potentially lethal damage of DNA after radiation therapy, presumably by their ability to prevent DNA repair. The compounds of the present invention can be used to prevent or treat vascular stroke; to treat or prevent cardiovascular disorders; to treat other conditions and/or disorders such as age-related macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cacnexia, cancer, degenerative diseases of skeletal muscle involving replicative senescence, diabetes, head trauma, immune senescence, inflammatory bowel disorders (such as colitis and Crohn's disease), muscular dystrophy, osteoarthritis, osteoporosis, chronic and/or acute pam (such as neuropathic pair , renal failure, retinal ischemia, septic shock v such as endotoxic shock), and skm aging. Preferably, the compounds of the invention act as PARP inhibitors to treat or prevent tissue damage resulting from cell death or damage αue to necrosis or apoptosis; to treat or prevent neural tissue damage resulting from cerebral ischemia and reperfusion injury or neurodegenerative αiseases m ar anima^; to extend and increase the lifespan and proliferative capacity of cells; to alter gene expression of senescent cells; and to radiosensitize tumor cells. These compounds are thought to interfere with more than the NMDA- neurotoxicity and NO-mediated oiological pathways. Preferably, the compounds of the invention exhibit an IC 50 for inhibiting PARP m vitro of about 100 μM or lower, more preferably, about 25 μM or lower. As used herein, the term "cardiovascular disorders" refers to those disorders that can either cause ischemia or are caused cy reperfusion of the heart. Examples mciude, but are not limited to, coronary artery disease, angina pectoπs, myocardial infarction, cardiovascular tissue damage caused by cardiac arrest, cardiovascular tissue damage caused by cardiac bypass, cardiogenic shock, and related conditions that would be known by those of ordinary skill in the art or which involve dysfunction of or tissue damage to the heart or vasculature, especially, but not limited to, tissue damage related to PARP activation. The term "ischemia" refers to localized tissue anemia due to obstruction of the inflow of arterial blood. Global ischemia occurs when blood flow to the entire brain ceases for a period of time. Global iscnemia may result from cardiac arrest. Focal ischemia occurs when a portion of the bram is deprived of its normal blood supply. Focal ischemia may result from thromboembolytic occlusion of a cerePral vessel, traumatic head injury, edema or bram tumor. Even if transient, both global and focal ischemia can cause widespread neuronal damage. Although nerve tissue damage occurs over nours or even days following the onset of ischemia, some permanent nerve tissue damage may develop in the mitial minutes following the cessation of blood flow to the oram. Much of this damage has been attributed to glutamate toxicity and to the secondary consequences of tissue reperfusion, such as the release of vasoactive products by damaged endothelium and the release of cytotoxic products, sucn as free radicals and leukotrmes, c_ Ϋ the damaged tissue. Ischemia can also occur m the heart m myocardial infarction and other cardiovascular disorders in which the coronary arteries have been obstructed as a result of atherosclerosis, thrombi, or spasm. The term "neural tissue damage resulting from ischemia and reperfusion injury and neurodegenerative diseases" includes neurotoxicity, such as seen in vascular stroke and globa ^ and focal ischemia. The term "neurodegenerative diseases" includes Alzheimer's disease, Parkinson's disease and Huntmαton's disease. The term "nervous insult" refers to any damage to nervous tissue and any disability or death resulting therefrom. The cause of nervous insult may be metabolic, toxic, neurotoxic, latrogenic, thermal or chemical, and includes without limitation, ischemia, hypoxia, cereorovascular accident, trauma, surgery, pressure, mass effect, hemorrhage, radiation, vasospasm, neurodegenerative disease, infection, Parkinson's disease, amyotrophic lateral sclerosis (ALS), myelmation/demyelmation process, epilepsy, cognitive disorder, glutamate abnormality and secondary effects thereof. The term "nervous tissue" refers to the various components that make up the nervous system including, without limitation, neurons, neural support cells, glia, Schwann cells, vasculature contained withm and supplying these structures, the central nervous system, the Pram, the bram stem, the spmal cord, the junction of the central nervous system with the peripheral nervous system, the peripheral nervous system, and allied structures. The term "neuroprotective" refers to tne effect of reducing, arresting or ameliorating nervous insult, and protecting, resuscitating, or reviving nervous tissue that has suffered nervous insult. The term "preventing neurodegeneration" includes the aoι__cy to prevent neurodegeneration in patients diagnosed as having a neurodegenerative disease or who are at risk of deve.opmg a neurodegenerative disease. The term also encompasses preventing further neurodegeneration in patients who are already suffering from or have symptoms of a neurodegenerative disease. The term "treating" refers to: i) preventing a disease, disorder or condition from occurring m an animal that may be predisposed to the disease, disorder and/or condition, but has not yet been diagnosed as having it; (n) inhibiting the disease, disorder or condition, i.e., arresting its development; and Uii) relieving the disease, disorder or condition, i.e., causing regression of the disease, disorder and/or condition . The term "cancer" is interpreted broadly. The compounds of tne present invention can be "anti-cancer agents", which term also encompasses "anti-tumor cell growth agents" and "anti-neoplastic agents". The term "isomers" refer to compounds having the same number and kind of atoms, and hence, the same molecular weight, but differing m respect to the arrangement or conmσuratic" of the atoms. "Stereoisomers" are isomers that differ only in the arrangement of atoms in space. "Enantiomers" are a pair of stereoisomers that are non- supeπmposable mirror images of each other. "Diastereoisomers" are stereoisomers which are not mirror images of each other. "Racemic mixture" means a mixture containing equal, or roughly equal, parts of individual enantiomers. A "non-racemic mixture" is a mixture containing unequal, or substantially unequal, parts of individual enantiomers or stereoisomers. ^he term "radiosensitizer", as used herein, is defined as a molecule, preferably a low molecular weight mo.ecule, admi n istered to animals in therapeutxcally effective amounts to mcrease the sensitivity of the cells to be radiosensitized to electromagnetic radiation and/or to promote the treatment of diseases which are treatabxe with electromagnetic radiation. Diseases which are treatable with electromagnetic radiation include neoplastic diseases, benign and malignant tumors, and cancerous cells. Electromagnetic radiation treatment of other diseases not listed herein are also contemplated by the present mvention. The terms "electromagnetic radiation" and "radiation" as used herein memoes, but is not limited to, radiation havmg the wave_enσth or 10 " to 10 meters. Preferred embodiments of the present mvention employ the electromagnetic radiation of: gamma-raoiation (lO "2 to 10 " m) x-ray radiation 10 " to 10 "" m) , ultraviolet light (10 nm to 400 nm) , visible light (400 nm to 700 nm) , infrared radiation (700 nm to 1.0 mm), and microwave radiation (1 mm to 30 cm) . Radiosensitizers are known to increase the sensitivity of cancerous cells to the toxic effects of electromagnetic radiation. Several mechanisms for the mode of action of radiosensitizers have been suggested in the literature including: hypoxic cell radiosensitizers ( e.g., 2- nitrcimidazole compounds, and benzotriazme dioxide compounds) promote the reoxygenation of hypoxic tissue and/or catalyze the generation of damaging oxygen radicals; non- hypoxic cell radiosensitizers (e.g., halogenated pyπmidmes) can be analogs of DNA bases and preferentially incorporate mto the DNA of cancer cells and thereby promote the radiation-mduced breaking of DNA molecules and/or prevent the normal DNA repair mechanisms; and various other potential mecnanisms of action have been hypothesized for radiosensitizers m the treatment of disease. Many cancer treatment protocols currently employ radiosensitizers activated by the electromagnetic radiation of x-rays. Examples of x-ray activated radiosensitizers include, out are not limited to, the following: metronidazo e , misonidazole , desmethylmisonidazole, pimonioazole, etaniαazole, nimorazoie, mitomyc C, RSU 1069, SR 4233, E09, RB 6145, nicotmamide, 5-bromodeoxyurιdme (BUdR) , 5-ιododeoxyurιdme (lUdR), bromodeoxycytidme, fluorodeoxyuπdme (FudR), hydroxyurea, cisplatm, and therapeutically effective analogs and derivatives of the same . Photodynamic therapy (PDT) of cancers employs visible light as the radiation activator of the sensitizing agent. Examples of photodynamic radiosensitizers include the following, out are not limited to: hematoporphyrm derivatives, Pnotofrm, benzoporphyrm derivatives, NPe6, tin etioporphyπ- SnET2, pheoborbide-a, bacteπochloropnyll-a, naphthalocyanmes, phthalocyanmes, zinc phthalocyanme, and therapeutically effective analogs and derivatives of the same . Radiosensitizers may be administered in conjunction with a therapeutically effective amount of one or more other compounds, including but not limited to: compounds which promote the incorporation of radiosensitizers to the target cells; compounds which control the flow of therapeutics, nutrients, and/or oxygen to the target cells; chemotherapeutic agents which act on the tumor with or witnout additional radiation; or other tnerapeutically effective compounds for treating cancer or other disease. Examples of additional therapeutic agents that may be used m conjunction with radiosensitizers include, but are not limited to: 5-fluorouracil , leucovorin, 5 ' -ammo- 5 ' deoxythymidme, oxygen, carbogen, red cell transfusions, perfluorocarbons (e.g., Fluosol-DA) , 2,3-DPG, BW12C, calcium channel blockers, pentoxyfyllme, antiangiogenesis compounds, hydralazme, and L-BSO. Examples of chemotherapeutic agents that may be used in conjunction with radiosensitizers include, but are not limited to: adriamycin, camptotnecm, carboplatm, cisplatin, daunorubicm, docetaxel, doxoruoicm, mterferon (alpha, beta, gamma) , interleukin 2, irmocecan, pacl_taxel, topotecan, and therapeutically effective analogs arc derivatives of tne same. The inventors have now discovered that select carboxamide compounds can mhipit PARP activity a α can ameliorate tissue damage resulting from cell damage or death due to necrosis or apoptosis and/or neural tissue damage, including that following focal ischemia and reperfusion injury; can increase or extend the lifespan or proliferation of cells; can alter gene expression m senescent cells; and can radiosensitize tumor cells. Generally, inhibition of PARP activity spares the cell from energy mss, preventing irre v ersible depolarization of the neurons and, thus, provxdes neuroprotection. While not wishing to be pound thereoy, it is thought that PARP activation may olay a common role m still other excitotoxic mechanisms, perhaps as yet undiscovered, in addition to the production of free radicals and NO. Since PARP is necessary for DNA repair, the inhiDition of PARP can also be used to prevent radiation damaged tumor cells from recovering from potentially _ethal damage of DNA by preventing DNA repair. PARP inhibitors may also be used to extend or increase the lifespan and prol_feration of cells and to thus prevent or treat diseases and conditions associated with cellular senescence, and can be used to alter the gene expression of senescent cel_s. The compounds of the invention act as PARP inhibitors to treat or prevent tissue damage resulting from cell damage or death due to necrosis or apoptosis; to treat or prevent neural tissue damage resulting from cerebral iscnemia and reperfusion injury or neuro-degenerative diseases in a mammal; to extend and increase tne lifespan and proliferative capacity of cells; to alter gene expression of senescent cel_; and to radiosensitize tumor cells. These compounds are thought to interfere with more than the NMDA-neurotoxicity and NO-mediated biological pathways. Preferably, the compounds of the invention exhibit an IC S0 for inhibiting PARP _tro of aoout 100 μM or lower, more preferably, about 25 μM or lower. Tne compound of the mvention has formu_a I: I or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer , or mixtures thereof, wherem Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, caroocyclic or '.-containing heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfering alkyl, allenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent. When Y forms a fused 5-membered carbocyclic ring, examples thereof include such rings as fused cyclopentane, cycmpentene, cyclopentadiene and the like. When Y forms a 5-membered N-contammg heterocyclic ring, examples thereof include sucn rings as fused pyrrole, isopyrrole, lmidazole, _soι~ιdazo^e , pyrazole, pyrrolidine, pyrrolme, imidazolidme, imidazolme, pyrazolidme, pyrazolme and the luce rings. When Y forms a fused 6-memoered carbocyclic ring, examples thereof include such rings as fused cyclonexane, cyclonexene, benzene and the like. When Y forms a 6-membered N-cortammg heterocyclic ring, examples thereof include such rings as pyridine, pyrazme, pyrimidine, pyπαazine, pιper_dιne, piperazme, morpholme and the like rings. Y may be aromatic, such as pyrrole, benzene or pyridine, or non-aromatic such as cyclopentene, pipenoyl or piperazinyl . Specific examples of particularly useful Y structures are s'o n below: In a preferred embodiment, however, Y has at least one site of unsaturation . Even more preferably, Y forms a fused benzene ring. Y can be unsuostituted or substituted with one or more non-interfering substituents. For example, Y can be substituted with an alkyl group, such as methyl, ethyl, isopropyi, t-butyl, n-pentyl, 2-methylhexyl, αoαecyl, octadecyl and the like; with an alkenyl group, such as vinyl, ethenyi, isopropenyl, 2, 2-dιmethyl-i-propenyl, cecenyl, hexadecenyl and the like; with a cycloalkyl group, such as adamantyl, cyclobutyl, cyclohexyi, cycloheptyl, 3-methyl-l- cyclodecyl and the like; with a cycloalkenyl group, such as cyclopropenyl, cyclopentadienyi, cyclohexenyl, cyciooctenyl and the like; with an aralkyl group, such as benzyl, 3-(l)- naphthyl-1-propyl, methylbenzyl, ethylbenzyl, propylbenzyl, n-propylbenzyl, butylbenzyl, n-butyibenzyl, isobutyibenzyl, sec-butylbenzyl, tert-butylbenzyl and the like; or with an aryl group such as phenyl, naphthyl, anthracenyl, pyridinyl, thienyl and the like. The X group attached to the Y ring in formula I is attached at the 1-position. The "1-position" is defined as the non-shared ring position on the Y ring that is two careens away from the carbon attached to the amide group (on the adjacent non-Y ring) . The examples below further indicate what is meant by the "1-position": The X group may be a carboxylic acid (-COOH), a carboxylic acid analogue (-COOR 5 ) , or any useful carboxylic acid mimic. Examples of useful carboxylic acid mimics include : and wneren R alkyl, alkenyl, cycloalkyl, cycloalkenyl, D ara. or such as described above for substituents , R may also be either unsubstituted or substituted with one or more non-interfering substituents, such as the alkyl, alkenyl, cycloalkyl and cycloalkenyl groups described above. The above carboxylic acid mimics are shown in R. Silverman, 0 Tne Organi c Chemistry of Drug Design and Drug Action, Academic Press (1992) . Ri may be alkyl, alkenyl, cycloalkyl or cycloalkenyl group. Examples of useful alkyl groups include, without limitation, methyl, ethyl, propyl, butyl, pentyl, hexyl, 5 isopropyi, isobutyl, tert-butyl, n-pentyl, 2-methyIpentyI ana the like. Examples of useful alkenyl groups include, without limitation, ethenyl, propenyl, butenyl, pentenyl, 2- methylpentenyl and the like. Examples of useful cycloalkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, 0 adamantyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl and the like. Examples of useful cycloalkenyl groups include cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cycloctenyl, cyclononenyl, cyclodecenyl and the like. R l may itself be unsubstituted or substituted with one or more 5 additional alkyl, alkenyl, cycloalkyl or cycloalkenyl groups. R 3 , and R s are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl or aralkyl, as described above. Additionally, R 2 , R 3 , R 4 and R 5 can be an aryl group or amino, hydroxyl, 1-piperazine, 1-piperidine, or 1- imidazoline. "Aryl" is defined as an unsaturated carbocyclic or heterocyclic moiety that may be either unsubstituted or substituted with one or more non-interfering substituent (s) . Examples of aryl groups include, without limitation, phenyl, benzyl, naphthyl, indenyl, azulenyl, flucrenyl, anthracenyl, indolyl, isoindolyl, indolinyl, benzofuranyl, benzothiophenyl, indazolyl, benzimidazolyl, benzithiazolyl, tetrahydrofuranyl, tetrahydropyranyl, pyridyl, pyrrolyl, pyrrolidinyl, pyridinyl, pyrimidinyl, purinyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl, quinolizinyl, furyl, thiophenyl, imidazolyl, oxazolyl, benzoxazolyl, thiazolyl, isoxazolyl, isotπazolyl, oxaάiazolyi, triazolyl, thiadiazolyl, pyridazinyl, pyrimidinyl, pyrazolyl, pyrazolinyl, pyrazolidinyl, thienyl, tetra-hydroisoquinolinyl , cinnolinyl, phthalazinyl , quinazolinyl, quinoxalinyl, naphthyridinyi, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl and the like. Possible substituents on an aryl group can be any non- interfering substituent. However, preferred substituents include, without limitation, alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, amino, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, imino, azo, diazo, sulfonyl, sulfoxy, thic, thiocarbonyl, sulfhydryl, halo, haloaikyi, trifluoromethyl, aralkyl and aryl. In the compound of the invention, the multicyclic nuclear ring structure formed with the fused Y ring preferably has an isoquinoline, a quinoline, a naphthalene, a phenanthridine, a phthalazine, a phthalhydrazide, or a quinazoline nucleus. More preferably, the nucleus is one of the following: naphthalene quinoline quinazoline phthalazine isoquinoline isoquinoline Even more preferably, the compound has an isoqumolme, a quinoline, or a naphthalene nucleus. - preferred emoodiment of the invention _s the compound of formula II: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem A and B are independently caroon or nitrogen, with the proviso that at least one of A and B is nitrogen. The ring formed by A and B may be unsubstituted or independently substituted with a non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl or aryl group. Examples of useful fused rings containing A and B in formula II include: Specific examples of particularly preferred compounds of the invention are shown below: III V VI XVI XVII xvi i : and XIX In the compositions and methods of the invention, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R lr R 2 , R 3 , and R 4 are each hydrogen, X is preferably a -COOH group. In other words, for the compositions and methods of the invention, the compound of formula I is preferably Compound XIX above, 8-carboxynaphthalene-I-carboxamide . The compounds of the invention may be useful in a free base form, in the form of pharmaceutically acceptable salts, pharmaceutically acceptable hydrates, pharmaceutically acceptable esters, pharmaceutically acceptable solvates, pharmaceutically acceptable prodrugs, pharmaceutically acceptable metabolites, and in the form of pharmaceutically acceptable stereoisomers. These forms are all within the scope of the invention. In practice, the use of these forms amounts to use of the neutral compound. "Pharmaceutically acceptable salt", "hydrate", "ester" or "solvate" refers to a salt, hydrate, ester, or solvate of the inventive compounds which possesses the desired pharmacological activity and which is neither biologically nor ctnerwise undesirable. Organic acids can be used to produce salts, hydrates, esters, or solvates such as acetate, adicate, alginate, aspartate, benzoate, benzenesulfonate, p- toluenesulfonate, bisulfate, sulfamate, sulfate, naphthylate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentane-propionate, digluconate, dodecylsulfate, ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate, hemisulfate heptanoate, hexanoate, 2-hydroxyethanesulfonate, lactate, maieate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, tosylate and undecanoate. Inorganic aciαs can oe used to produce salts, hydrates, esters, or solvates such as hydrochloride, hydrobromide, hydrciodide, and tr.iocyanate. Examples of suitable base salts, hydrates, esters, or solvates include hydroxides, carbonates, and bicarbonates of ammonia, alkali metal salts such as sodium, lithium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, aluminum salts, and zinc salts. Salts, hydrates, esters, or solvates may also be formed with organic bases. Organic bases suitable for the formation of pharmaceutically acceptable base addition salts, hydrates, esters, or solvates of the compounds of the present invention include those that are non-toxic and strong enough to form such salts, hydrates, esters, or solvates. For purposes of illustration, the class of such organic bases may include mono-, di-, and tnalkylamines, such as methylamme, dimetnylamme, triethylamine and dicyclohexyiamme; mono-, di- or tπhydroxyalkylammes, such as mono-, αi-, and triethanolamme; ammo acids, such as arginine and lysine; guamdme; N-methyl-glucosamine; N-methyl-glucamme; L- glutamme; N-methyl-piperazine; morpholine; ethylenediamme; N-benzyl-phenethylamme; (trihydroxy-methyl) ammoethane; and the like. See, for example, "Pharmaceutical Salts," J. Phar^ . Sci . , 66: 1 , 1-19 (1977). Accordingly, basic nitrogen- containing groups can be quaternized with agents including: lower alkyl halides such as methyl, ethyl, propyl, and butyl chlcmoes, oromides and iodides; dialkyl sulfates such as dimetnyl, diethyl, dibutyl and diamyi sulfates; long chain halides such as αecyl, lauryl, myπstyl and stearyl chlorides, bromides and iodides; and aralkyl halides such as benzyl and phenethyl bromides. The acid addition salts, hydrates, esters, or solvates of the basic compounds may be prepared either by dissolving the free case of a PARP inhibitor in an aqueous or an aqueous alcohol solution or other suitable solvent containing the appropriate acid or base, and isolating the salt by evaporating tne solution. Alternatively, the free case of the PARP inhibitor may be reacted with an acid, as well as reacting the PARP inhibitor having an acid group thereon with a base, such that the reactions are m an organic solvent, in which case the salt separates directly or can be obtained by concentrating the solution. "Pharmaceutically acceptable prodrug" refers to a derivative of tne inventive compounds which undergoes biotransformation prior to exhibiting its pharmacological effect (s) . The prodrug is formulated with the objective (s) of improved chemical stability, improved patient acceptance and compliance, improved bioavailability, prolonged duration of action, improved organ selectivity, improved formulation (e.g., increased hydrosolubiiity) , and/or decreased side effects (e.g., toxicity). The prodrug can be readily prepared from the inventive compounds using methods known m the art, such as those described by Burger ' s Meaicmal Chemistry and Drug Chemistry, Fifth Ed., Vol. 1, pp. 172-178, 949-982 (1995). For example, the inventive compounds can be transformed mto prodrugs by converting one or more of the hydroxy or carboxy groups mto esters. "Pharmaceutically acceptable metabolite" refers to drugs that have undergone a metabolic transformation. After entry into the body, most drugs are substrates for chemical reactions that may change their physical properties and biologic effects. These metabolic conversions, which usually affect the polarity of the compound, alter the way m which drugs are distributed m and excreted from the body. However, in some cases, metabolism of a drug is required for therapeutic effect. For example, anticancer drugs of the antimetabolite class must be converted to their active forms after they have been transported mto a cancer cell. Since must drugs undergo metabolic transformation of some kind, the biochemical reactions that play a role m drug metabolism may be numerous and diverse. The mam site of drug metabolism is the liver, although other tissues may also participate. A feature characteristic of many of these transformations is that the metabolic products are more polar than the parent drugs, although a polar drug αoes sometimes yield a less polar product. Substances with hign lipid/water partition coefficients, which pass easily across memoranes, also diffuse back readily from tubular urine thrcugn the renal tubular cells mto the plasma. Thus, such substances tend to have a low renal clearance and a long persistence in the body. If a drug is metabolized to a more polar compound, one with a lower partition coefficient, its tubular reabsorption will be greatly reduced. Moreover, the specific secretory mechanisms for anions and cations m the proximal renal tubules and m the parenchymal liver cells operate upon highly polar substances. As a specific example, phenacetm (acetophenetidm) and acetanilide are both mild analgesic and antipyretic agents, but are transformed withm the body to a more polar and more effective metabolite, p-hydroxyacetanilid (acetaminophen) , whicn is widely used today. When a dose of acetanilid is given to a person, tne successive metabolites peak ana decay m tne plasma sequentially. During the first hour, aceta-ilid _s tne principal plasma component. In the second hour, as tne acetanilid level falls, the metabolite acetaminophen concentration reaches a peak. Finally, after a few hours, the principal plasma component is a further metaoolite that is inert and can be excreted from the oody. Thus, tne plasma concentrations of one or more metaoomtes, as well as the drug itself, can be pharmacologically important . The reactions involved in drug metabolism are often classified mto two groups, as shown in tiie Table I. Phase I (or functionalization) reactions generally consist of (1) oxiαative ana reductive reactions that alter and create new functional groups and (2) hydrolytic reactions that cleave esters and amiαes to release masked functional groups. These changes are usually m the direction of mcreased polarity. Phase II reactions are conjugation reactions m wnicr the drug, or often a metabolite of the drug, is coupleo to an endogenous suostrate, such as glucuronic acid, acetic acid, or sulfuπc acid. TABLE I Phase I Reactions (functionalization reactions): (1) Oxidation via the hepatic microsomal P450 system: Aliphatic oxidation Aromatic hydroxylation N-Dealkylation O-Dealkylation S-Dealkylation Epoxidation Oxidative deammation Sulfoxide formation Desulfuration N-Oxidation and N-hyoroxylation Dehalogenation (2) Oxidation via non-microsomal mechanisms: Alcohol and aldehyde oxidation Puπne oxidation Oxidative deammation (monoamine oxidase and diamine oxidase) (3) Reduction: Azo and nitro reduction (4) Hydrolysis: Ester and amide hydrolysis Peptide bond hydrolysis Epoxide hydration Phase II Reactions (comuqat on reactions): (1) Glucuronidation ( 2 ) Acetylation (3) Mercaptuπc acid formation (4) Sulfate conjugation (5) N-, 0-, and S-methylation (6) Trans-sulfuration The compounds of the present invention possess one or more asymmetric center (s) and thus can be produced as mixtures (racemic and non-racemic) of stereoisomers, or as individual R- and S-stereoisomers . The individual stereoisomers may be obtained by using an optically active starting material, by resolving a racemic or non-racemic mixture of an intermediate at some appropriate stage of synthesis, or by resolving a compound of formula I. Synthesis of Compounds Many non-carboxamide PARP inhibitors can be synthesized by known methods from starting materials that are known, are themselves commercially available, or may be prepared by methods used to prepare corresponding compounds in the literature. See, for example, Suto et al., "Dihydroisoquinolmones : The Design and Synthesis of a New Series of Potent Inhibitors of Poly (ADP-ribose) Polymerase", An ti cancer Drug Des . , 6 : 101 - 11 '1991), which discloses processes for synthesizing a number of different PARP mnioitors . The compounds of the present invention can also be prepared by using the general synthetic pathway depicted below. A compound of formula I may be prepared by contacting an intermediate of formula III: wherem R l r R 2 , R 3 , R 4 , R 5 and Y are as defined aoove for compounds of formula I of the invention; and "halo" is a chloro, bromo or iodo moiety; with a -COOR 5 radical or a substituted or unsubstituted radical selected from the group consisting of the following carboxylic acid mimics: , and , wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, itself either unsudstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group. The intermediate of formula III can be prepared by methods known in the art. Typically, the reaction shown above ta es place m a solvent inert with respect to the intermediate of formula III. Typical solvents incluαe, for example, tetrahydrofuran ("THF"), methylene chloride, chloroform, lower a anols, dimethylformamide, and a wide variety of other inert organic solvents . The above-described reaction can take place at varying temperatures depending, for example, upon the solvent used, the solubility of the intermediate of formula III m the solvent being used, and the susceptibility of the reactions to oxidize or participate m side reactions. Preferably, however, when the above reaction is used, it takes place at a temperature from about -100°C to about room temperature, preferably from about -80°C to about -0°C. The time required for the above reaction also can vary widely, depending on much the same factors. Typically, however, the reaction ta es withm a time of aoout 5 minutes to aoout 24 nours, preferably from about 10 minutes to an hour . Preferably, the above reaction takes place in the presence of a halo-removal compound that will provide an attractive cation for extraction of the halo anion, such as n-butyllithium. The addition sequence of the intermediate of formula III, the halo-removal compound, a solvent (if used), and the -COOR or acid mimic radical, can vary significantly depending upon the relative reactivities of these materials, the purity of these materials, the temperature at which the reaction xs performed, the degree of agitation used m tne reaction, and tne like. Preferably, nowever, the intermediate of formula III is first dissolved in a solvent, the halo-removal compound is first added, and the -C00R 3 or acid mimic radical is then added. The product, a compound of formula I, is isolated from the reaction mixture by conventional techniques, such as by precipitating out, extraction with an immiscible solvent under appropriate pH conditions, evaporation, filtration, crystallization and the like. Typically, however, the product is removed by acidifying the reaction mixture under aqueous conditions and collecting the precipitated solid material . Other variations and modifications of this invention using the synthetic pathway described above will be obvious to those skilled in the art. In addition, compounds related to 8-carboxy-naphthalene- 1-carboxamide (also known as 8-carbamoyl-naphthalene carboxylic acid), shown below: can oe prepared by known chemical syntheses such as, for exa p.e, that described in Gazz . Chim . Izal . , 79:603-605 (1949 . Moreover, the particular compound shown above is commercially available from Lancaster Synthesis Inc., P.O. Box 1C00, Windham, NH 03087, USA. Typically, the compounds of formula I used in the composition of the invention will have an IC 50 for inhibiting poly (ADP-ribose) polymerase in vitro of 100 μM or lower, preferably 25 μM or lower, more preferably 12 μM or lower and, even more preferably, 12 mM or lower. Pharmaceutical Compositions A further aspect of the present invention is directed to a pharmaceutical composition comprising a pharmaceutically acceptable carrier or a diluent and a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures (hereafter, "a compound of formula I") . The formula I compounds of the invention are useful in the manufacture of pharmaceutical formulations comprising an effective amount thereof in conjunction with or as an admixture with excipients or carriers suitable for either enteral or parenteral application. As such, formulations of the present invention suitable for oral administration may be in the form of discrete units such as capsules, cachets, tablets, troche or lozenges, each containing a predetermined amount of the active ingredient; m the form of a powder or granules; in the form of a solution or a suspension m an aqueous liquid or nonaqueous liquid; or in the form of an oil-m-water emulsion or a water-in-oil emulsion. The active ingredient may also be m the form of a bolus, electuary, or paste . The composition will usually be formulated into a unit dosage form, such as a tablet, capsule, aqueous suspension or solution. Such formulations typically include a solid, semisolid, or liquid carrier. Exemplary carriers include lactose, dextrose, sucrose, sorbitol, mannitol, starcnes, gum acacia, calcium phosphate, mineral oil, cocoa outter, oil of thecoroma, alginates, tragacanth, gelatin, syrup, methyl cellulose, polyoxyethylene sorbitan monolaurate, methyl hydroxybenzoate, propyl hydroxybenzoate, talc, magnesium stearate, and the like. Particularly preferred formulations include tablets and gelatin capsules comprising the active ingredient together with (a) diluents, such as lactose, dextrose, sucrose, mannitol, sorbitol, cellulose, dried corn starch, and glycine; and/or (b) lubricants, such as silica, tamum, stearic acid, its magnesium or calcium salt, and polyethylene glycol . Tablets may also contain binders, such as magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose and polyvinylpyrrolidone; carriers, such as lactose and corn starcn; dismtegrants, such as starches, agar, alginic acid or its sodium salt, and effervescent mixtures; and/or absorbents, colorants, flavors, and sweeteners. The compositions of the invention may be sterilized and/or contain adjuvants, such as preserving, stabilizing, swelling or emulsifying agents, solution promoters, salts for regulating osmotm pressure, and/or buffers. In addition, the composition may also contain other therapeutically valuaoie substances. Aqueous suspensions may contain emulsifying and suspending agents combined with the active ingredient. All oral dosage forms may further contain sweetening and/or flavoring and/or coloring agents. τh ese compositions are prepared according to conventional mixing, granulating, or coating methods, respectxvely, and contain about 0.1 to 75% of the active ingredient, preferably about 1 to 50% of the same. A tablet may be made by compressing or molding the active ingredient optionally with one or more accessory ingredients. Compressed tablets may Pe prepared oy compressing, m a sumac_e machine, the active ingredient m free-clowmg form such as a powder or granules, optionally mixed with a binder, lubricant, inert diluent, surface active, or dispersing agent. Molded tablets may be made oy molding, m a suitable machine, a mixture of the powdered active ingredient and a suitable carrier moistened with an inert liquid diluent. When administered parenterally, the composition will normally be in a unit dosage, sterile injectable form (aqueous isotonic solution, suspension or emulsion with a pharmaceutically acceptable carrier. Sucr carriers are preferably non-toxic, parenterally-acceptable and contain non-t h erapeutic diluents or solvents. Examples or sucn carriers include water; aqueous solutions, such as salme (isotonic sodium chloride solution), Ringer's solution, dextrose solution, and Hanks' solution; and nonaqueous carriers, such as 1, 3-butanedιol, fixed oils (e.g., corn, cottonseed, peanut, sesame oil, and synthetic mono- or di- glyceride) , ethyl oleate, and isopropyi myπstate. Oleaginous suspensions can be formulated according to techniques known in the art using suitable dispersing or wetting agents and suspending agents. Among the acceptable solvents or suspending mediums are sterile fixed oils. For this purpose, any bland fixed oil may be used. Fatty acids, such as oleic acid and its glyceπde derivatives, including olive oil and castor oil, especially m their polyoxyethylated forms, are also useful in the preparation of mjectables. These oil solutions or suspensions may also contain long-chain alcohol diluents or dispersants. Sterile salme is a preferred carrier, and the compounds are often sufficiently water soluble to be made up as a solution for all foreseeable needs. The carrier may contain minor amounts of additives, such as substances that enhance solub_mty, _sotonιcιty, and chemical stability, e.g., anti- oxiαarts, buffers and preservatives. When administered rectally, the composition will usually be formulated into a unit dosage form such as a suppository or cacnet. These compositions can be prepared by mixing the compound with suitable non-imtatmg excipients that are solid at room temperature, but liquid at rectal temperature, such that they will melt m the rectum to release the compound. Common excipients include cocoa butter, beeswax and polyethylene glycols or other fatty emulsions or suspensions . Moreover, the compounds may be administered topically, especially wnen the conditions addressed for treatment mvome areas or organs readily accessiole by topical application, including neurological disorders of the eye, the skm or the _ower intestinal tract. For topical application to the eye, or ophthalmic use, the compounds can be formulated as micronized suspensions m isotonic, pH-adjusted sterile salme or, preferably, as a solution in isotonic, pH-adjusted sterile salme, either with or without a preservative such as benzylalkonium chloride. Alternatively, the compounds may be formulated mto ointments, such as petrolatum. For topical application to the skm, the compounds can be formulated mto suitable ointments containing the compounds suspended or dissolved in, for example, mixtures with one or more of tne following: mineral oil, liquid petrolatum, white petrolatum, propylene glycol, polyoxyethylene compound, polyoxypropylene compound, emulsifying wax and water. Alternatively, the compounds can be formulated mto suitable lotions or creams containing the active compound suspended or dissolved in, for example, a mixture of one or more of the following: mineral oil, sorbitan monostearate, polysorbate 60, cetyl ester wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and water. Topical application to the lower intestinal tract can be effected in rectal suppository formulations (see above) or in suitaoie enema formulations. Formulations suitable for nasal or ouccal administration, (such as self-propelling powαer dispensing formulations), may comprise about 0.1% to about 5% w/w of the active ingredient or, for example, about 1% w/w of the same. In addition, some formulations can be compounded mto a sublmgual troche or lozenge. The formulations may conveniently be presented in unit dosage form and may be prepared by any of the methods well known in the art of pnarmacy. All methods include the step of ormgmg tne active ingredient mto association with the carrier which constitutes one or more accessory ingredients. In general, the formulations are prepared oy uniform-_ * and intimately bringing the active ingredient into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product mto the desired formulation. In a preferred embodiment, the carrier is a biodegradable polymer or mixture of biodegradable polymers witn appropriate time release characteristics and release kinetics suitable for providing efficacious concentrations of the compounds of the invention over a prolonged period of time without the need for frequent re-dosmg. The composition of the present invention can be incorporated into the biodegradable polymer or polymer mixture m any suitable manner Known to one of ordinary skill in the art and may form a homogeneous matrix with the biodegradable polymer, or may be encapsulated in some way withm the polymer, or may be molded mto a solid implant. In one embodiment, the biodegradable polymer or polymer mixture is used to form a soft "depot" containing the pharmaceutical composition of the present invention that can be administered as a fiowable liquid, for example, by injection, but which remains suff_cιently viscous to maintain the pharmaceutical composition withm the localized area around the injection site. The degradation time of the depot so formed can be vaπeo from several days to a few years, depending upon the polymer selected ano its molecular wight. By using a polymer composition m miectao e form, even the need to maKe an incision may be eliminated. In any event, a flexiole or flowaole delivery "depot" will adjust to the shape of the space it occupies with the body with a minimum of trauma to surrounding tissues. The pharmaceutical composition of the present invention is used n amounts that are therapeutically effective, and may depend upon the desired release profile, the concentration of the pharmaceutical composition required for tne sensitizing effect, and the length of time that the pharmaceutical composition has to be released for treatment. I"ie composition of the invention is preteraDlv admm_stereo as a capsule or tablet containing a single or divided dose of the compound, or as a sterile solution, suspension, or emulsion, for parenteral administration m a single or divided dose. In another preferred embodiment, the compounds of the invention can be prepared in lyophilized form. In this case, 1 to 100 mg of a PARP inhibitor may be lyophilized in individual vials, together with a carrier and a buffer, such as mannitol and sodium phosphate. The composition may then be reconstituted in the vials with bacteπostatic water before administration. In tne compositions and metnoos of the invention, a preferred empodiment is when, m the compound of formula I, Y is a fused, 6-membered, aromatic carbocyclic ring, R l f R 2 , R 3 , and R 4 are each hydrogen, and X is a -COOH group. A compound αefined by the foregoing sentence is 8- carooxynapntnalene-1-carboxamιde, wnich has the following structure : The compounds of the invention are used m the composition amounts that are therapeutically effective. Whim the effective amount of the PARP inhibitor will αepenα upon the particular compound being used, amounts of the these compcmds varying from about 1% to about 65% have been easily incorporated into liquid or solid carrier delivery systems. Compositions and Methods for Effecting Neuronal Activity Preferably, according to the invention, an effective therapeutic amount of the compounds and compositions described above are administered to animals to effect a neuronal activity, preferably one that is not mediated b NMDA "eurotoxicity . Such neuronal activity may consist of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration and treatment of a neurological disorder. Accordingly, the present invention further relates to a method of effecting a neuronal activity in an animal, comprising administering an effective amount of the compound of formula I to said animal. Further, the compounds of the invention inhibit PARP activity and, thus, are believed to be useful for treating neural tissue damage, particularly damage resulting from cerebral ischemia and reperfusion injury or neurodegenerative diseases m mamma-S . Examples of neurological disorders that are treatable by the method of using the present invention include, without limitation, trigeminal neuralgia; glossopharyngeal neuralgia; Bell's Palsy; myasthenia gravis; muscular dystrophy; amyotrophic lateral sclerosis; progressive muscular atrophy; progressive bulbar inherited muscular atrophy; herniated, ruptured or prolapsed invertebrate disk syndromes; cervical spondylosis; plexus disorders; thoracic outlet destruction syndromes; peripheral neuropathies such as those caused by lead, dapsone, ticks, porphyπa, or Guillam-Barre syndrome; Alzheimer's disease; Huntington's Disease and Parkinson's disease . Tne method of the present invention is particularly useful for treating a neurological disorder selected from the group consisting of: peripheral neuropathy caused by physical injury or disease state; head trauma, such as traumatic brain injury; physical damage to the spmal cord; stroke associated with bram damage, such as vascular stroke associated with hypoxia and bram damage, focal cerebral ischemia, global cerebral ischemia, and cerebral reperfusion injury; demyelmat g diseases, such as multiple sclerosis; and neurological disorders related to neurodegeneration, such as Alzheimer's Disease, Parkinson's Disease, Huntington's Disease and amyotrophic lateral sclerosis (ALS). Treating Other PARP-Related Disorders The compounds, compositions and methods of the present invention are particularly useful for treating or preventing tissue damage resulting from cell death or damage due to necrosis or apoptosis. The compounds, compositions and methods of the invention can also be used to treat a cardiovascular disorder in an animal, by administering an effective amount of the compound of formula to the animal. As used herein, the term "cardiovascular disorders" refers to those disorders that can either cause ischemia or are caused by reperfusion of the heart. Examples include, but are not limited to, coronary artery disease, angma pectoris, myocardial infarction, cardiovascular tissue damage caused by cardiac arrest, cardiovascular tissue damage caused by cardiac oyoass, cardiogemc shock, and related conditions that would be known oy those of ordinary skill in the art or which involve dysfunction of or tissue damage to the heart or vasc._ature, especially, but not limited to, tissue damage related to PARP activation. For example, the methods of the invention are oelieved to be useful for treating cardiac tissue damage, particularly damage resulting from cardiac ischemia or caused by reperrusion injury in animals. The methods of the invention are particularly useful for treating cardiovascular disorders selected f o"' the group consisting of: coronar artery disease, such as atherosclerosis; angma pectoris; myocardial infarction; myocardial ischemia and cardiac arrest; cardiac bypass; and cardiogemc shock. The methods of the invention are particularly helpful m treating the acute forms of the above cardiovascular disorders. Further, the methods of the invention can be used to treat tissue damage resulting from cell damage or death due to necrosis or apoptosis, neural tissue damage resulting from ischemia and reperfusion injury, neurological disorders and neurodegenerative diseases; to prevent or treat vascular stroκe; to treat or prevent cardiovascular disorders; to treat other conditions and/or disorders such as age-reiated macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cachexia, cancer, degenerative diseases of skeletal muscle involving replicative senescence, diabetes, head trauma, immune senescence, inflammatory bowel disorders (such as col_tιs and Crohn ' s disease), muscular dystrophy, osteoarthritis, osteoporosis, chronic and/or acute pam (such as neuropathic pam), renal failure, retinal ischemia, septic shock (such as endotoxic shock) , and skm aging; to extend the lifespan and proliferative capacity of cells; to alter gene expression of senescent cells; or to radiosensitize tumor cells Further still, the methods of the invention can oe used to treat cancer and to radiosensitize tumor cells. The term "cancer" is interpreted broadly. The compounds of the present invention can be "anti-cancer agents", which term also encompasses "anti-tumor cell growth agents" and "anti- neop-astic agents". For example, tne methods of the invention are useful for treating cancers and racmsensitizmg tumor cells in cancers such as ACTH- producing tumors, acute lymphocytic leukemia, acute non_ymphocytιc leukemia, cancer of the adrenal cortex, bladder cancer, bram cancer, breast cancer, cervical cancer, cnronic lymphocytic leukemia, chronic myelocytic leukemia, ccmrectal cancer, cutaneous T-celx lympnoma, endometπal cancer, esophageal cancer, Ewmg's sarcoma, gallbladder cancer, hairy cell leukemia, head & neck cancer, Hodgkm's lympnoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/or non-small cell), malignant peritoneal effusion, malignant pleural effusion, melanoma, mesothelioma, multiple myeloma, neuroblastoma, non-Hodgkm ' s lymphoma, osteosarcoma, ovarian cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penile cancer, retmoblastoma, skm cancer, soft-tissue sarcoma, sαuamous cei_ carcinomas, stomach cancer, test cular cancer, tnyroic cancer, tropnoblastic neoplasms, uterine cancer, vaginal cancer, cancer of the vulva and Wilm's tumor. The term "radiosensitizer", as used herein, is defined as a molecule, preferably a low molecular weight molecule, administered to animals m therapeutically effective amounts to increase the sensitivity of the cells to be radiosensitized to electromagnetic radiation and/or to promote the treatment of diseases which are treatable with electromagnetic radiation. Diseases which are treatable with electromagnetic radiation include neoplastic diseases, benign and malignant tumors, and cancerous cells. Electromagnetic radiation treatment of other diseases not listed herein are also contemplated by the present invention. The terms "electromagnetic radiation" and "radiation" as used herein includes, but is not limited to, radiation having the wavelength of 10^ c to 10 meters. Preferred embodiments of the present invention employ the electromagnetic radiation of: gamma-radiation (10 " - c to 10 " 3 m) x-ray radiation (10-- 1 to 10 " ) , ultraviolet light (10 nm to 400 nm) , visible light (400 nm to 700 nm) , infrared radiation (700 nm to 1.0 mm), and microwave radiation (1 mm to 30 cm) . Radiosensitizers are known to increase the sensitivity of cancerous cells to the toxic effects of electromagnetic radiation. Several mechanisms for the mode of action of radiosensitizers have oeen suggested in the literature mc^mmg: hypoxic ceil radiosensitizers ( e.g., 2- nitroimidazole compounds, and oenzotriazme dioxide compounds) promote the reoxygenation of hypoxic tissue and/or catalyze the generation of damaging oxygen radicals; non- hypoxic cell radiosensitizers (e.g., nalogenated pyrimidmes) can be analogs of DNA bases and preferentially incorporate into the DNA of cancer cells and thereby promote the radiation-mduced breaking of DNA molecules and/or prevent the normal DNA repair mechanisms; and various other potential mechanisms of action have been hypothesized for radiosensitizers m the treatment of disease. Many cancer treatment protocols currently employ radiosensitizers activated by the electromagnetic radiation of x-rays. Examples of x-ray activated radiosensitizers include, but are not limited to, the following: metronidazole, misonidazole, αesmethylmisoniαazole, pimonidazole, etanidazole, nimorazole, mitomycm C, RSU 1069, SR 4233, E09, RB 6145, nicotmamide, 5-bromodeoxyuπdme (BUdR) , 5-ιododeoxyurιdme (IUdR), bromodeoxycytidme, fluorodeoxyuπdme (FudR), hydroxyurea, cisplatm, and therapeutically effective analogs and derivatives of the same. Pnotoαynamic therapy ( PDT ) of cancers employs visible light as the radiation activator of the sensitizing agent. Examples of photodynamic radiosensitizers include the following, but are not limited to: hematoporphyrm deri v atives, Photofrm, benzoporphyrm derivatives, NPe6, tin etioporphyrm SnET2, pheoborbide-a, bacteπochlorophyll-a, naphthalocyanmes, phthalocyanmes, zmc phthalocyanme, and therapeutically effective analogs and derivatives of the same . Radiosensitizers may be administered in conjunction with a therapeutically effective amount of one or more other compounds, including but not limited to: compounds which promote the incorporation of radiosensitizers to the target cel_s; compounds wnich control the flow of therapeutics, ^utr_e ts, and/or oxygen to the target cells; chemctnerapeutic agents which act on the tumor with or without additional radiation; or other therapeutically effective compounds for treating cancer or other disease. Examples of additional therapeutic agents that may be used in conjunction with radiosensitizers include, but are not limited to: 5-fluorouracil, leucovorin, 5 ' -arnmo- 5 ' deoxythymidme, oxygen, carbogen, red cell transfusions, perfluorocarbons (e.g., Fluosol-DA) , 2,3-DPG, BW12C, calcium channel blockers, pentoxyfyllme, antiangiogenesis compounds, hyαra_azιne, and L-BSO. Examples of chemotherapeutic agents that may be used m conjunction with radiosensitizers mcl_αe, but are not limited to: adriamycin, camptctnecin, carooplatin, cisplatm, daunorubicm, docetaxel, doxorubicin, mterferon (alpha, beta, gamma), interleukin 2, lrmotecan, pacl_taxel, topotecan, and therapeutically effective analogs and derivatives of the same. The compounds of the present invention may also θe used for radiosensitizmg tumor cells. The term "treating" refers to: v ι) preventing a disease, disorder or condition from occurring in an animal that may be predisposed to the disease, disorder and/or condition, but has not yet oeen diagnosed as having it; (ii) inhibiting the disease, disorder or condition, i.e., arresting its development; and m) relieving the disease, disorder or condition, i.e., causing regression of the disease, disorder and/or condition. Administration For medical use, the amount required of a compound of formula I to achieve a therapeutic effect will vary according to the particular compound administered, the route of aαmm.stration, the mammal under treatment, and the particular disorder or disease concerned. A suitable syste m ic dose of a compound of formula I for a mammal suffering from, or likely to suffer from, any condition as described herein is typically in the range of about 0.1 to about 100 mg of base per kilogram of oody weight, preferably from about 1 to about 10 mg/kg of mammal body weight. It is understood that the ordinarily skilled physician or veterinarian will readily be able to determine and prescribe the amount of the compound effective for the desired prophylactic or therapeutic treatment. In so proceeding, the physician or veterinarian may emplc ^ an intravenous bolus followed by an mtravenous infusion and repeated administrations, as considered appropriate. In the methods of the present invention, the compounds may be administered, for example, orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, subl mgual ly , vagmally, mtraventricularly, or via an implanted reservoir m dosage formulations containing conventional non-toxic pharmaceutically-acceptable carriers, adjuvants and vehicles. Parenteral includes, but is not limited to, the following examples of administration: intravenous, subcutaneous, intramuscular, mtraspmal, mtraosseous, intraperitoneal, intrathecal, mtraventπcular, mtrasternal or mtracranial injection and infusion techniques, sucn as by subdural pump. Invasive techniques are preferred, particularly direct administration to damaged neuronal tissue. Whne it is possible for the compound of formula I to be administered alone, it is preferable to provide it as a part of a pharmaceutical formulation. To be effective therapeutically as central nervous system targets, the compounds used in the methods of the present invention should readily penetrate the blooα-bram barrier when peripherally administered. Compounds which cannot penetrate the blood-brain barrier, however, can still be effectively administered by an mtraventricular route. The compounds used m the methods of the present invention may oe administered by a single αose, mumiple discrete doses or continuous infusion. Since the compounds are small, easily diffusible and relatively stable, they are well suited to continuous infusion. Pump means, particularly subcutaneous or subdural pump means, are preferred for continuous infusion. For the methods of the present invention, any effective administration regimen regulating the timing and sequence of doses may be used. Doses of the compounds preferably include pharmaceutical dosage units comprising an efficacious quantity of active compound. By an efficacious quantity is meant a quantity sufficient to inhibit PARP activity and/or derive the desired beneficial effects therefrom through administration of one or more of the pharmaceutical dosage units. In a particularly preferred embodiment, the dose is sufficient to prevent or reduce the effects of vascular stroke or other neurodegenerative diseases. An exemplary daily dosage unit for a vertebrate host comprises an amount of from about 0.001 mg/kg to about 50 mg/kg. Typically, dosage levels on the order of about 0.1 mg to about 10,000 mg of the active ingredient compounα are useful m the treatment of the above conditions, with preferred levels bemg about 0.1 mg to about 1,000 mg . The specific αose level for any particular patient will vary depending updn a variety of factors, including the activity of the specific compound employed; the age, body weight, general health, sex, and diet of the patient; the time of administration; the rate of excretion; any combination of the compound with other drugs; the severity of the particular disease being treated; and the form and route of administration. Typically, in vitro dosage-effect results provide useful guidance on the proper doses for patient administration. Studies m animal models can also be helpful. The considerations for determining the proper dose leve_s are well-known in the art. In methods of treating nervous insult (particularly acute mchemic stroke and global ischemia caused by drowning or nead trauma) , the compounds of the invention can be co- administered with one or more other therapeutic agents, preferably agents which can reduce the risk of stroke (such as aspirin) and, more preferably, agents which can reduce the risk of a second ischemic event (such as ticlopidme) . The compounds and compositions can be co-admmistered with one or more therapeutic agents either 'ι) together in a single formulation, or (n) separately m individual formulations designed for optimal release rates of tneir respective active agent. Each formulation may contain rrom about 0.01% to about 99.99% by weight, preferably from about 3.5% to about 60% by weight, of the compound of the invention, as well as one or more pharmaceutical excipients, such as wetting, emulsifying and pH buffering agents. When the compounds used in the methods of the invention are administered in combination with one or more other therapeutic agents, specific dose levels for those agents will depend upon considerations such as those identified above for compositions and methods of the invention m general . For example, Table II below provides known median dosages for selected chemotherapeutic agents that may be administered m combination with tne compounds of the invention to such diseases or various cancers. TABLE II For the methods of the present invention, any administration regimen regulating the timing and sequence of delivery of the compound can be used and repeated as necessary to effect treatment. Such regimen may include pretreatment and/or co-administration with additional therapeutic agents. To maximize protection of nervous tissue from nervous insult, the compounds of the invention should be administered to the affected cells as soon as possible. In situations where nervous insult is anticipated, the compounds are advantageously administered before the expected nervous msuit. Such situations of increased likelihood of nervous insult include surgery, such as carotid endarterectomy, cardiac, vascular, aortic, orthopedic surgery; endovascular procedures, such as arterial catheterization (carotid, vertebral, aortic, cardia, renal, spmal, Adamkiewicz) ; injections of embolic agents; the use of coils or balloons for -emostasis; interruptions of vasculaπty for treatment of bram lesions; and predisposing medical conditions such as crescendo transient ischemic attacks, emboli and sequential strokes. Where pre-treatment for stroke or ischemia is impossible or it is important to bring the compounds of the invention mto contact with the affected cells as soon as possmle, either during or after the event. In the time period between strokes, however, diagnosis and treatment procedures should be minimized to save the cells from further damage and death. Therefore, a particularly advantageous mode of administration with a patient diagnosed with acute multiple vascular strokes is by implantation of a subdural pump to deliver the compound (s) of the invention directly to the infarct area of the bram. Even if comatose, it is expected that the patient would recover more quickly that he or sne would without this treatment. Moreover, in any conscious state of the patient, it xs expected tha^ any residual neurological symptoms, as well as the re-occurrence of stroke, would be reduced. As to patients diagnosed with other acute disorders believed to be related to PARP activity, such as diabetes, arthritis and Crohn ' s disease, the compound of the invention should also be administered as soon as possible m a single or divided dose. Depending on the patient's presenting symptoms and the degree of response to the initial administration of the compound of the invention, the patient may further receive additional doses of the same or different compounds of the invention, by one of the following routes: parenterally, such as oy injection or oy intravenous administration; orally, such as by capsule or tablet; by implantation of a biocompatible, biodegradable polymeric matrix delivery system comprising the compound; or by direct administration to the infarct area by insertion of a subdural pump or a central line. It is expected that the treatment would alleviate the disorder, either m part or in its entirety and that fewer further occurrences of tne disorder would develop. It also is expected that the patient would suffer fewer residual symptoms. Where a patient is diagnosed with an acute disorder prior to the availability of the compounds of the invention, the patient's condition may deteriorate due to the acute diso der and become a chronic αisorder by the time that the compounds are available. Even when a patient receives a compound of formula I for the chronic disorder, it is also expected tnat the patient's condition would stabilize and actually improve as a result of receiving the compound. The compounds of the present invention may also be used to prevent disorders by prophylactic administration of the compounds of the present invention. EXAMPLES The following examples are illustrative of preferred emboαiments of inventions and are not to be construed as limiting the present invention thereto. All polymer molecular weights are mean average molecular weights. All percentages are based on the percent by weight of the final delivery system or formulation prepared unless otherwise indicated, and all totals equal 100% by weight. Example 1: Preparation of 5-Carbamoylqumolme-4- Carboxylic Acid A mixture of m-cyanoaniline (1.0 g, 8.46 mmol) and diethylethoxylene malonate (1.97 g, 9.13 mmol) was stirred at 100-110°C for one hour to form a homogenous solution. The solution was cooled to room temperature, and pale yellowish crystals were formed. The crystals were collected and washed with exane, giving 2.33 g (yield 100%) of ethyl-α- carbethoxy-β- (m-cyanoanilino) acrylate (1), mp 109-111 :: C. The acrylate ester (1) was added through the top of an air condenser in portions to boiling diphenyl ether (10 ml) . After a few minutes of addition, crystals formed. The resulting mixture was heated at the same temperature for 30 minutes and then the cooled to room temperature. The crystals were collected and washed with hexane, to give 1.79 g of the regioisomer esters (2) (yield 89.5%), mp 305-307°C (dec . ) . The esters (2) (1.79 g, 7.39 mmol) were suspended m 10% NaOh 15 ml), and the mixture was heated to reflux for one hour and cooled. Decolorizing charcoal (1.0 g > was added, and the mixture was heated to reflux for an additional 10 minutes. The solid was removed, and the filtrate was acidified to pH 5 with 10% HCl. A cream precipitate was collected, washed with water and hexane, and dried to give the acid isomer mixtures (3), 1.63 g ^ yield 100%), mp>320°C. The acids (3) (0.5 g, 2.33 mmol) were added to pre- heateα polyphosphoric acid (PPA) (2.2 g) m portions over a period of about 8 minutes with stirring at 255-265 c C. The mixture was heated at the same temperature for 20 minutes, cooleα to room temperature, and then poured mto ice-water. An undesireα precipitate, 0.259 g of 7-ammocarconyl-4- hydroxyisoαumolme, was formed, co ^ .ecteα ana wasrea with water (yield 59.1%) . The remaining aqueous solution was adjusted to pH 5-6 with NaHC0 3 solution to precipitate out 138 mg of 4-hydroxyqumolme-5-carboxamιde (4) (yield 31.5%), mp>250X. Compound (4) (1.0 g, 5.88 mmol) was suspended in P0C1 3 , and tne resulting mixture was heated to a temperature of 130°C (bath temperature) . After 10 minutes, the suspension became a dar solution, and gases were vigorously releaseα. After one hour and forty-five minutes, the reaction was complete, as srown oy thm layer chromatography. The reaction ~ xture was cooled to room temperature, poured mto ice water and basified with 10% NaOH to pH 9. A pale purple precipitate was formed, collected and washed with water. The solid was dissolved in MeOH and decolorized with activated carbon. The solid was removed and the remaining filtrate was evaporated under a vacuum to afford 300 mg (yield 25%) of a white crystalline powder, 4-hydroxyqumolme-5-carboxamιde 5), mp 205-207°C. n-Butyllithium (3.88 mmol) m hexane was added siowly to a solution of 4-hydroxyqumoIme-5-carθoxamιde (5) (400 mg, 1.94 mmol) in THF (10 ml) at a temperature of -78°C. Next, dry C0 2 gas was bubbled mto the mixture for 15 minutes at - "8 C. Saturateα NH 4 C1 solution (20 ml) was also addeα. The mixture was warmed to room temperature, concentrateα, and the remaining residue was dissolved m a saturateα Na 2 C0 3 solution. The resulting aqueous solution was washed with ether and then acidified to pH 6 with IN HCl to afford 124 mg of tne product compound (6) as a solid. Example 2 Approximate IC cn Data for Selected Compounds The IC 50 of with respect to PARP inhibition was determined for several compounds by a PARP assay using purified recombinant human PARP from Trevigen (Gaithersburg, MD) , as folxows: The PARP enzyme assay was set up on ice m a olume of 100 microiiters consisting of 10 mM Tπs-HCl (ph 8.0 , _ mM MgCI 2 , 28 mM KCl, 28 mM NaCl, 0.1 mg/ml of -erring sperm DNA (activated as a 1 mg/ml stock for 10 minutes m a 0.15% hydrogen peroxide solution), 3.0 micromolar [3H] nicotmamide adenme dmucleotide (470 mci/mmoie) , 7 micrograms/ml PARP enzyme, and various concentrations of the compounds to be tested. The reaction was initiated by incubating the mixture at 25°C. After 15 minutes' mcuoation, the reaction was terminated by adding 500 microiiters of ice cold 20% (w/v) trichloroacetic acid. The precipitate formed was transferred onto a glass fiber filter (Packard Unifilter- GF/3 and washed three times with ethanol. After the filter was cried, the radioactivity was determined by scintillation counting . Using the PARP assay described above, approximate IC 50 values were obtained for the following compounds: Similar IC 50 values are obtained for the carboxamide compounds of the invention. Example 3 Neuroprotective Effect of DPQ on Foca Cerebral Ischemia in Rats Focal cerebral ischemia was produced by cauterization of the right distal MCA (middle cerebral artery) with bilateral temporary common carotid artery occlusion in maie Long-Evans rats for 90 minutes. All procedures performed on the animals were approved by the University Institutional Animal Care and Use Committee of the University of Pennsylvania. A total of 42 rats (weights: 230-340 g) obtained from Charles River were used in this study. The animals fasted overnight with free access to water prior to the surgical procedure. Two hours prior to MCA occlusion, varying amounts (control, n=14; 5 mg/kg, n=7; 10 mg/kg, n=7; 20 mg/kg, n=7; and 40 mg/kg, n=7) of the non-carboxamide compound, 3,4- dihyαro-5- [4- ( 1-piperιdinyl ) -butoxy] -1 (2H) -isoqumolinone ("DPQ") were dissolved in dimethyl sulfoxide (DMSO) using a somcator. A volume of 1.28 ml/kg of the resulting solution was injected mtraperitoneally mto fourteen rats. The rats were then anesthetized with halothane (4% for induction and 0.8%-1.2% for the surgical procedure; in a mixture of 70% nitrous oxide and 30% oxygen. The body temperature was monitored by a rectal probe and maintained at 37.5 + 0.5°C with a heating blanket regulated by a homeothermic blanket control unit (Harvard Apparatus Limited, Kent, U.K.). A catheter (PE-50) was placed into the tail artery, and arterial pressure was continuously monitored and recorded on a Grass polygraph recorder (Model 7D, Grass Instruments, Qumcy, Massachusetts). Samples for blood gas analysis (arterial pH, Pa0 2 and PaC0 2 ) were also taken from the tail artery catheter and measured with a blooα gas analyzer (ABL 30, Radiometer, Copenhagen, Denmark) . Arterial blood samples were obtained 30 minutes after MCA occlusion. The head of the animal was positioned in a stereotaxic frame, and a right parietal incision between the right lateral canthus and the external auditory meatus was made. Using a dental drill constantly cooled with saline, a 3 mm burr hole was prepared over the cortex supplied by the right MCA, 4 mm lateral to the sagittal suture and 5 mm caudal to the coronal suture. The dura mater and a thm inner bone layer were kept, care being taken to position the prode over a tissue area devoid of large blood vessels. The flow probe (tip diameter of 1 mm, fiber separation of 0.25 mm) was lowered to tne bottom of tne cranial burr nole using a micromanipulator . The probe was held stationary by a probe holder secured to the skull with dental cement. The microvascular blood flow m the right parietal cortex was continuously monitored with a laser Doppler flowmeter (FloLab, Moor, Devon, U.K., and Peπflux 4001, Peπmed, Stoc nolm, Sweden) . Focal cerebral ischemia was produced by cauterization of the αistal portion of the right MCA with bilateral temporary common carotid artery (CCA) occlusion by the procedure of Chen et al., "A Model of Focal Ischemic Stroke in the Rat: Reproducible Extensive Cortical Infarction", Stroke 17: ^38-43 (1986 and/or Liu et al . , "Polyethylene Glycol-conjugated Superoxide Dismutase and Catalase Reduce Ischemic Bram Injury", Am . J. Physiol . 256:H589-93 (1989), both of which are hereby incorporated by reference. Specifically, bilateral CCA's were isolated, and loops made from polyethylene (PE-10) catheter were carefully passed around the CCA's for later remote occlusion. The incision made previously for placement of the laser doppler probe was extended to allow observation of the rostral end of the zygomatic arch at the fusion point using a dental drill, and the dura mater overlying the MCA was cut. The MCA distal to its crossing with the inferior cerebral vem was lifted by a fine stainless steel hook attached to a micromanipulator and, following bilateral CCA occlusion, the MCA was cauterized with an electrocoagulator . The burr hole was covered with a small piece of Gelform, and the wound was sutured to maintain the bram temperature withm the normal or near-normal range. After 90 minutes of occlusion, the carotid loops were released, the tail arterial catheter was removed, and all of the wounds were sutured. Gentamicm sulfate (10 mg/ml) was topically applied to the wounds to prevent infection. The anesthetic was discontinued, and the animal was returned to his cage after awakening. Water and food were allowed ad libitum. Two hours after MCA occlusion, the animals were given the same doses of the PARP inhibitor as in the pre-treatment . Twenty-four nours after MCA occlusion, the rats were sacrificed with an intraperitoneal injection of pentobarbital sodium (150 mg/kg) . The bram was carefully removed from the skull and cooled in ice-cold artificial CSF for five minutes. The cooled bram was then sectioned the coronal plane at 2 mm intervals using a rodent bram matrix (RBM-4000C, ASI Instruments, Warren, Michigan) . The bram slices were incubated m phosphate-buffered salme containing 2% 2,3,5- tπphenyltetrazolium chloride (TTC) at 37°C for ten minutes. Color photographs were taken of the posterior surface of the stained slices and were used to determine the damaged area at eac cross-sectional level using a computer-based image analyzer (NIH Image 1.59) . To avoid artifacts due to edema, the damaged area was calculated by subtracting the area of the normal tissue in the hemisphere ipsilateral to the stroke from the area of the hemisphere contralateral to the stroke, by the method of Swanson et al . , "A Semiautomated Method for Measuring Bra Infarct Volume", J. Cereb . Blood Flow Metabol . 10:290-93 (1990), the disclosure of which is hereby incorporated oy reference. The total volume of infarction was calculated by summation of the damaged volume of the bram slices . The cauterization of the distal portion of the right MCA with oilaterax temporary CCA occlusion consistently produced a well-recognized cortical infarct in the right MCA territory of each test animal. There was an apparent uniformity m the distribution of the damaged area as measured by TTC staining in each group, as shown m Figure 1. In Figure 1, the distribution of the cross-sectional infarct area at representative levels along the rostrocaudal axis was measured from the mteraural line in non-treated animals and m animals treated with 10 mg/kg of 3,4-dιhydro- 5- [4- ( 1-pιperιdmyl) -butoxy] -1 (2H) -isoqumolmone . The area of damage was expressed as mean ± standard deviation. Significant differences between the 10 mg-treated group and the control group were indicated ( * p<0.02, ** p<0.01, ** p<0.001). The 5 mg/kg and 20 mg/kg curves fell approximately halfway between the control and the 10 mg/kg curves, whereas the 40 mg/kg curve was close to the control. The 5, 20 and 40 mg/kg curves were omitted for clarity. PARP inhibition led to a significant decrease in the damaged volume m the 5 mg/kg-treated group (106.7 + 23.2 mm 3 , p<0.001), the 10 mg/kg-treated group (76.4 + 16.8 mm 3 , p<0.001), and the 20 mg/kg-treated group (110.2 + 42.0 mm\ p<0.01), compared to the control group (165.2 + 34.0 mm J . The data are expressed as mean + standard deviation. The significance of differences between groups was determined using an analysis of variance (ANOVA) followed by Student's t-test for individual comparisons. There was no significant difference between the control and the 40 mg/kg-treated group (135.6 + 44.8 mm 3 ). However, there were significant differences between the 5 mg/kg- treated group and the 10 mg/kg-treated group (p<0.02), and between the 10 mg/kg-treated group and the 40 mg/kg-treated group (p<0.01), as shown m Figure 2. In Figure 2, the effect of intraperitoneal administration of 3, 4-dιhydro-5- [4- (1-pιperιdmyl ) -butoxy] - 1 (2H) -isoqumolmone on the infarct volume was depicted graphically. The volumes of infarct were expressed as mean + standard deviation. Significant differences between the treated groups and the control group were indicated ( " p<0.01, ** p<0.001) . It is not clear why a high dose (40 mg/kg) of the PARP inhibitor, 3, 4-dιhydro-5- [4- ( 1-pιperιdmyl) -butoxy] - 1 (2H) -isoqumolmone, was less neuroprotective. The U-shaped dose-response curve may suggest dual effects of the compound. However, overall, the in vivo administration of the inhibitor led to a substantial reduction in infarct volume in the focal cerebral ischemia model m the rat. This result indicated that the activation of PARP plays an important role in the pathogenesis of bram damage in cerebral ischemia. The values of arterial blood gases (Pa0 2 , PaC0 2 and pH) were withm the physiological range in the control and treated groups with no significant differences in these parameters among the five groups, as shown below m Table 2. A "steady state" MABP was taken following completion of the surgical preparation, just prior to occlusion; an "ischemia" MABP .vas taken as the average MABP during occlusion. See Table III below: TABLE III = Significantly different from the steady state value, p<0.05. - Significantly different from the steady state value, p<0.01. There were no significant differences m any physiological parameter, including mean arterial blood pressure (MABP) , prior to MCA and CCA occlusion among the five groups. Although MABP was significantly elevated following occlusion in all five groups, there were no significant differences in MABP during the occlusion period among the groups. Since the blood flow values obtained from the laser doppler were in arbitrary units, only percent changes from the baseline (prior to occlusion) were reported. Right MCA and bilateral CCA occlusion produced a significant decrease in relative blood flow m the right parietal cortex to 20.8 + 7.7 % of the baseline m the control group (n=5) , 18.7 + 7.4 % m the 5 mg/kg-treated group (n=7), 21.4 + 7.7 % m the 10 mg/kg-treated group (n=7) and 19.3 + 11.2 % m the 40 mg/kg-treated group (n=7) . There were no significant differences in the blood flow response to occlusion among the four groups. In addition, blood flow showed no significant changes throughout the entire occlusion period in any group. Following release of the carotid occlusions, a good recovery of blood flow (sometimes hyperemia) was observed the right MCA territory of all animals. Reperfusion of the ischemic tissue resulted in the formation of NO and peroxynitrite, in addition to oxygen-derived free radicals. All of these radicals have been shown to cause DNA strand breaks and to activate PARP. This example provided evidence that the related compounds of the present invention are effective m inhibiting PARP activity. Example 4 : Assay for Neuroprotective Effects on Focal Cerebral Ischemia in Rats Focal cerebral ischemia experiments are performed using male Wistar rats weighing 250 - 300 g, which are anesthetized with 4% halothane. Anesthesia is maintained with 1.0-1.5% halothane until the end of surgery. The animals are installed in a warm environment to avoid a decrease m body temperature during surgery. An anterior midline cervical incision is made. The right common carotid artery (CCA) is exposed and isolated from the vagus nerve. A silk suture is placed and tied around the CCA n proximity to the heart. The external carotid artery (ECA) is then exposed and ligated with a silk suture. A puncture is made in the CCA and a small catheter (PE 10, Ulπch & Co., St-Gallen, Switzerland) is gently advanced to the lumen of the internal carotid artery (ICA). The pterygopalat e artery is not occluded. The catheter is tied m place with a silk suture. Then, a 4-0 nylon suture (Braun Medical, Cπssief, Switzerland) is introduced mto the catheter lumen and is pushed until the tip blocks the anterior cerebral artery. The length of catheter mto the ICA is approximately 19 mm from the origin of the ECA. The suture is maintained m this position by occlusion of the catheter with heat. One cm of catheter and nylon suture are left protruding so that the suture can be withdrawn to allow reperfusion. The skm incision is then closed with wound clips. The animals are maintained in a warm environment during recovery from anesthesia. Two hours later, the animals are re-anesthetized, the clips are discarded, and the wound is re-opened. The catheter is cut, and the suture is pulled out. The catheter is then obturated again by heat, and wound clips are placed on the wound. The animals are allowed to survive for 24 hours with free access to food and water. The rats are then sacrificed with C0 2 and decapitated. The brains are immediately removed, frozen on dry ice and stored at -80°C. The brains are then cut m 0.02 mm-thick sections in a cryocut at -19°C, selecting one of every 20 sections for further examination. The selected sections are stained with cresyl violet according to the Nissl procedure. Each stained section is examined under a light microscope, and the regional infarct area is determined according to the presence of cells with morphological changes. Various doses of the compounds of the invention are tested in this model. The compounds are administered in either a single dose or a series of multiple doses, i.p. or i.v., at different times, both before or after the onset of ischemia. Compounds of the invention are found to provide protection from ischemia m the range of about 20 to 80%. Example 5: Effects on Heart Ischemia/Reperfusion Iniury in Rats Female Sprague-Dawley rats, each weighing about 300-350 g are anesthetized with mtrapentoneal ketamme at a dose of 150 mg/kg. The rats are endotracheally mtubated and ventilated with oxygen-enriched room air using a Harvard rodent ventilator. Polyethylene catheters inserted mto the carotid artery and the femoral vem are used for artery blood pressure monitoring and fluid administration respectively. Arterial pC0 2 is maintained between 35 and 45mm Hg by adjusting the respirator rate. The rat chests are opened by median sternotomy, the pericardium is incised, and the hearts are cradled with a latex membrane tent. Hemodynamic data are obtained at baseline after at least a 15-minute stabilization period following the end of the surgical operation. The LAD (left anterior descending) coronary artery is ligated for 40 minutes, and then re-perfused for 120 minutes. After 120 minutes' reperfusion, the LAD artery is re-occluded, and a 0.1 ml bolus of monastral blue dye is injected mto the left atrium to determine the ischemic risk region. The hearts are then arrested with potassium chloride and cut mto five 2-3 mm thick transverse slices. Each slice is weighed and incubated in a 1% solution of trimethyltetrazolium chloride to visualize the mfarcted myocardium located with the risk region. Infarct size is calculated by summing the values for each left ventricular slice and is further expressed as a fraction of the risk region of the left ventricle. Various doses of the compounds of the invention are tested m this model. The compounds are given either in a single dose or a series of multiple doses, i.p. or i.v., at different times, both before or after the onset of ischemia. The compounds of the invention are found to have ischemia/reperfusion injury protection in the range of 10 to 40 percent. Therefore, they protect against ischemia-mduced degeneration of rat hippocampal neurons in vitro. Example 6: Retinal Ischemia Protection A patient just diagnosed with acute retinal ischemia is immediately administered parenterally, either by intermittent or continuous intravenous administration, a compound of formula I, either as a single dose or a series of divided doses of the compound. After this initial treatment, and depending on the patient's presenting neurological symptoms, the patient optionally may receive the same or a different compounα of the invention m the form of another parenteral dose. It is expected by the inventors that significant prevention of neural tissue damage would ensue and that the patient's neurological symptoms would considerably lessen due to the administration of the compound, leaving fewer residual neurological effects post-stroke. In addition, it is expected that the re-occurrence of retinal ischemia would be prevented or reduced. Examp.e 7 : Treatment of Retinal Ischemia A patient has just been diagnosed with acute retinal ischemia. Immediately, a physician or a nurse parenterally administers a compound of formula I, either as a single dose or as a series of divided doses. The patient also receives the same or a different PARP inhibitor by intermittent or continuous administration via implantation of a biocompatible, biodegradable polymeric matrix delivery system comprising a compound of formula I, or via a subdural pump inserted to administer the compound directly to the mfarct area of the bram. It is expected by the inventors mat the patient would awaken from the coma more quickly thar if the compound of the invention were not administered. The treatment is also expected to reduce the severity of the patient's residual neurological symptoms. In addition, it is expected that re-occurrence of retinal ischemia would be reduced. Example 8 : Vascular Stroke Protection A patient ust diagnosed with acute vascular stroke is immediately administered parenterally, either by intermittent or continuous intravenous administration, a compound of formula I, either as a single dose or a series of divided doses of the compound. After this initial treatment, and depending on the patient's presenting neurological symptoms, the patient optionally may receive the same or a different compound of the invention m the form of another parenteral dose. It is expected by the inventors that significant prevention of neural tissue damage would ensue and that the patient ' s neurological symptoms would considerably lessen due to the administration of the compound, leaving fewer residual neurological effects post-stroke. In addition, it is expected that the re-occurrence of vascular stroke would be prevented or reduced. ExamPxe 9: Treatment of Vascular Stroke A patient has just been diagnosed with acute multiple vascular strokes and is comatose. Immediately, a physician or a nurse parenterally administers a compound of formula I, either as a single dose or as a series of divided doses. Due to the comatose state of the patient, the patient also receives the same or a different PARP inhibitor by intermittent or continuous administration via implantation of a Piocompatxble, biodegradable polymeric matrix delivery system comprising a compound of formula I, or via a subdural pump inserted to administer the compound directly to the mfarct area of the bram. It is expected by the inventors that the patient would awaken from the coma more quickly than if tne compound of the invention were not administered. The treatment is also expected to reduce the severity of the patient's residual neurological symptoms. In addition, it is expected that re-occurrence of vascular stroke would be reduced. Example 10: Preventing Cardiac Reperfusion Iniury A patient is diagnosed with life-threatening cardiomyopathy and requires a heart transplant. Until a donor heart is found, the patient is maintained on Extra Corporeal Oxygenation Monitoring (ECMO) . A donor heart is then located, and the patient undergoes a surgical transplant procedure, during which the patient is placed on a heart-lung pump. The patient receives a compound of the invention mtracardiac withm a specified period of time prior to re-routing his or her circulation from the heart-lung pump to his or her new heart, thus preventing cardiac reperfusion injury as the new heart begins to beat independently of the external heart-lung pump. Example 11: Septic Shock Assay Groups of 10 C57/BL male mice weighing 18 to 20 g were administered a test compound, 1-carboxynaphthaiene-l- carocxamide at the doses of 60, 20, 6 and 2 mg/kg, daily, by intraperitoneal (IP) injection for three consecutive days. Each animal was first challenged with lipopolysaccharide (LPS, from E. Coli, LD 100 of 20 mg/animal IV) plus galactosamme (20 mg/animal IV) . The first dose of test compound in a suitable vehicle was given 30 minutes after challenge, and the second and third doses were given 24 hours later on day 2 and day 3 respectively, with only the surviving animals receiving the second or third dose of the test compound. Mortality was recorded every 12 hours after challenge for tne three-day testing period. 1-Carooxy- naphthaiene-1-carboxamιde provided a protection against mortality from septic shock of about 40%. Based on these results, other compounds of the invention are expected to provide a protection against mortality exceeding about 35%. Example 12 : In vi tro Radiosensitization The human prostate cancer cell line, PC-3s, were plated in 6 well dishes and grown at monolayer cultures in RPMI1640 supplemented with 10% FCS. The cells are maintained at 37°C in 5% C0 2 and 95% air. The cells were exposed to a dose response (0.1 mM to 0.1 μM) of 3 different PARP inhibitors of Formula I disclosed herein prior to irradiation at one sublethal dose level. For all treatment groups, the six well plates were exposed at room temperature in a Seifert 250kV/15mA irradiator with a 0.5 mm Cu/1 mm. Cell viability was examined by exclusion of 0.4% trypan blue. Dye exclusion was assessed visually by microscopy and viable cell number was calculated by subtracting the number of cells from the viable cell number and dividing by the total number of cells. Cell proliferation rates were calculated by the amount of 3 H- thy dme incorporation post-irradiation . The PARP inhibitors show radiosensitization of the cells. Example 13 In vivo Radiosensitization Before undergoing radiation therapy to treat cancer, a patient is administered an effective amount of a compound or a pharmaceutical composition of the present mvention. The compound or pharmaceutical composition acts as a radiosensitizer and making the tumor more susceptible to radiation therapy. Example 14 Measuring Altered Gene Expression in mRNA Senescent Cells Human fibroblast BJ cells, at Population Coupling (PDL) 94, are plated in regular growth medium and then changed to low serum medium to reflect physiological conditions descrioed in Lmskens, et al . , Nucleic Acids Res . 23:16:3244- 3251 (1995). A medium of DMEM/199 wupplemented with 0.5% bovine calf serum is used. The cells are treated daily for 13 days with the PARP inhibitor of Formula I as disclosed herein. The control cells are treated with and without the solvent used to administer the PARP inhibitor. The untreated old and young control cells are tested for comparison. RNA is prepared from the treated and control cells according to the techniques described m PCT Publication No. 96/13610 and Northern blotting is conducted. Probes specific for senescence-related genes are analyzed, ano treated and control cells compared. In analyzing the results, the lowest leve_ of gene expression m arbitrarily set at 1 to provide a basis for comparison. Three genes particularly relevant to age-related cnanges in the skm are collagen, collagenase and elastin. West, Arcn . Derm . 130:87-95 (1994). Elastm expression of the cells treated with the PARP inhibitor of Formula I is significantly increased in comparison with the control cells. Elastm expression is significantly higher in young cells compared to senescent cells, and thus treatment with the PARP inhibitor of Formula I causes elastin expression levels in senescent cells to change to levels sιm_mr to those found m much younger cells. Similarly, a beneficial effect is seen in collagenase and collagen expression with treatment with the PARP inhibitors of Formula I. Example 15 Measuring Altered Gene Expression Protein in Senescent Cells Approximately 105 BJ cells, at PDL 95-100 are plated and grown in 15 cm dishes. The growth medium is DMEM/199 supplemented with 10% bovice calf serum. The cells are treated daily for 24 hours with the PARP inhibitors of Formula I (100 μg/ 1 mL of medium) . The cells are washed with phosphate buffered solution (PBS), then permeablized wi " 4% paraformaldehyde for 5 minutes, then washed wit" PBS, and treated with 100% cold metnanoi for 10 minutes. The methanol is removed and the cells are washed with PBS, and then treated with 10% serum to block nonspecific antibody binding. About 1 mL of the appropriate commercially available antibody solutions (1:500 dilution. Vector) is added to the cells and the mixture incubated for 1 hour. The cells are rinsed and washed three times with PBS. A secondary antibody, goat anti-mouse IgG (1 mL) with a biotm tag is added along with 1 mL of a solution containing streptavidm conjugated to alkaline phosphatase and 1 mL of NBT reagent (Vector) . The cells are washed and changes in gene expression are noted colorimetrically . Four senescence- specific genes — collagen I, collagen III, collagenase, and interferon gamma -- in senescent cells treated with the PARP inhibitor of Formula I are monitored and the results show a decrease m interferon gamma expression witn no observable change in the expression levels of the other three gens, demonstrating that the PARP inhibitors of Formula I can alter senescence-specific gene expression. Example 16 Extending or Increasing Proliferative Capacity and Lifespan of Cells To demonstrate the effectiveness of the present method for extending the proliferative capacity and lifespan of cells, human fibroblast cells lines (either W138 at Population Doubling (PDL) 23 or BJ cells at PDL π l ) are thaweα and plated on T75 flasks and allowed to grow m normal medium (DMEM/M199 plus 10% bovme calf serum) for about a week, at which time the cells are confluent, and the cultures are therefor ready to be subdivided. At the time of subdivision, the media is aspirated, and the cells rinsed with phosphate buffer saline (PBS) and then trypsinized. The cells are counted with a Coulter counter and plated at a density of 10 cells per cm 2 in 6-well tissue culture plates in DMEM/199 medium supplemented with 10% bovme calf serum and varying amounts (O.lOμM, and ImM: from a 100X stock solution m DMEM/M199 medium) of a PARP inhibitor of Formula I as αisclosed herein. This process is repeated every 7 days until the cell appear to stop dividing. The untreated (control) cells reach senescence and stop dividing after about 40 days in culture. Treatment of cells with 10 μM 3-AB appears to have little or no effect in contrast to treatment with 100 μM 3-AB which appears lengthen the lifespan of the cells and treatment with 1 mM 3-AB which dramatically increases the lifespan and proliferative capacity of the cells. The cells treated with 1 mM 3-AB will still divide after 60 days m culture. Example 16: Neuroprotective Effects of Formula I on Chronic Constriction Iniury (CCI) in Rats Adult male Sprague-Dawley rats, 300-350 g, are anesthetized with intraperitoneal 50 mg/kg sodium pentooarbital . Nerve ligation is performed by exposing one side of the rat's sciatic nerves and dissecting a 5-7 mm-long nerve segment and closing with four loose ligatures at a 1.0-1.5-mm, followed by implanting of an intrathecal catneter and inserting of a gentamicm sulfate-flushed polyethylene (PE-10) tube mto the subarachnoid space through an incision at the cisterna magna. The caudal end of the catheter is gently threaded to the lumbar enlargement and the rostral end is secured with dental cement to a screw embedded in the skull and the skm wound is closed with wound clips. Therma^ hyperalgesia to radiant neat m assesseα by using a paw-withdrawal test. The rat is placed m a plastic cylinder on a 3-mm thick glass plate with a radiant heat source from a projection bulb placed directly under the plantar surface of the rat's hindpaw. The paw-withdrawal latency is defined as the time elapsed from the onset of radiant heat stimulation to withdrawal of the rat's hindpaw. Mechanical hyperalgesia is assessed by placing the rat in a cage with a bottom made of perforated metal sheet with many small square holes. Duration of paw-withdrawal is recorαed after pricking the mid-plantar surface of the rat's hindpaw with the tip of a safety pm inserted through the cage bottom. Mechano-allodynia is assessed by placing a rat in a cage similar to the previous test, and applying von Frey filaments in ascending order of bending force ranging from 0.07 to 76 g to the mid-plantar surface of the rat's hindpaw. A von Frey filament is applied perpendicular to the skm and depressed slowly until it bends. A threshold force of response is defined as the first filament in the series to evoke at least one clear paw-withdrawal out of five applications. Dark neurons are observed bilaterally withm the spmal corα αorsal norn, particularly m laminae I-II, of rats 8 days after unilateral sciatic nerve ligation as compared with sham operated rats. Various doses of differing compounαs of Form ^ _a I are tested m this model and show that the Formula I compounds reduce both incidence of dark neurons and neuropathic pam behavior m CCI rats. Tne invention being thus described, it will be obvious that the same may be varied m many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications are mteroed to be included withm the scope of the following claxms .

Claims: We C - i im : A compound of formula I or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or 0, S, N-containing heterocyclic ring, wnerem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -C00R 5 or a substituted or unsubstituted moiety selected from the group consisting of and , wherem R is hyαrogen, alkyi, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R x is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 f R 3 ' ^ 4 an R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, amino, hydroxyl, 1-pιperazme, 1-pιperιdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, pnencxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl; provided that, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 2. The compound of claim 1, wherem Y has at east one site of unsaturation . 3. The compound of claim 1, wherem said compound has formula II : II or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem A and B are independently carbon or nitrogen and are optionally and independently unsubstituted or substituted with alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl or aryl group; provided that at least one cf A and B is nitrogen. -■ . The compound of claim 1, wherem Y represents the atoms necessary to form a 5- to 6-membered carbocyclic ring . 5. The compound of claim 4, wherem Y is aromatic. 6. The compound of claim 4, wherem Y represents the atoms necessary to form a fused benzene ring. ~ . The compound of claim 4, wherem Y is non-aromatic. 8. The compound of claim 1, wherem Y represents the atoms necessary to form a 5- to 6-membered, N-contammg ring . 9. Tne compounα of claim 8, wherem Y is aromatic. 10. The compound of claim 8, where Y is non- aromatic . 11. The compound of claim 1, wherein said compound has an isoqumolme, a qumolme, a naphthalene, a phenanthridme, a phthalazme, a phthalhydrazide, or a qumazolme nucleus. 12. The compound of claim 11, wherem said compound has an isoqumolme, a qumolme or a naphthalene nucleus. 13. The compound or claim 1, wherein the compound is selected from the group consisting of II III 17 - XVI XVII , and XVIII 14. The compound of claim 1, wherem said compound has an IC 50 of 100 uM or lower for inhibiting poly(ADP- ribose) polymerase m vitro. 15. The compound of claim 1, wherem said compounα has a>~ IC 50 of 25 μM or lower for inhibiting poly (ADP- noose polymerase m vitro. 16. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wnerem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non- mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR s or a substituted or unsubstituted moiety selected from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, αyαroxyl, 1-pιperazme, 1-pιperιdιre, or 1-ιmιdazolme, and are eitner unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, tnio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl; provided that, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 1". The composition of claim 16, wherem Y has at least one site of unsaturation. 18. The pharmaceutical composition of claim 16, wherem said compound has formula II: II or a Pharmaceutically acceptable salt, hydrate, ester, solvate, proorug, metabolite, stereoisomer, or mixtures thereof; wherem: ^ and B are independently carbon or nitrogen ano are optionally and independently unsubstituted or substituted with alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl or aryl group; provided that at least one of A and B is nitrogen. 19. The composition of claim 16, wherem Y represents the atoms necessary to form a fused benzene ring. 22 . The composition of claim 16, wherem said compound has an isoqumolme, a qumolme, a naphthamne, a phenanthridme, a phthalazme, a phthalhydrazide, or a qumazolme nucleus. 21. The composition of claim 20, wherem said compound has an isoqumolme, a qumolme or a naphthalene nucleus . 22. The composition of claim 16, wherein Y represents the atoms necessary to form a 5- to 6- membered carbocyclic riπσ . 23. The composition of claim 22, where Y is aromatic . 24. The composition of claim 22, wherem Y is non- aromatic . 25. The composition of claim 16, wherem Y represents the atoms necessary to form a 5- to 6- membered, N- containmg heterocyclic ring. 26. The composition of claim 25, wherem Y is arcmatic . 27 . The composition of claim 25 , wherem Y is non- aromatic . 28 . The composition of claim 16 , wherem the compound is selected from the group consisting of I I I I I IV V VI VII VIII IX X XI XII XIII XIV XV XVI XVII XVIII and XIX 29. The composition of claim 16, wherein said compound has an IC 50 of 100 μM or lower for inhibiting poly (ADP-ribbse) polymerase m vitro. 30. The composition of claim 16, wherem said agent has - IC 50 cf 25 μM or lower for inhibiting poly(ADP- ribosej polymerase m vitro. 31. The composition of claim 16, wherem said composition is administered as a sterile solution, suspension or emulsion, in a single or divided dose. 32. The composition of claim 16, wherem said composition is administered as a solid implant capab_e of releasing the compound over a prolonged period of t me. 33. The composition of claim _6, wherem saiα composition is administered as a capsule or tablet containing a single or divided dose of said compounα. 34. The composition of claim 16, wherem the carrier comprises a biodegradable polymer. 35. The composition of claim 34, wherem the composition is a solid implant. 36. The composition of claim 34, wherem the biodegradable polymer releases the compound of formula I over a prolonged period of time. 37. The pharmaceutical composition of claim 16 for treatment or prevention of diseases or conditions selected from the group consisting of tissue αamage resulting from cell damage or death due to necrosis or apoptosis, neuronal mediated tissue damage or diseases, neural tissue damage resulting from ischemia and reperfusion injury, neurological disorders and neurodegenerative diseases, vascular stroke, cardiovascular disorders, age-relateα macuiar degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cachexia, cancer, dege n eratιve diseases of skeletal muscle involving replicative senescence, diabetes, head trauma, immune senescence, inflammatory bowel disorders, muscular dystrophy, osteoarthritis, osteoporosis, chronic pair, acute pam, neuropathic pam, nervous insult, peripheral nerve injury, renal failure, retinal ischemia, septic shock, and skm aging, diseases or disorders relating to lifespan or proliferative capacity of cells, and diseases or disease conditions induced or exacerbated by cellular senescence . 38. A pharmaceutical composition comprising a pharmaceutically acceptable carrier ana a compound of formu_a I: I or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present m an amount effective for inhibiting PARP activity; and wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom ( s) therein are unsubstituted or independently substituted with at least one non- mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring i and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycioalky_ or cyc_o- alkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alky ^ , alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, nydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 39. The composition of claim 38 wherem, when Y is a fusee, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. -0 The composition of claim 38, wherem the compound ^1. A pharmaceutical composition comprising a pharma- ceutmally acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present m an amount that is effective for effecting a neuronal activity not mediated by NMDA toxicity; and wherem: represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s ) therein are unsubstituted or independently substituted with at least one non- mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -C00R 5 or a substituted or unsubstituted moiety selected from the group consisting of and where R is hydrdgen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri m hydrogen, alkyl, alkenyl, cycloalkyx or cyc_o- alkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdιne, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, nydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonv _, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 42. The composition of claim 41 wherem, when Y is a fuseo, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 , a ~ d R 4 are each hydrogen, X is not a -COOH group. 43 The composition of claim 41, wherem the compound 44. The composition of claim 41, wherem the neuronal ac ivity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration, and treatment of a neurological disorder. -5. The comoosition of claim 44, wherem said damaged neurc-s result from cerebral ischemia or reperfusion mjurv . 46. The composition of claim 44, wherem the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, traumatic bram injury, physical damage to the sp al cord, stroke associated with bram damage, demyelmatmg disease and neurological disorder relating to neurodegeneration. 47. The composition of claim 46, wherem the neurological disorder relating to neurodegeneration _s selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, Huntington's Disease and amyotrophic lateral sclerosis. 48. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present in an amount that is effective for treating arthritis; and wherein: 1 represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one nor- mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or haio substituent; X is at the I-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selecteα from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R x is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdme, or 1-ιmιdazolιne, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, αiazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalky ^ , trifluoromethyl, aralkyl and aryl. 49. The composition of claim 48, wherem the compound ;0. A pharmaceutical composition comprising a pharma- ceucmaily accebtab.e carrier and a compounα of formula I or a pnarmaceutically acceptable salt, hydrate, ester, solv,ite, proαrug, metabolite, stereoisomer, or mixtures ther*;θf, wherein the compound of formula I is present m an amou' it that is effective for treating diabetes; and vvher - represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s ) therein are unsubstituted or independently substituted with at least one non- mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or alkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloamyi or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloa_ yl or cycloalkenyl group; R 2 , R 3 , R 4 and R s are independently hyαrogen, alkw, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1-pιperιdιne, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, lsocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 51. The composition of claim 50 wherem, when Y is a fused, 6-membered, aromatic carbocyclic ring, and Ri, R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 52. A pharmaceutical composition comprising a o"arma- ceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wnerem the compound of formula I is present in an amount tnat is effective for treating an inflammatory bowe_ disorder; and wherem: 2 represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consistinα of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R x is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazιne, 1- pioeπdme, or 1-ιmιdazolιne, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 53. The composition of claim 52 wherein, when Y is a fuseα, 6-memoered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 54. The composition of claim 52, wherem the compound is 55. The composition of claim 52, wherem the oowel disorαer is colitis. 56. The composition of claim 52, wherein tne bowel disorder is Crohn ' s disease. 5 7 . A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present m an amount that is effective for treating a cardiovascular disorder; and wherem: represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of , and , wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cyclo- amenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; i is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently nydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidine, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloamyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 58. The composition of claim 57, wherem, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 ana R 4 are each hydrogen, X is not a -COOH group. 59. The composition of claim 57, wherem the compound is 60. The composition of claim 57, wherem the cardio- vascular disorder is coronary artery disease, myocarαial infarction, angma pectoris, cardiogemc shock and cardio ¬ vascular tissue damage. cl. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound o formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wnerem the compound of formula I is present in an amount that is effective for treating septic shock; ana wherein: 2 represents the atoms necessary to form a fuseα 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituteα with at least one non-mterfermg alkyl, alkenyi, cycloalkenyl, aralkyl, aryl, carboxy or haio substituent; 2 is at the 1-posιtιon of ring i and is -COOR 5 or a substituted or unsubstituteα moiety selectee frcm the group consisting of , and , wherein R' is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmidazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, amino, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 62. The composition of claim 61, wherein, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 ano R 4 are each hydrogen, X is not a -COOH group. 63. The composition of claim 61, wherem the compound is 64. The composition of claim 61, wherein the type of septic shoc is endotoxic shock. 65. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present m an amount that is effective for treating cancer; ana wherem: 1 represents the atoms necessary to form a fuseα 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-containmg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-position of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherein R is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloa_kyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidine, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 66. The composition of claim 65, wherem when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 67. The composition of claim 65, wherem the compound is 68. The composition of claim 65, wherem the cancer is selected from the group consisting of ACTH-producmg tumors, acute lymphocytic leukemia, acute nonlymphocytic leukemia, cancer of the adrenal cortex, bladder cancer, bram cancer, breast cancer, cervix cancer, chronic lympnocytic leukemia, chronic myelocytic leukemia, comrectal cancer, cutaneous T-cell lympnoma, endometπal cancer, esopnageai cancer, Swing's sarcoma, gallblaαder cancer, hairy cell leukemia, head & neck cancer, Hodgkm's lymphoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/or non-small cell), malignant peritoneal effusion, malignant pleural effusion, melanoma, mesotnelioma, multiple myeloma, neuroblastoma, non- Hodgkm's lymphoma, osteosarcoma, ovary cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penis cancer, retinoblastoma, skm cancer, soft-tissue sarcoma, squamous cell carcinomas, stomacn cancer, cancer, thyroid cancer, trophoblastic neoplasms, cancer of tne uterus, vaginal cancer, cancer of the vulva ana Wilm's tumor. 69. The composition of claim 65, wherem the carrier comprises a biodegradable polymer. 70. The composition of claim 69, wherem the composition is a solid implant. "1. The composition of claim 69, wherem the biodegradable polymer releases the compound of formula I - Ill - over a prolonged perioα of time . 72. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound oi formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, proαrug, metabolite, stereoisomer, or mixtures thereof, wherem the compound of formula I is present m an amount that is effective for radiosensitizmg tumor cells; and wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, caroocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyx, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carooxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR s or a substituted or unsubstituted moiety selecteα from the group consisting of and wnerem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyx, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , P 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, αiazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 73. The composition of claim 72, wherein when Y is a fused, 6-membered, aromatic carbocyclic ring, and R 1; R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 74. The composition of claim 72, wherem the compound is 75. The composition of claim 72, wherein said tumor cells are selected from the group consisting of ACTH- producing tumors, acute lymphocytic leukemia, acute nonlymphocytic leukemia, cancer of the adrenal cortex, bladder cancer, bram cancer, breast cancer, cervix cancer, chronic lymphocytic leukemia, chronic myelocytic leukemia, colorectal cancer, cutaneous T-cell lymphoma, endometπal cancer, esophageal cancer, Ewmg's sarcoma, gallbladder cancer, hairy cell leukemia, head & neck cancer, Hodgkm's lymphoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/or non-small cell), malignant peritoneal effusion, malignant pleural effusion, melanoma, mesothelioma, multiple myeloma, neuroblastoma, non-Hodgkm ' s lymphoma, osteosarcoma, ovary cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penis cancer, retinoblastoma, skm cancer, soft-tissue sarcoma, squamous cell carcinomas, stomach cancer, testicular cancer, thyroid cancer, tropnoblastic neoplasms, cancer of the uterus, vagina- cancer, cancer of the vulva and Wilm's tumor. 76. The composition of claim 72, wherem the carrier comprises a biodegradable polymer. " 7. The composition of claim 76, where the composition is a solid implant. 78. The composition of claim 76, wherem the biodegradable polymer releases the compound of formula I over a prolonged period of time. 79. A method of inhibiting PARP activity comprising administering a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: i represents the atoms necessary to form a fuseo 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and where R is hydrogen, alkyl, alkenyl, cycloalkyl or cyclo- alkenyl, ana is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; i is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 80 The method of claim 79, wherem Y has at least one site of unsaturation. 31. The method of claim 79, wherem saiα compound has formula II: II or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem A and B are independently carbon or nitrogen and are optionally and independently unsubstituted or substituted with alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl or aryl group; provided that at least one of A and B is nitrogen. 82. The method of claim 81 wherein, when Y is a fuseα, 6-membered, aromatic carbocyclic ring, and R x , R 2 , R 3 ana R 4 are each hydrogen, X is not a -COOH group. 83. The method of claim 81, wherein the compound is 84. The method of claim 79, wherem Y represents the atoms necessary to form a fused benzene ring. 85. The method of claim 79, wherein said compound has an isoquinoline, a quinoline, a naphthalene, a phenanthridme, a phthalazme, a phthalhydrazide, or a qumazolme nucleus. 86. The method of claim 79, wherem said compound has an isoquinoline, a quinoline or a naphthalene nucleus. 87. The method of claim 79, wherem Y represents the atoms necessary to form a 5- to 6-membered carbocyclic ring. 88. The method of claim 87, wherein Y is aromatic. 89. The method of claim 87, wherein Y is non- aromatic . 90. The method of claim 79, wherem Y represents the atoms necessary to form a 5- to 6-membered, N-contammg heterocyclic ring. 91. The method of claim 90, wherem Y is aromatic. 92. The method of claim 90, wherem Y is non- aromatic . 93. The method of claim 79, wherem the compound is selected from the group consisting of II III VII VIII IX X XI XII XVI XVII XVIII and XIX 94. The method of claim 79, where when Y is a fused, 6-membered, aromatic carbocyclic ring, and R lr R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 95. The method of claim 79, wherem the compounα is 96. The method of claim 79, wherem said compound has an IC 50 of 100 μM or lower for inhibiting poly (ADP- ribose) polymerase in vitro. 97. The method of claim 79, where said compound has an IC 50 of 25 μM or lower for inhibiting poly(ADP- πbose) polymerase m vitro. 98. The method of claim 79, wherem said pharmaceutical composition is in a carrier comprising a bioαegradable polymer. 99. The method of claim 98, wherem the biodegradable polymer carrier is in the form of a solid implant . 100. The method of claim 98, wherem the biodegradable polymer releases the compound of formula I over a prolonged period of time. 101. The method of claim 79 further comprising treating or preventing diseases or conditions selected from the group consisting of tissue damage resulting from cell damage or death due to necrosis or apoptosis, neuronal mediated tissue damage or diseases, neural tissue damage resulting from ischemia and reperfusion injury, neurological disorders and neurodegenerative diseases, vascular stroke, cardiovascular disorders, age-related macular degeneration, AIDS and other immune senescence diseases, arthritis, atherosclerosis, cachexia, cancer, degenerative diseases of skeletal muscle involving replicative senescence, diabetes, head trauma, immune senescence, inflammatory bowel disorders, muscular dystrophy, osteoarthritis, osteoporosis, chronic pam, acute pam, neuropathic pam, nervous msult, peripheral nerve injury, renal failure, retinal ischemia, septic shock, and skm aging, diseases or disorders relating to lifespan or proliferative capacity of cells, and diseases or disease conditions induced or exacerbated by cellular senescence . 102. A method of effecting a neuronal activity not mediated by NMDA toxicity in an animal comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of , and , wherem R is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 103. The method of claim 102, wherem when Y is a fused, 6-memoered, aromatic carbocyclic ring, and R x , R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 104. The method of claim 102, wherem the compound is 105. The method of claim 102, wherem the neuronal activity is selected from the group consisting of stimulation of damaged neurons, promotion of neuronal regeneration, prevention of neurodegeneration, and treatment of a neurological disorder. 106. The method of claim 105, wherem said damaged neurons result from cerebral ischemia or reperfusion injury. 107. The method of claim 105, wherem the neurological disorder is selected from the group consisting of peripheral neuropathy caused by physical injury or disease state, traumatic bram injury, physical damage to the spmal cord, stroke associated with bram damage, demyelmatmg disease and neurological disorder relating to neurodegeneration. 108. The method of claim 107, wherem the neurological disorder relating to neurodegeneration is selected from the group consisting of Alzheimer's Disease, Parkinson's Disease, Huntington's Disease and amyotrophic lateral sclerosis. 109. A method of treating arthritis m an animal comprising administering to said animal an effective amount of a compound of formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: . represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carcocycnc or N-contammg heterocyclic ring, wnerem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consistmg of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalk\l or cycloalkenyl group; x is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperid e, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, nalo, haloalkyl, trifluoromethyl, aralkyl and aryl. 110. The method of claim 109, wherem when Y is a fused, 6-membered, aromatic carbocyclic ring, and R x , R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 111. The method of claim 109, wherem the compound is 112. A method of treating diabetes in an ammax comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: i represents the atoms necessary to form a fuseα 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg neterocyclic ring, wherem Y and any heteroatom ( s) therein are unsubstituted or independently substituted vvith at ^ east one non-mterfermg alkyl, alkeny_, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR s or a substituted or unsubstituted moiety selecteα from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; i is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmιdazolme, and are eitner unsubstituted or substituted with a moiety selected from tne group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amiαo, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyx, sulfoxy, thio, thiocarbonyl, sulfhydryl, naio, haloalkyl, trifluoromethyl, aralkyl and aryl. 113. The method of claim 112, wherem when Y is a fused, 6-membered, aromatic, carbocyclic ring, and R l r R 2 , R 3 , and R 4 are each hydrogen, X is not a -COOH group. 114. The method of claim 112, wherem the compound is 115. A method of treating an inflammatory bowel disorder in an animal comprising administering to said anima- an effective amount of a comoound of formula I: I or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: i represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s ) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at tne 1-posιtιon of ring i and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl - 121 or cycloalkenyl group; Ri is nydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmιdazolme, and are eitner unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 116. The method of claim 115 where , when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 117. Tne method of claim 115, wherem the compound is 118. The method of claim 115, wherem the bowel disorder is colitis. 119. The method of claim 115, wherem the bowel disorder is Crohn's disease. 120. A method of treating a cardiovascular disorder m an anima. comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, proαrug, metabolite, stereoisomer, or mixtures thereof; wherein: 1 represents the atoms necessary to form a fuseα 5- tc 5-membered, aromatic or non-aromatic, carbocyclic or N-contammg neterocyclic ring, wherem Y and any heteroatom (s ) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selecteα from the group consisting of and wnerem R is nyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , P 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidine, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyx, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, nydroxy, carboxy, carcony_, ammo, amido, cyano, isocyano, nitro, nitroso, n trilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, nalo, haloalkyl, trifluoromethyl, aralkyl and aryl. 121. The method of claim 120 wherem, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l f R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 122. The method cf claim 120, wnerem the comccunα m 123. The method of claim 120, wherem the cardiovascular disorder is coronary artery disease, myocardial infarction, angma pectoris, cardiogemc shock and cardiovascular tissue damage. 124. A method of treating septic shock an animal O 99/59973 comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherein: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-containing heterocyclic ring, wherein Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-interfering alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-position of ring Y and is -C00R 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherein R' is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 125. The method of claim 124, wherem when Y is a fused, 6-membered, aromatic carbocyclic ring, and R 1 , R 2 , R 3 , and R 4 are each hydrogen, X is not a -COOH group. 126. The method of claim 124, wherem the compound is 127. The method of claim 124, where the type of septic shock is endotoxic shock. 128. A method of treating cancer m an animal comprising administering to said animal an effective amount of a compound of formula I : or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -C00R 5 or a substituted or unsubstituted moiety selected from the group consisting of , and , where R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cyclo- alkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdine, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alky_, a_.enyl, alkoxy, phenoxy, benzyloxy, cycloa_kyi, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhyαryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 129. The method of claim 128 wherem, when Y is a fused, 6-mempered, aromatic carbocyclic ring, and R l r R 2 , R 3 ana R 4 are eacn hydrogen, X is not a -COOH group. 130. Tne method of claim 128, wherem tne compounα is 131. The method of claim 128, wherem the cancer is selected from the group consisting of ACTH-producmg tumors, acute lymphocytic leukemia, acute nonlymphocytic leukemia, cancer of the adrenal cortex, bladder cancer, brair cancer, breast cancer, cervix cancer, chronic lymphocytic leukemia, chronic myelocytic leukemia, coiorectal cancer, cutaneous T-cell lympnoma, endometrial cancer, esopnageal cancer, Ewing ' s sarcoma, gallblaααer cancer, hairy cell leukemia, head & neck cancer, Hoαgkin's lympnoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/or non-small cell) , malignant peritoneal effusion, malignant pleural effusion, melanoma, mesotnelioma, multiple myeloma, neuroblastoma, non- Hodg-cm's lymphoma, osteosarcoma, ovary cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penis cancer, retinoblastoma, skm cancer, soft-tissue sarco m a, squamous cell carcinomas, stomach cancer, testicular cancer, thyroid cancer, trophoblastic ~eop_asms, cancer of the uterus, vaginal cancer, cancer of the Vulva ana ilm's tumor. 132. The method of claim 128, wherem said pharmaceutical composition is in a carrier comprising a biodegradable polymer. 133. The method of claim 132, wherem the bioαegradable polymer carrier is m the form of a soxid implant . 134. The method of claim 132, wherem the bioαeαradable polymer releases the compound cf formu_a I over a prolonged period of time. 135. A method of radiosensitizmg tumor cells comprising administering an effective amount of a compound of formula I : or a pnarmaceuticaily acceptable salt, hydrate, ester, solvate, proαrug, metabolite, stereoisomer, or mixtures thereof; wherem: _. represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, caroocyclxc or N-contammg heterocyclic ring, wnerem Y and any heteroatom (s ) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycioalkyl or cycloalkenyl group; i is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyi, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hyαroxy, carboxy, carbonyl, ammo, amiαo, cyano, isocyano, nitro, nitroso, n_trxlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 136. The method of claim 135 wherem, when Y is a fused, 6-memoered, aromatic carbocyclic ring, and R l r R 2 , R 3 ano R 4 are each hydrogen, X is not a -COOH group. 137. The method of claim 135, wherem the compound is 138. The method of claim 135, wherem said tumor cells are selected from tne group consisting of ACTπ- producing tumors, acute lymphocytic leukemia, acute nonlymdhocytic leukemia, cancer of the adrenal cortex, bladder cancer, bram cancer, breast cancer, cervix cancer, chronic lymphocytic leukemia, chronic myelocytic leukemia, colorectal cancer, cutaneous T-cell lymphoma, endometπa ^ cancer, esophageai cancer, Ewing ' s sarcoma, gallbladder cancer, hairy cell leukemia, head & neck cancer, Hodgkm's lymphoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/cr non-small cell,, malignant peritoneal effusion, malignant pleural effusion, melanoma, mesothelioma, multiple myeloma, neuroblastoma, non-Hodgkm ' s lymphoma, osteosarcoma, ovary cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penis cancer, retinoblastoma, skm cancer, soft-tissue sarcoma, squamous cell carcinomas, stomacn cancer, testicular cancer, thyroid cancer, tropnoblastic neoplasms, cancer of the uterus, vaginal cancer, cancer of the vulva and Wilm's tumor. 139. The method of claim 135, wnerem said pharmaceutical composition is in a carrier compnsmg a biodegradable polymer. 140. The method of claim 139, wherem the biodegradable polymer carrier is m the form of a solid implant . 141. The method of claim 139, wherem the biodegradable polymer releases the compound cf forimm I over a prolonged period of time. 142. A process of making the compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Ϊ represents the atoms necessary to form a fused 5- to 6- membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wnerem Y and any heteroatom (s ) therein are unsubstituted or independently substituted by at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, benzyl or aryl; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherein R 7 is hydrogen or alkyl, alkenyl, cycloalkyl or cyc oalkenyl, itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalky_ or cycloalkenyl group; Ri is nydrogen or alkyl, alkenyl, cycloalkyl or cycloalkenyl, itself either unsubstituted or substituted with an alkyl, alkenyl, cycloaxkyi or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, benzyl, aryl, ammo, hydroxyl, 1-pιperazιne, 1-pιperιdme, or 1-ιmιdazolme, either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hyαroxy, carooxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyx and aryl; provided that, when Y is a fuseα, 6-memoered, aromatic carbocyclic ring, and R l r R 2 , R 3 , and R 4 are each hydrogen, X is not a -COOH group; comprising the step of contacting an intermediate of III with a -COOR 5 radical or a substituted or unsubstituted radical selected from the group consisting of: and wherem R is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; and 'halo" is chloro, bromo or iodo moiety, 143. The process of claim 142 wnerem said R 5 is hydrogen or methyl. 144. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof, wherein the compound of formula I is present m an amount that is effective for treating ischemia; ana wherem: Y represents the atoms necessary to form a fuseα 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituted w th at least one non-interfering alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carooxy or halo substituent; X is at the 1-position of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selecteα from the group consisting of and wherem R is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alky_, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitnlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and ary . 145. The composition of claim 144, wherem when Y is a fused, 6-membered, aromatic, carbocyclic ring, and R l r R 2 , R 3 , and R 4 are each hydrogen, X is not a -COOH group. 1 ^ 6 . The compos i"; ;n o] .aim 4 wnerem the compounα is _47. A method of treating ischemia in an anima. comprising administering to said animal an effective amou-t of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: _ represents the atoms necessary to form a fuseα 5- to 6-membereα, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s ) therein are unsubstituted or independently substituted ith at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carooxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selecteα from the group consisting of and wherem ^ is nyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; Ri is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or I-ιmιdazoiιne, and are either unsubstituted or substituted with a moiety selected from the group consisting of alky_, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitriio, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, haio, haloalkyl, trifluoromethyl, aralkyl and aryl. 148. The method of claim 147, wherem when Y is a fused, 6-membered, aromatic, carbocyclic ring, and R l r R 2 , R 3 , and R 4 are each hydrogen, X is not a -COOH group. 149. The method of claim 147, wnerem the compound is 150. A method of radiosensitizmg tumor cells in an animal comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contammg heterocyclic ring, wherem Y and any heteroatom (s) therein are unsubstituted or independently substituteα itn at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-posιtιon of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selecteα from the group consisting of O 99/59973 and wherem R is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloaikyl or cycloalkenyl group; i is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloamyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, al^y ^ , alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazιne, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, mtrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and ary_. 151. The method of claim 150 wherem, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 ana R 4 are each hydrogen, X is not a -COOH group. 152. The method of claim 150, wherein the compound is 153. The method of claim 150, wherem the tumor cells are selected from the group consisting of ACTH-producmg tumors, acute lymphocytic leukemia, acute nonlymphocytic leukemia, cancer of the adrenal cortex, bladder cancer, bram cancer, breast cancer, cervix cancer, chronic lympnocytic leukemia, chronic myelocytic leukemia, colorectal cancer, cutaneous T-cell lymphoma, endometrial cancer, esophageal cancer, Ewmg's sarcoma, gallbladder cancer, hairy cell leukemia, head & neck cancer, Hodgkm's lymphoma, Kaposi's sarcoma, kidney cancer, liver cancer, lung cancer (small and/or non-small cell), malignant peritoneal effusion, malignant pleural effusion, melanoma, mesothelioma, multiple myeloma, neuroblastoma, non- Hodgkm 's lymphoma, osteosarcoma, ovary cancer, ovary (germ cell) cancer, prostate cancer, pancreatic cancer, penis cancer, retinoblastoma, skm cancer, soft-tissue sarcoma, squamous cell carcinomas, stomach cancer, testicular cancer, thyroid cancer, trophoblastic neoplasms, cancer of the uterus, vaginal cancer, cancer of the vulva and ilm's tumor. 154. The method of claim 150, wherem said pharmaceutical composition is m a carrier comprising a biodegradable polymer. 155. The method of claim 154, where the biodegradable polymer carrier is in the form of a solid implant. 156. The method of claim 154, wherem the biodegradable polymer releases the compound of formula I over a prolonged period of time. 157. A method to extend the lifespan and proliferative capacity of cells in an animal comprising administering to said animal an effective amount of a compound of formula I: or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherem: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-contaming heterocyclic ring, wherein Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-mterfermg alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-position of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of , and , wherem R is hyαrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 1 is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituteα or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R s are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- piperidme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitrilo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 158. The method of claim 157 wherein, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 159. The method of claim 157, wherem the compound is 160. The method of claim 157, wherem said method is used to treat a disease or disease conditions induced or exacerbated by cellular senescence. 161. The method of claim 160, wherem said disease is a disease selected from the group consisting of skm aging, Alzheimer's disease, atherosclerosis, osteoarthritis, osteoporosis, muscular dystrophy, age- related macular degeneration, immune senescence, ana AIDS. 162. The method of claim 157, wherem said pharmaceutical composition is m a carrier comprising a biodegradable polymer. 163. The method of claim 162, wherem the biodegradable polymer carrier is in the form of a solid implant . 164. The method of claim 162, wherem the biodegradable polymer releases the compound of formula I over a prolonged period of time. 165. A method of altering gene expression of senescent cells comprising administering a compound of formula I : O 99/59973 or a pharmaceutically acceptable salt, hydrate, ester, solvate, prodrug, metabolite, stereoisomer, or mixtures thereof; wherein: Y represents the atoms necessary to form a fused 5- to 6-membered, aromatic or non-aromatic, carbocyclic or N-containing heterocyclic ring, wherein Y and any heteroatom (s) therein are unsubstituted or independently substituted with at least one non-interfering alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, carboxy or halo substituent; X is at the 1-position of ring Y and is -COOR 5 or a substituted or unsubstituted moiety selected from the group consisting of and wherein R' is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R x is hydrogen, alkyl, alkenyl, cycloalkyl or cycloalkenyl, and is itself either unsubstituted or substituted with an alkyl, alkenyl, cycloalkyl or cycloalkenyl group; R 2 , R 3 , R 4 and R 5 are independently hydrogen, alkyl, alkenyl, cycloalkyl, cycloalkenyl, aralkyl, aryl, ammo, hydroxyl, 1-pιperazme, 1- pipeπdme, or 1-ιmιdazolme, and are either unsubstituted or substituted with a moiety selected from the group consisting of alkyl, alkenyl, alkoxy, phenoxy, benzyloxy, cycloalkyl, cycloalkenyl, hydroxy, carboxy, carbonyl, ammo, amido, cyano, isocyano, nitro, nitroso, nitπlo, isonitrilo, immo, azo, diazo, sulfonyl, sulfoxy, thio, thiocarbonyl, sulfhydryl, halo, haloalkyl, trifluoromethyl, aralkyl and aryl. 166. The method of claim 165 wherein, when Y is a fused, 6-membered, aromatic carbocyclic ring, and R l r R 2 , R 3 and R 4 are each hydrogen, X is not a -COOH group. 167. The method of claim 165, wherem the compound is 168. The compounds, compositions, methods and processes described herein.

Inventors: LI JIA-HE, ZHANG JIE, LI, JIA-HE, ZHANG, JIE
Applicants: GUILFORD PHARM INC, GUILFORD PHARMACEUTICALS INC.
Application year: 1998
Main classification: C07D215
IPC codes: A61K9, A61K31, A61P1, A61P3, A61P9, A61P13, A61P19, A61P21, A61P25, A61P27, A61P29, A61P35, A61P43, C07C233, C07C235, C07D209, C07D215, C07D217, C07D221, C07D239, C07D257, C07D261, C07D307, C07D309, C07D333, C07D495