bluuebunny/crossref_metadata_2025 huggingface dataset:
The Disposition of the Tolcapone 3-O-Methylated Metabolite is Affected by the Route of Administration in Rats
Authors: Funaki Tomoo , Onodera Hideko , Ushiyama Naomi , Tsukamoto Yuko , Tagami Chieko , Fukazawa Hideo , Kuruma Isami
Published: April 2011

Catechol-O-methyltransferase (COMT) catalyses the transfer of the methyl group from S-adenyl-l-methionine (SAM) to one of the hydroxy groups of a catechol, usually the hydroxy group in position 3. COMT is present mainly in a soluble form (S-COMT) in the cytosol, but a small fraction is bound to cell membranes (MB-COMT). MB-COMT has higher affinity for the catechol substrate than does S-COMT by a factor of > 10, and high MB-COMT activity is observed in the intestinal muscle layer. The present study investigates the effect of the administration route on the disposition of the tolcapone 3-O-methylated metabolite following intravenous and oral tolcapone administration in rats. Tolcapone is a substrate for COMT although the 3-O-methylated metabolite produced has no pharmacological actions. The 3-O-methylated metabolite was eliminated very slowly following oral administration of tolcapone, and its concentration approached a plateau level, which was in contrast to the situation following intravenous administration of tolcapone. It is thought that the oral dose of tolcapone receives a high exposure to MB-COMT in the intestinal muscle layer during its absorption, and tolcapone seems to form a complex with MB-COMT having a high affinity constant (i.e. a very low Ki). The fraction of the intravenous dose of tolcapone metabolized to the 3-O-methylated metabolite at 10 mg kg−1 was 2·6%, whereas those of the oral doses, which were corrected by the bioavailability, were 5·4% for 20 mg kg−1 and 2·7% for 40 mg kg−1.
Enhanced rectal absorption of itazigrel formulated with polysorbate 80 micelle vehicle in rat: role of co-administered esterase
Authors: Yamamoto Ken , Shah Ashok C , Nishihata Toshiaki
Published: April 2011

We investigated the effect of esterase on rectal absorption in the rat of itazigrel using polysorbate 80 (PS-80) micelle as a vehicle to overcome the poor aqueous solubility of itazigrel. The itazigrel formulation prepared with PS-80 increased the absorption compared with a 0·25% carmellose sodium suspension, probably by supplying the itazigrel solute to keep a high concentration at the epithelial surface. When esterase was co-administered with the formulations containing PS-80, the absorption of itazigrel from rat rectum was accelerated further, by rapid release of itazigrel from the micelle vehicle after enzymatic degradation of the PS-80 micelle.
Menthol and Related Cooling Compounds
Authors: Eccles R
Published: April 2011

Menthol and related cooling compounds such as ‘coolant agent 10’, are widely used in products ranging from common cold medications to toothpastes, confectionery, cosmetics and pesticides. The review brings together a range of information on production and chemistry of menthol, and its metabolism, mechanism of action, structure-activity relationships, pharmacology and toxicology. In particular, the coolant action and carminative actions of menthol are discussed in terms of actions on calcium conductance in sensory nerves and smooth muscle. The actions of menthol on the nose, respiratory reflexes, oral cavity, skin and gastrointestinal tract are reviewed.
The Distribution of an Intranasal Insulin Formulation in Healthy Volunteers: Effect of Different Administration Techniques
Authors: Newman S P , Steed K P , Hardy J G , Wilding I R , Hooper G , Sparrow R A
Published: April 2011

The initial deposition pattern in the nasal passages and subsequent clearance of an insulin formulation labelled with 99mTc-human serum albumin have been determined in 12 healthy male volunteers. Four different administration modes from a novel aqueous spray device were compared, involving delivered volumes of 80–160 μL, and with either gentle or vigorous inhalation while firing the device. The entire dose was deposited in the nasal cavity, and no significant radioactivity was deposited in the lungs. A mean 25–33% of the radiolabel remained in the nose after 4h. A significantly smaller area of the nasal mucosa was covered by the smallest (80 μL) bolus, but subsequent clearance rates did not vary significantly with mode of administration. Blood glucose levels fell after administration of the insulin formulation, but no serious episodes of hypoglycaemia occurred.
Subcellular Distribution of Proteolytic Activities Degrading Bioactive Peptides and Analogues in the Rat Small Intestinal and Colonic Enterocytes
Authors: Bai Jane P F
Published: April 2011

The objective of this study was to compare, in rat small intestinal and colonic enterocytes, subcellular distributions of activities degrading the large peptides, neurotensin, acetylneurotensin (8–13), GRF(1–29)NH2 (human growth hormone releasing factor fragment), (desNH2Tyr1,D-Ala2,Ala15)-GRF(1–29)NH2, insulin, and insulin B-chain. Proteolytic activities degrading individual peptides in the 10000-g pellet, rich in intracellular organelles, 27000-g pellet, rich in brush-border membrane, 100000-g pellet, and 100000-g supernatant, rich in cytosol, were determined and compared for both the small intestine and colon. In colonic fractions, the cytosol had highest activity (g protein)−1 degrading three out of four peptides tested, while in small intestinal fractions, the 27000-g pellet had the highest activity (g protein)−1, degrading four out of five peptides tested. In both small intestine and colon, the cytosol had a higher percentage of total proteolytic activity degrading each of the above polypeptides and the highest insulin-degrading activity (g protein)−1. The results suggest that at pH 7·5, proteolytic activities (g protein)−1 in the fraction of subcellular organelles are much lower than those in cytosol and that cytosolic proteolytic activities degrading polypeptides and analogues are significant.
The Stimulative Effect of Diffusion Potential on Enoxacin Uptake across Rat Intestinal Brush-border Membranes
Authors: Hirano Takeshi , Iseki Ken , Miyazaki Shozo , Takada Masahiko , Kobayashi Michiya , Sugawara Mitsuru , Miyazaki Katsumi
Published: April 2011

Evidence of a membrane potential dependence for enoxacin uptake by rat intestinal brush-border membrane vesicles has been found. The transient overshooting uptake of enoxacin disappeared in the voltage-clamped brush-border membrane vesicles in the presence of an outward H+-gradient. Momentary dissipation of the H+-gradient itself by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) did not affect the uptake of enoxacin. In contrast, enoxacin uptake was depressed by an interior positive K+-diffusion potential induced by valinomycin. Furthermore, not only the outward H+-gradient but also an inward Cl−-gradient caused a stimulating effect on enoxacin uptake, and the stimulation by the Cl−-gradient was dissipated by using voltage-clamped membrane vesicles. These results indicate that enoxacin transportation across the brush-border membrane is dependent on the ionic diffusion potential. On the other hand, neither Gly-Gly nor guanidine had any effect on enoxacin uptake by the membrane vesicles in the presence of an inward (for Gly-Gly) or outward (for guanidine) H+-gradient as a driving force for each transport system. Therefore, it seems that enoxacin transport through the intestinal epithelia does not participate in the carrier-mediated transport systems for Gly-Gly and guanidine.
The Inhibitory Effects of Cephalosporin and Dipeptide on Ceftibuten Uptake by Human and Rat Intestinal Brush-border Membrane Vesicles
Authors: Sugawara Mitsuru , Toda Takaki , Kobayashi Michiya , Iseki Ken , Miyazaki Katsumi , Shiroto Hiroshi , Uchino Jun-Ichi , Kondo Yukifumi
Published: April 2011

The types of inhibitory effects caused by compound V (an analogue of ceftibuten) and alanylproline (dipeptide) on the uptake of ceftibuten by brush-border membrane vesicles (BBMV) prepared from human and rat small intestine were analysed. In the presence of an inward H+-gradient, the initial uptake rate of ceftibuten by both human and rat intestinal BBMV was concentration-dependent with apparent Km and Vmax values of 0·35 min and 2·052 nmol (mg protein)−1 min−1 for human BBMV, and 0·50 mm and 3·056 nmol (mg protein)−1 min−1 for rat BBMV, respectively. For both human and rat BBMV, kinetic analysis by Dixon and Lineweaver–Burk plots demonstrated that the uptake of ceftibuten was competitively inhibited by compound V, whereas inhibition by alanylproline was noncompetitive or partially competitive. These results suggest that there is a stereospecific transport system which is common to ceftibuten and compound V, and that this system is not identical to the carrier system for the dipeptide, alanylproline.
Use of Cultured Human Neuroblastoma Cells in Rapid Discovery of the Voltage-gated Potassium-channel Blockers
Authors: Toral Joyce , Hu William , Yi Lynda , Barrett James E , Sokol Patricia T , Ziai M Reza
Published: April 2011

Depolarization of human neuroblastoma cells by high concentrations of extracellular potassium ions, leads to the activation of the voltage-gated potassium channels. The activity of such potassium channels can be effectively and rapidly monitored by tracking the efflux of 86Rb from pre-loaded target cells in response to the depolarizing stimulus. The inclusion of compounds with unknown activity in the assay medium, can result in the identification of novel blockers of the voltage-gated potassium channels. Since this functional assay is performed in 96-well microtitre plates, it represents a rapid and high-volume primary screening method for the detection and identification of the voltage-gated potassium-channel blockers, which may have therapeutic utility in several indications including memory degeneration and cardiac arrhythmias.
Manganese Ions Induce Tonic Contraction after Relaxation in a High-K+ Medium in Ileal Longitudinal Smooth Muscle of Guinea-pig
Authors: Nasu T , Murase H , Shibata H
Published: April 2011

In ileal longitudinal muscle 5Mm Mn2+ inhibited completely the K+ (60 Mm)-induced tonic tension to the base line; however, the tension progressively increased to above the level of original tonic response evoked by K+ after 3 h in the presence of Mn2+. Tetrodotoxin (5 × 10−5 m) had no influence on the tension development in the presence of Mn2+ in the high-K+ medium. Mn2+ also increased the tension in a high-K+, Ca2+-free medium. The Ca2+ antagonist, gallopamil (10−6 m) inhibited the development of tension in the presence of Mn2+ in the high-K+ medium. The 45Ca uptake determined by the lanthanum method remained unchanged from control levels after 3 h of the 5 Mm Mn2+ application in the high-K+ medium in spite of the development of the tension. The manganese uptake in the high-K+ medium, increased in accordance with the increase of duration of 5 Mm Mn2+ application. Gallopamil inhibited manganese uptake in the high-K+ medium. These results suggest that Mn2+ firstly reduces K+-induced tension by inhibition of Ca2+ influx; subsequently, Mn2+ ions accumulate in the intracellular compartments through voltage-operated Ca2+ channels and may activate contractile proteins in the ileal muscle.
Effect of Aminoethylpyrroles on Carrageenan-induced Inflammation and on Lipid Peroxidation in Rats: Some Structural Aspects
Authors: Demopoulos Vassilis J , Rekka Eleni
Published: April 2011

Nine 3-(2-aminoethyl)pyrrole derivatives were investigated as anti-inflammatory agents in the carrageenan-induced rat paw oedema model and as antioxidants in the non-enzymatic lipid peroxidation assay. It was found that the derivatives which were substituted with a p-toluenesulphonyl group exhibited considerable anti-inflammatory activity and some also showed antioxidant properties. However, the presence of a p-toluenesulphonyl group did not invariably lead to activity. A structural feature which was essential for both activities was the aminoethyl side chain. Although a relationship between the antiinflammatory and the antioxidant activities was not apparent, the combination of these properties could be useful.
Effects of In-vivo Administration of Taurine and HEPES on the Inflammatory Response in Rats
Authors: Stapleton Philip P , Mahon Tara M , Nowlan Peter , Bloomfield Frederick J
Published: April 2011

The effect of in-vivo administration of N-2-hydroxyethylpiperazine-N’-2-ethane sulphonic acid (HEPES) and taurine on rat paw oedema and reactive oxidant production was examined. Carrageenan-induced paw oedema was attenuated following intraperitoneal injection of HEPES. Chemiluminescence production by isolated peripheral blood mononuclear cells (PBMC) was reduced in HEPES-treated rats. Taurine-treated rats did not exhibit attenuation of paw oedema using subcutaneous or intraperitoneal administration but intracerebroventricular administration produced a significant reduction at a dosage of 4·0 μmol. No reduction in chemiluminescence production was observed by PBMC using subcutaneous or intraperitoneal administration of taurine, but intracerebroventricular administration produced a significant reduction at a dosage of both 0·4 and 4·0 μmol. Intravenous injection of [14C]HEPES or [3H]taurine demonstrated rapid clearance with a significantly longer half-life of HEPES compared with taurine. These results support previous reports of anti-inflammatory activity of taurine when administered centrally. The lack of anti-inflammatory effect when taurine was administered subcutaneously or intraperitoneally may be a consequence of rapid distribution or clearance. The greater anti-inflammatory effects of HEPES compared with taurine may be due to its slower distribution or clearance in-vivo.
Binding Potency of 6-Nitroquipazine Analogues for the 5-Hydroxytryptamine Reuptake Complex
Authors: Mathis Chester A , Taylor Scott E , Enas Joel D , Akgün Eyup
Published: April 2011

The in-vitro inhibition constants (Ki) of nine structural analogues of the potent 5-hydroxytryptamine (5-HT)-uptake inhibitor, 6-nitroquipazine, were determined to assess the structure-affinity relationship of these derivatives. The goal of these studies was to determine those positions on 6-nitroquipazine that could be derivatized without significantly decreasing the affinity of the drug for the binding site, so that radiolabels such as 123I, 76Br or 18F might be appended for in-vivo imaging studies of the 5-HT reuptake system. Using bromine as a steric probe, the rank order of potency of bromine-substituted 6-nitroquipazine analogues for inhibiting the binding of [3H]paroxetine to the 5-HT reuptake binding site was: 8-<3-<7-<4-<5-bromo. The in-vitro equipotent molar ratio (EPMR, Ki (analogue)/Ki(6-nitroquipazine)) of the 5-bromo analogue was 0·57, indicating that this analogue had greater affinity for the 5-HT reuptake complex than 6-nitroquipazine. Derivatization at the 5-position with fluorine and iodine also resulted in potent compounds with EPMR values of 1·1 and 0·83, respectively. Substitution of quipazine with bromo, cyano, and formyl groups at the 6-position produced less potent compounds than the 6-nitro group. Based upon the high affinities of the 5-bromo-, 5-fluoro- and 5-iodo-6-nitroquipazines for the 5-HT reuptake complex, these compounds are candidates for radiolabelling for in-vivo studies of the 5-HT reuptake site.
Analgesic Effects of Callus Culture Extracts from Selected Species of Phyllanthus in Mice
Authors: Santos Adair R S , Filho Valdir C , Niero Rivaldo , Viana Ana M , Moreno Fabio N , Campos Maria M , Yunes Rosendo A , Calixto Joóo B
Published: April 2011

The aim of this study was to evaluate the analgesic effect of the methanolic extract from callus culture of Phyllanthus tenellus, P. corcovadensis and P. niruri in several models of pain in mice. The extracts (medium containing 2,4-dichlorophenoxyacetic acid) of P. corcovadensis, P. niruri and P. tenellus (3–90 mg kg−1, i.p.) caused graded inhibition of abdominal constrictions induced by acetic acid (0·6%), with ID50 (i.e. dose that reduced response of control by 50%) values of about 30, 19 and >30 mg kg−1, respectively. The extract of callus of Phyllanthus obtained in indole-3-butyric acid and indole-3-acetic acid media (3–90 mg kg−1, i.p.) caused a similar analgesic effect. In the formalin test, the extract of P. tenellus obtained in indole butyric acid medium (3–100 mg kg−1, i.p.) inhibited only the second phase of formalin-induced pain with an ID50 value of about 100 mg kg−1. Both the indole acetic acid and indole butyric acid methanolic extracts of P. tenellus and P. corcovadensis (10–100 mg kg−1, i.p.) dose-dependently inhibited both phases of formalin-induced pain (ID50 values for the second phase were approx. 100 and 52 mg kg−1, respectively). However, the extract of callus from Phyllanthus failed to affect formalin-induced paw oedema, as well as the response to radiant heat in the tail-flick test. In addition, the analgesic effect of morphine, but not the analgesic effects caused by Phyllanthus callus extract, was fully antagonized by naloxone. Preliminary phytochemical analysis revealed the presence of several compounds having no apparent relationship with alkaloids or flavonoids but showing the presence of phenols. These results indicate that, similar to previous reported data from the extract of P. corcovadensis, the methanolic extracts of callus culture of P. niruri, P. corcovadensis and P. tenellus exhibit potent analgesic properties against neurogenic and inflammatory pain that seem to be unrelated to the activation of opioid mechanisms.
Properties of the binding sites of [3H]9-methyl-7-bromoeudistomin D in bovine aortic smooth muscle microsomes
Authors: Adachi Masatoshi , Fang Yano-Il , Yamakuni Toru , Kobayashi Junichi , Ohizumi Yasushi
Published: April 2011

[3H]9-Methyl-7-bromoeudistomin D ([3H]MBED), a powerful caffeine-like Ca2+ releaser, binds to the caffeine binding site of terminal cisternae of skeletal muscle sarcoplasmic reticulum and activates Ca2+-induced Ca2+ release. Properties of the binding site of [3H]MBED were investigated in aortic smooth muscle. The specific activity was higher in microsomes than in other fractions. [3H]MBED binding sites in smooth muscle microsomes were of a single class with a high affinity (KD 50 Nm), comparable with that in skeletal muscle sarcoplasmic reticulum. Caffeine competitively inhibited [3H]MBED binding, indicating MBED shares the same binding site with caffeine. Solubilization and fractionation of the microsomes gave two fractions of [3H]MBED binding activities. These results suggest that, in smooth muscle, there are multiple binding sites of [3H]MBED and caffeine, which might correspond to different pharmacological actions of caffeine on smooth muscle. Therefore, [3H]MBED, which binds to the different binding sites of caffeine, is useful as a probe for investigation of the actions of caffeine at the molecular level.
Casein as a Carrier Matrix for 5-Fluorouracil: Drug Release from Microspheres, Drug-protein Conjugates and In-vivo Degradation of Microspheres in Rat Muscle
Authors: Latha M S , Jayakrishnan A , Rathinam K , Mohanty M
Published: April 2011

Glutaraldehyde cross-linked casein microspheres were loaded with 5-fluorouracil (5-FU) from concentrated aqueous solutions of the drug after the microspheres were synthesized and cleaned. In-vitro release of the drug was examined in phosphate buffer in the absence and in the presence of protease at 37°C. Drug release data showed that only about 20% of the drug is released in the absence of protease even after 5 days, while digestion of the matrix with protease released the entrapped drug completely in about 24 h. A protein-drug conjugate was synthesized via carbamoyl linkage using 6-(5-FU-1-yl)hexyl isocyanate and the drug release was examined in phosphate buffer at 37°C. Release from the protein-5-FU conjugate was slower compared with the release from microspheres in the presence of protease. Implantation of placebo microspheres of different cross-linking densities in the gluteal muscle of rats showed no adverse tissue reactions over a one-year period. Histopathological examination of the tissues containing injected microspheres suggested that the biological life of casein microspheres in muscle is about 6 months, which is three times that of cross-linked albumin microspheres.
In-vivo and In-vitro Targeting of a Murine Sarcoma by Gelatin Microparticles Loaded with a Glycan (PS1)
Authors: Lou Yan , Groves Michael J , Klegerman Melvin E
Published: April 2011

PS1, a complex polysaccharide derived from Mycobacterium bovis (Bacillus Calmette-Guérin, BCG) with considerable antitumour activity in-vivo, was loaded onto gelatin microparticles (mean diam. 1·45 μm) at a level shown to not produce the burst effect often seen with drug-loaded micro-particulate systems. In-vitro dissolution experiments had demonstrated a sustained-release behaviour, with a half-life of approximately 8 h for what is an extremely water-soluble material. These PS1/gelatin systems had no measurable cytotoxicity against an S180 murine sarcoma cell in-vitro although fibronectin-mediated targeting of the microparticles for the tumour cells could be demonstrated. Injection into mice, with the S180 cells, of PS1 solutions or suspensions of PS1-loaded gelatin microparticles resulted in almost identical dose-related suppression for the tumour cell growth. When injected at intervals following injection of the tumour cells, however, for a period of 24–48 h there was a relatively enhanced activity of the formulated PS1, compared with the aqueous solution, after which both formulated and unformulated material became progressively less effective.
Absorption of Organic Anions as Model Drugs Following Application to Rat Liver Surface In-vivo
Authors: Nishida Koyo , Sato Norihito , Sasaki Hitoshi , Nakamura Junzo
Published: April 2011

Absorption of organic anions (phenol red, bromphenol blue and bromosulphonphthalein) has been studied after their application to rat liver surface in-vivo, employing a cylindrical glass cell (i.d. 9 mm, area 0·64 cm2). Each drug appeared gradually in the blood with the peak level at about 1 h, after which its concentration declined slowly. Absorbed model drug was efficiently excreted into the bile. These observations appear to indicate the possibility of drug absorption from liver surface membrane. Absorption of model drugs was estimated to be more than 59% in 6 h. The biliary recovery and metabolism of phenol red did not change as compared with that after intravenous administration.
Liposome and Multiple Emulsion Formulations Augment the Anticalcifying Efficacy of Phosphocitrate in a Cutaneous Calcergy Model
Authors: Kamperman Harold , Sallis John D
Published: April 2011

The anticalcifying agent phosphocitrate was incorporated into phosphatidylcholine/cholesterol liposomes by reverse-phase evaporation. The compound was entrapped to the extent of 11.6% (mol mol−1 of lipid) and the liposomes exhibited prolonged retention of the compound when incubated with rat plasma.

Phosphocitrate's ionic contribution in solution adversely influenced the encapsulation efficiency but improvements were made through ion-pairing with the quaternary ammonium detergent cetrimide, or with the inclusion of stearylamine in the lipid phase. The liposomal dose that could be practically administered in-vivo was restricted to 2.5 mg phosphocitrate kg−1 day−1. The formulation of a multiple emulsion preparation of phosphocitrate, however, offered an alternative delivery mode permitting infrequent dosing to be successfully investigated. In a rat calcergy model, both vehicles effectively reduced the formation of induced subcutaneous calcified plaques at doses for which the phosphocitrate salt alone was inactive.

The current formulations demonstrate that the therapeutic efficacy of phosphocitrate can be markedly improved through an appropriately designed drug delivery system, signalling a new approach for the future therapeutic application of this compound.
Liposome-incorporated Dexamethasone Palmitate Inhibits In-vitro Lymphocyte Response to Mitogen
Authors: Benameur H , Latour N , Schandene L , Van Vooren J P , Flamion B , Legros F J
Published: April 2011

The use of liposomes for the pulmonary delivery of corticosteroid is an area that is under active investigation. We have recently developed a novel liposomal corticosteroid preparation based on the incorporation of dexamethasone palmitate (DMP) within the bilayer of small unilamellar vesicles (SUVs) made of egg yolk phosphatidylcholine (EPC) and cholesterol; molar ratio EPCC: cholesterol: DMP, 4:3:0.3.

In the present study, the biological activity of DMP-SUVs was evaluated using the lymphocyte transformation test with peripheral blood mononuclear cells (PBMCs) and a δ-interferon production assay. Results showed that DMP-SUVs (but not empty SUVs) inhibited [3H]thymidine uptake and δ-interferon production by concanavalin A-stimulated PBMCs by 94 and 96%, respectively, at a concentration corresponding to 10−6 M dexamethasone. The inhibition by DMP-SUVs was found to require a 24-h pre-incubation with unstimulated PBMCs, suggesting that interaction of SUVs with lymphocytes may be altered by mitogen stimulation.

We conclude that our DMP liposomal preparation is biologically active and may be considered a promising alternative to conventional local glucocorticoid therapy.
Effects of Chronic Nitric Oxide Synthase Inhibition on TNB-induced Colitis in Rats
Authors: Pfeiffer C J , Qiu B S
Published: April 2011

Nitric oxide (NO) synthesis is increased in ulcerative colitis, but the role of NO in colitis is poorly understood. The present study employed NW-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, in rats to evaluate the effect of NO on 2,4,6-trinitrobenzenesulphonic acid (TNB)-induced colitis.

L-NAME solutions were placed in subcutaneous, osmotic mini-pumps which continuously released L-NAME at 0.042, 0.208, 0.417, or 1.667mgkg−1 h−1. L-NAME dose-dependently enhanced lesions in TNB-induced colitis. The two higher doses of L-NAME significantly increased colonic mucosal damage, although there was slight, nonsignificant reduced lesion formation with the lowest dose of L-NAME, 0.042 mgkg−1 h−1. A single dose of L-NAME at 100 mgkg−1 subcutaneously injected daily in TNB-treated rats also increased lesions, and these ulcerogenic actions of L-NAME were reversed by L-arginine but not by D-arginine (both at 500mgkg−1, s.c). Only the highest dose of L-NAME (mini-pump) significantly depressed myeloperoxidase (MPO) activity. Faecal occult bleeding showed a close relationship with severity of colitis.

These findings suggest that there may exist a balance between NO protective and aggressive effects. In TNB-induced colitis, antagonism of endogenous NO generation was intensified, whereas slight inhibition of NO synthesis reduced lesions. Variations in responses, related to timing or dose changes in L-NAME, may reflect the differences in inducible vs constitutive NO synthase isoforms.
Comparison of Behavioural Effects of Repeated Treatment with Methamphetamine plus Scopolamine and Methamphetamine Alone on Behavioural Sensitization and Conditioned Response
Authors: Yui Kunio , Miura Takao , Sugiyama Kimihito , Ono Mamoru , Nagase Moriharu
Published: April 2011

We investigated how repeated treatments with methamphetamine (4.0mgkg−1, i.p.) plus scopolamine (0.5mgkg−1, i.p.) and methamphetamine alone effected behavioural sensitization and conditioned response in rats.

Repeated methamphetamine plus scopolamine treatment induced a more progressive and enduring enhancement of focused stereotyped behaviour than repeated methamphetamine treatment. Stereotyped behaviour induced by methamphetamine plus scopolamine was reproduced by challenge injections of methamphetamine plus scopolamine, methamphetamine, and to a lesser extent by scopolamine challenges.

The methamphetamine plus scopolamine-sensitized rats were conditioned to a low frequency tone (300 Hz, 100 dB) associated with the drug state. They exhibited a conditioned response to pairings of the tone (conditioned stimulus) and placebo injections. However, they did not respond to the tone alone or the placebo injections alone.

The methamphetamine-sensitized rats failed to demonstrate any conditioning; only the repeated methamphetamine plus scopolamine treatment induced sensitization to the drug-associated tone. Pairings of exteroceptive conditioned stimulus-interoceptive unconditioned stimulus associations may provide an important source for conditioning to the tone associated with the drug state.

We conclude that behavioural sensitization may operate via a reciprocal balance between the dopaminergic and cholinergic inhibitory systems, in favour of a dopaminergic dominance. Conditioning to the drug-associated tone may be mediated via a reciprocal balance between the two transmitter systems.
857-860Anti-inflammatory Effect of Magnolol, Isolated from Magnolia officinalis, on A23187-induced Pleurisy in Mice
Authors: Wang Jih-Pyang , Ho Tsing-Fen , Chang Ling-Chu , Chen Chien-Chih
Published: April 2011

In the present study, A23187-induced pleurisy in mice was used to investigate the anti-inflammatory effect of magnolol, a phenolic compound isolated from Chinese medicine Hou p'u (cortex of Magnolia officinalis).

A23187-induced protein leakage was reduced by magnolol (10mgkg−1, i.p.), indomethacin (10mgkg−1, i.p.) and BW755C (30mgkg−1, i.p.). A23187-induced polymorphonuclear (PMN) leucocyte infiltration in the pleural cavity was suppressed by magnolol and BW755C, while enhanced by indomethacin. Like BW755C, magnolol reduced both prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels in the pleural fluid of A23187-induced pleurisy, while indomethacin reduced PGE2 but increased LTB4 formation. In the rat isolated peripheral neutrophil suspension, magnolol (3.7 μM) and BW755C (10 μM) also suppressed the A23187-induced thromboxane B2 (TXB2) and LTB4 formation.

These results suggest that magnolol, like BW755C, might be a dual cyclo-oxygenase and lipoxygenase inhibitor. The inhibitory effect of magnolol on the A23187-induced pleurisy is proposed to be, at least partly, dependent on the reduction of the formation of eicosanoids mediators in the inflammatory site.
Esters of L-Dopa: Structure-hydrolysis Relationships and Ability to Induce Circling Behaviour in an Experimental Model of Hemiparkinsonism
Authors: Brunner-Guenat Michele , Carrupt Pierre-Alain , Lisa Giuseppe , Testa Bernard , Rose Sarah , Thomas Kerrie , Jenner Peter , Ventura Paolo
Published: April 2011

A number of carboxylate esters of L-dopa, some of which are novel, were examined for their physicochemical and biological properties. A few esters of tyrosine and phenylalanine were included for comparison.

The compounds displayed great differences in their lipophilicity and stability towards chemical and enzymatic (human plasma) hydrolysis. Within subseries, relationships exist between structural properties and rate constants of chemical or enzymatic hydrolysis. In an experimental model of hemiparkinsonism (circling behaviour in rats), some of the L-dopa esters (the isopropyl, sec-butyl and 2-(tetrahydropyr-anyl)methyl esters) showed an activity distinctly greater than that of L-dopa, although the difference was not statistically significant.
Cytotoxicity, Cell Cycle Kinetics and Morphonuclear-induced Effects of Vinca Alkaloid Anticancer Agents
Authors: Pauwels Olivier , Kiss Robert , Pasteels Jean-Lambert , Atassi Ghanem
Published: April 2011

The effects of four Vinca alkaloids (vinblastine, vincristine, vindesine and vinorelbine) on three neoplastic cell lines (the MXT mouse mammary cell line and the T24 and J82 bladder cell lines) were studied at three biological levels, i.e. cell proliferation, cell cycle kinetics and morphonuclear characteristics. These effects were studied by means of digital cell image analysis on Feulgen-stained nuclei. The aim of the present work was to characterize the effects specifically induced by Vinca alkaloids as compared with those obtained previously with other pharmacological classes of anticancer drugs.

The results show that Vinca alkaloids inhibit the cell proliferation of neoplastic cell lines at a concentration of 10***-8 M except in the case of the J82 cell line, for which only a slowing down of cell proliferation was observed. Concerning the cell cycle kinetics, the results show that the Vinca alkaloids induce an accumulation of cells in the mitosis phase. This accumulation of mitotic cells was maximal after 15 h incubation in the presence of the drugs. A study of the morphonuclear-induced effects of Vinca alkaloids showed that the variance of the optical density (VOD) is strongly influenced by these Vinca alkaloids. The development of the VOD was parallel with the development of the percentage of mitosis; thus, the VOD enabled the Vinca alkaloid-induced effects to be specifically characterized from a morphonuclear point of view. On the other hand, the results show that the mean value of the variance of the optical density was very highly correlated (P < 0***.001) with the efficiency of the Vinca alkaloids in terms of cytotoxicity.

In clinical studies, the analysis of the development of this parameter would make it possible to assess the response to chemotherapy in the case of patients treated with Vinca alkaloids.
The Use of Gelatin Microparticles to Delay the Release of Readily Water-soluble Materials
Authors: Lou Yan , Groves Michael J
Published: April 2011

The adsorption of D-arabinose onto gelatin microparticles demonstrated a Langmuirian adsorption pattern. Evaluation of the dissolution behaviour of D-arabinose-loaded gelatin microparticles suggested that the saccharide, loaded at a level below the adsorption saturation level, was released uniformly over a 14-h period after the loaded gelatin microparticles had been lyophilized for a second time. When dissolution curves were corrected for the initial burst effect seen after the gelatin microparticles had been loaded at higher levels of D-arabinose and lyophilized, steady-state release rates were also evident over prolonged periods. In addition, it was evident that the D-arabinose was adsorbed onto internal surfaces of the hydrated gelatin matrix. Calculation of this internal surface demonstrated the influence of the concentration of the glutaraldehyde used as a cross-linking agent and this parameter, in turn, influenced both the adsorption maxima and the subsequent equilibrium release rates.

Application of this data base to a highly water-soluble complex polysaccharide antineoplastic agent, which has a higher molecular weight (22·4 kDa vs 150 Da), demonstrated similar behaviour in that a near zero-order release pattern over at least 16 h could be obtained by attention to the conditions under which the gelatin microparticles were made and subsequently loaded before lyophilization.
The Inhibitory Effect of Tannins on Lipid Peroxidation of Rat Heart Mitochondria
Authors: Hong Chuang-Ye , Wang Chein-Ping , Huang Shiang-Suo , Hsu Feng-Lin
Published: April 2011

We induced lipid peroxidation in rat heart mitochondria with ferrous sulphate (FeSO4)) and compared the inhibitory effect of various tannins on the peroxidation.

Oxygen consumption and malondialdehyde (MDA) formation were used to quantitate the amount of lipid peroxidation, and the free radical scavenger activity of tannins was measured with a diphenyl-ρ-picryl hydrazyl (DPPH) method.

Of 25 tannins and related compounds tested, catechin benzylthioether and procyanidin B-2 ben-zylthioether were the most potent in inhibiting lipid peroxidation, with inhibitory effects stronger than that of trolox, a water soluble analogue of vitamin E. The concentrations (IC50) required for catechin benzylthioether and procyanidin B-2 benzylthioether to inhibit oxygen consumption to 50% of control values were 0·85 and 2·0 μm, respectively, while their IC50 values from the inhibition of MDA formation were 0·9 and 1·70 μm, respectively. The IC50 values for catechin and procyanidin B-2 to inhibit oxygen consumption were 34·0 and 11·0 μm. Both compounds were less potent than their benzylthioether derivatives. However, the ability of catechin and procyanidin B-2 to scavenge DPPH were similar to that of their benzylthioether derivatives.

We conclude that conjugation with a benzylthioether group enhances the inhibitory effect of tannins on lipid peroxidation, and that the mechanism is not an increase in its scavenger activity.
Effect of Kil769, a Novel K+-channel Opener, on Sensitivity to Ca2+ of Contractile Elements and Inositol Phosphate Formation in Porcine Coronary Artery
Authors: Yokoyama Takashi , Kasai Hideo , Okada Yuji , Izumi Hideakira , Izawa Toshio , Ogawa Nobuyuki
Published: April 2011

To determine whether Kil769, a novel K+-channel opener, acts intracellularly in vasorelaxation, we compared the effects of Kil 769 on force of contraction, intracellular Ca2+ concentration ([Ca2+]i) and inositol phosphate (IP1) formation with those of Ca2+-channel blockers in isolated porcine coronary artery.

Kil 769 (10 μm) and verapamil (1 μm), which produced submaximal relaxation, reduced the increase in [Ca2+]i and force of contraction induced by 25 mM KC1. Verapamil reduced [Ca2+]i and the force of contraction to a similar extent but Kil 769 reduced force of contraction more strongly than it did [Ca2+]i. Kil 769 also inhibited U46619 (9,11-dideoxy-9α, 11α-methano-epoxy-PGF2a)-induced IP1 formation and glibenclamide blocked its inhibitory effect.

These results suggest that the opening of K+ channels induced by Kil 769 reduces the Ca2+ sensitivity of contractile elements and inositol phospholipid hydrolysis which is related to the Ca2+ release from intracellular storage.
Regulation of Immune Complexes Binding of Macrophages by Pectic Polysaccharide from Bupleurum falcatum L.: Pharmacological Evidence for the Requirement of Intracellular Calcium/Calmodulin on Fc Receptor Up-regulation by Bupleuran 2IIb
Authors: Matsumoto Tsukasa , Yamada Haruki
Published: April 2011

The pectic polysaccharide, bupleuran 2IIb, up-regulates Fc-receptor (FcR) expression on peritoneal macrophages in a dose-dependent manner. The intracellular signal transduction by bupleuran 2IIb leading to the expression of FcR was studied.

Neither the protein kinase C (PKC) inhibitor, 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine dihydrochloride, nor the structurally distinct PKC antagonist, calphostin C, inhibited bupleuran 2IIb-induced up-regulation of FcR, whereas two direct activators of PKC, L-α-l-oleoyl-2-acetyl-sn-3-glycerol and N-(6-phenylhexyl)-5-chloro-l-naphthalenesulphonamide were unable to up-regulate the expression of FcR. The protein kinase A (PKA) inhibitor, N-[2-(methylamino)ethyl]-5-isoquinolinesulphonamide dihydrochloride also did not inhibit bupleuran 2IIb-induced up-regulation of FcR. Fluorescence image analysis using the calcium-sensitive dye, Fura-2, demonstrated that bupleuran 2IIb induced a rapid increase in intracellular levels of calcium (Ca2+). When macrophages were treated with calcium antagonist, 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride, bupleuran 2IIb-induced up-regulation of FcR was inhibited in a dose-dependent manner. The bupleuran 2IIb-induced up-regulation of FcR was also blocked by two structurally distinct calmodulin antagonists, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide hydrochloride. Furthermore, elevation of intracellular Ca2+ using the calcium ionophore, A23187, led to up-regulation of the FcR expression in a dose-dependent manner.

These results suggest that bupleuran 2IIb induces the up-regulation of FcR on macrophages by a mechanism dependent on an increase in intracellular Ca2+ followed by activation of the calmodulin, but not by a PKC or PKA pathway.
Antagonism by SB 204070 of 5-HT-evoked Contractions in the Dog Stomach: an In-vivo Model of 5-HT4 Receptor Function
Authors: Bingham S , King B F , Rushant B , Smith M I , Gaster L , Sanger G J
Published: April 2011

The ability of 5-hydroxytryptamine (5-HT) to evoke contractile activity in the gastric Heidenhain pouch was measured in conscious dogs using a method in which 5-HT4 receptor-antagonist activity can be measured in-vivo.

At doses of 5-HT which evoked short-lived measurable responses (5 or 10 μg kg−1, i.v.), it was found that this activity was greatly reduced by atropine (100 μg kg−1, i.v.), but was unaffected by methysergide, methiothepin, ketanserin (each at 100 μg kg−1, i.v.) or granisetron (10 or 100 μg kg−1, i.v.). At best SDZ 205–557 2-diethylaminoethyl-[2-methoxy-4-amino-5-chloro] benzoate; 100 μg kg−1, i.v.) reduced the action of 5-HT in 4/5 animals and increased it in the other but its effects were variable in magnitude and not consistently maintained. However, the more potent and selective 5-HT4-receptor antagonist SB 204070 (1-butyl-4-piperidinylmethyl 8-amino-7-chloro-1,4-benzodioxan-5-carboxylate hydrochloride) dose-dependently antagonized the 5-HT-evoked contractions in all dogs tested. This action was reversible, but long-lasting with an effective half-life of 18·0 h when administered at 1 μg kg−1. The estimated ID50 value was 0·55 μg kg−1.
Femoral Vasodilation to Cromakalim is Blocked by U37883A, a Non-sulphonylurea that Selectively Inhibits KATP Channels
Authors: Lippton Howard , Choe Ella , Franklin Ernest , Grivas Tania , Flint Lewis , Hyman Albert , Ferrara John
Published: April 2011

The purpose of the present study was to determine the effects of U37883A, a non-sulphonylurea inhibitor of KATP channels, in the femoral vascular bed of the anaesthetized dog.

Administration of U37883A, 4-morpholinecarboxamidine-N-1-adamentyl-N-cyclohexyl hydrochloride (2·5 mg kg−1, i.v.), significantly inhibited the femoral vasodilator response to intra-femoral arterial injection of cromakalim, an activator of KATP channels. In contrast, U37883A had no effect on the femoral vasodilator responses to nitroglycerin, isoprenaline, 5-HT, or 5-carboxamidotryptamine, suggesting this agent is a novel and selective inhibitor of hindlimb vasodilation induced by KATP-channel activation.

Since U37883A did not significantly alter baseline femoral blood flow and femoral vascular resistance, the present data suggest that KATP channels do not contribute, in large measure, to regulating the canine femoral vascular bed under resting conditions in-vivo.
Defibrotide Protects Endothelial Cells, but not L929 Tumour Cells, from Tumour Necrosis Factor-α-mediated Cytotoxicity
Authors: Schröder Henning
Published: April 2011

The effect of defibrotide on the cytotoxicity of tumour necrosis factor-α was investigated in cultured bovine pulmonary artery endothelial cells and L929 mouse tumour cells.

In endothelial cells, a 72-h incubation with tumour necrosis factor-α (1 and 10 ng mL−1) reduced the number of viable cells to 63 and 51% of control, respectively. Simultaneous incubation with defibrotide (0·03-0·3 mg mL−1) protected endothelial cells from tumour necrosis factor-α-mediated cytotoxicity, and increased viability in a concentration-dependent fashion to 98% of control at 1 ng mL−1 tumour necrosis factor-α and to 80% of control at 10 ng mL−1 tumour necrosis factor-α. However, under the same conditions a similar cytotoxic response to tumour necrosis factor-α in L929 tumour cells remained unaltered in the presence of defibrotide.

These findings demonstrate protection from tumour necrosis factor-α-mediated toxicity by defibrotide in endothelial cells but not in a tumour cell line. It is concluded that defibrotide might serve as a therapeutic agent to limit the vascular toxicity of tumour necrosis factor-α without affecting its antineoplastic activity.
Differential Effects of Dopamine Antagonists on Evoked Dopamine Release from Slices of Striatum and Nucleus Accumbens in Rats
Authors: Yamada Shigeto , Takaki Toshihiro , Yokoo Hideyasu , Tanaka Masatoshi
Published: April 2011

The effects of dopamine-receptor antagonists on electrically-evoked dopamine release were compared in the nucleus accumbens and striatal slices of rats.

(-)-Sulpiride induced a concentration-dependent increase in the evoked dopamine release from both regions, the increase in the nucleus accumbens being significantly greater than that in the striatum. Clozapine also increased evoked dopamine release from the nucleus accumbens, but not from the striatum. The haloperidol-induced increase in evoked dopamine release from the nucleus accumbens was less than that from the striatum.

These findings indicate that, in terms of dopamine transmission, (-)-sulpiride and clozapine, but not haloperidol, predominantly affect the nucleus accumbens rather than the striatum. We have previously reported that the contribution of D3 receptors to the regulation of dopamine release from dopamine nerve terminals is much greater in the nucleus accumbens than that in the striatum. (-)-Sulpiride and clozapine have relatively higher affinity for D3 receptors than does haloperidol. The regional differences in responsiveness of dopamine release to dopamine antagonists could be due to the different affinities to D2 or D3 receptors of the dopamine antagonists.
In-vivo Activity of Retinoid Esters in Skin is Related to In-vitro Hydrolysis Rate
Authors: Chen Simon , Darling Inger M , Yu Kuo-Long , Starrett John E , Mansuri Muzammil M , Whiting Gary , Tramposch Kenneth M
Published: April 2011

BMS-181163 (4-acetamidophenyl retinoate, previously reported as BMY-30123), the acetamidophenyl ester of all-trans-retinoic acid (tRA), is topically active in various retinoid-sensitive animal models, but was recently shown to be ineffective for the treatment of acne in patients. To determine whether BMS-181163 functions as a prodrug of tRA in mice but not in man, the relative rates of ester hydrolysis in mouse and human skin homogenates were determined.

In-vitro hydrolysis assays showed that BMS-181163 was substantially hydrolysed in mouse skin homogenates and minimally in human skin preparations. In addition, a series of phenyl esters of tRA and several known active synthetic retinoids (Ch-80: (E)-4-[3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl] benzoic acid; CD-271: 6-[3-(1-adamantyl)-4-methyoxyphenyl]-2-naphthoic acid; and TTNPB: (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl] benzoic acid) was prepared and hydrolysis rates and in-vivo (rhino mouse utriculi reduction) activities were compared. The hydrolysis rates of the six test retinoid phenyl esters, ranging from 0·06 to 2·0 h−1 were found to correlate with the in-vivo activity. Those esters (BMS-181163 and acetamidophenyl esters of Ch-80 and TTNPB) with a higher hydrolysis rate exhibited in-vivo activity only slightly lower than their parent free acid retinoids. In contrast, the three phenyl esters with a hydrolysis rate less than 0·3 h−1 were inactive in-vivo.

Data from both approaches suggest that the breakdown of the phenyl ester linkage in this series is essential for the respective in-vivo activity and that the active phenyl esters of retinoids function as prodrugs.
Disposition of Polaprezinc (Zinc l-Carnosine Complex) in Rat Gastrointestinal Tract and Effect of Cimetidine on its Adhesion to Gastric Tissues
Authors: Furuta Shigeru , Toyama Seiji , Miwa Masahiro , Sano Hiroshi
Published: April 2011

The disposition of polaprezinc in the rat gastrointestinal tract was studied by a double tracer method using [14C]- and [65Zn]polaprezinc. At 0·5 h after oral administration of [14C]-, [65Zn]polaprezinc to rats, the 14C-radioactivity in the gastric contents was comparable with the 65Zn-radioactivity. However, a significant difference was observed in the time course of changes in gastric contents between 14C- and 65Zn-radioactivity over 1 h after administration, indicating that polaprezinc existed in complex form at 0·5 h after administration and was dissociated to l-carnosine and zinc in the gastrointestinal tract as a function of time.

The adhesion of zinc to stomach mucosa after oral administration of polaprezinc to rats was significantly increased by treatment with cimetidine.

These results suggest that the adhesion of zinc to gastric tissues is increased by inhibiting the dissociation of polaprezinc, and that H2-receptor antagonists, such as cimetidine, may increase anti-ulcer effects of polaprezinc.