bluuebunny/crossref_metadata_2025_split huggingface dataset:
A pharmacological study of NK1 and NK2 tachykinin receptor characteristics in the rat isolated urinary bladder
Authors: Hall Judith M. , Flowers Joanna M. , Morton Ian K.M. 
Published: July 2012

We have estimated potencies of tachykinin receptor agonist and antagonist analogues in order to determine the recognition characteristics of tachykinin receptors mediating phasic contractile responses of the rat isolated urinary bladder in vitro.
The NK1‐selective synthetic agonists, substance P methyl ester and GR73632, the synthetic NK2‐selective agonists [β‐Ala8]‐NKA(4–10) and GR64349, and the mammalian tachykinins, neurokinin A and neurokinin B, were assayed relative to substance P and were found to be approximately equipotent. The NK3‐selective agonist, senktide, was inactive (10 μm).
Potencies of all these agonists were not significantly different (P > 0.05) when experiments were carried out in the presence of the neutral endopeptidase inhibitor, phosphoramidon, and the kininase II inhibitor, enalaprilat (both 1 μm).
The NK1‐selective antagonist, GR82334, inhibited responses to substance P methyl ester in a competitive manner in the rat urinary bladder and the rat ileum, and also in the guinea‐pig ileum. Markedly different pKB estimates were obtained in the rat bladder (6.38) and rat ileum (6.56) compared to the guinea‐pig ileum (7.42). GR82334 (3 μm) was inactive against responses of the rat bladder to [β‐Ala8]‐NKA(4–10).
The NK1‐selective antagonist (±)‐CP‐96,345 also inhibited responses of the rat bladder and guinea‐pig ileum to substance P methyl ester; however, in the rat bladder at 1 μm, this antagonist reversibly inhibited responses both to the NK2‐selective agonist [β‐Ala8]‐NKA(4–10) and to the muscarinic agonist carbachol (P ≤ 0.01), thus showing evidence of some non‐selective depressant actions.
The NK2‐selective antagonists, MEN10207 and L‐659,874, competitively inhibited responses of the rat bladder to the NK2‐selective agonist [β‐Ala8]‐NKA(4–10) giving pKB estimates of 5.75 and 6.68, respectively. Both antagonists (10 μm) were inactive against responses to the NK1‐selective agonist substance P methyl ester.
These results support the proposal of a mixed population of NK1 and NK2 receptors mediating contraction of the rat isolated urinary bladder. The NK2 receptor is characterized by a relatively low affinity for the NK2‐selective antagonist MEN10207 but a high affinity for L‐659,874. The NK1‐mediated responses are inhibited by (±)‐CP‐96,345: this compound however, has non‐specific depressant effects in the rat bladder at high concentration (1 μm). In contrast, the NK1‐receptor peptide antagonist GR82334, did not have non‐specific depressant effects and competitively inhibited NK1 responses in the rat bladder and rat ileum with an affinity significantly lower than at the NK1‐receptors in the guinea‐pig ileum.
Pharmacological profile of a high affinity dipeptide NK1 receptor antagonist, FK888
Authors: Fujii Takashi , Murai Masako , Morimoto Hiroshi , Maeda Yasue , Yamaoka Makiko , Hagiwara Daijiro , Miyake Hiroshi , Ikari Norihiro , Matsuo Masaaki 
Published: July 2012

In our search for compounds that inhibit the binding of [3H]‐substance P (SP) to guinea‐pig lung membranes, the dipeptide SP antagonist, FK888, was developed by chemical modification of the parent compound, (d‐Pro4, d‐Trp7,9,10, Phe11)SP4– 11.
In a [3H]‐SP binding assay using guinea‐pig lung membranes and rat brain cortical synaptic membranes, FK888 displaced [3H]‐SP binding with a Ki value of 0.69 ± 0.13 nm and 0.45 ± 0.17 μm, respectively, in a competitive manner.
FK888 inhibited the contraction of guinea‐pig isolated ileum induced by SP in the presence of atropine and indomethacin (a NK1 receptor bioassay) with a pA2 value of 9.29 (8.60–9.98).
FK888 inhibited contractions of rat vas deferens by NKA (a NK2 receptor bioassay) and of rat portal vein by NKB (a NK3 receptor bioassay) at concentrations at least 10,000 times greater than that required to inhibit contractions of guinea‐pig ileum.
FK888 also inhibited SP‐induced airway oedema in guinea‐pig after both intravenous and oral administration.
These data demonstrate that FK888 is a potent and selective NK1 antagonist which is active both in vitro and in vivo.
Membrane potential and current responses to neurotensin in the longitudinal muscle of the rectum of the fowl
Authors: Komori Seiichi , Matsuoka Takaaki , Kwon Seong‐Chun , Takewaki Tadashi , Ohashi Hidenori 
Published: July 2012

The effects of neurotensin (NT) on membrane potential and membrane current of the longitudinal smooth muscle of chicken rectum were investigated by intracellular recording and whole‐cell voltage clamp.
NT (3 nm−1.2 μm), when applied via the bathing medium, produced a concentration‐dependent membrane depolarization with an EC50 of 18 ± 2 nm (n = 7) which was accompanied by an increase in the membrane conductance. The effect was biphasic: an initial, rapid depolarization reached a peak within 2–3 min and then declined to a lower but still elevated level which was sustained until washout.
Excitatory junction potentials (e.j.ps), which were non‐adrenergic non‐cholinergic (NANC) in nature, were decreased in amplitude and total duration in the presence of NT (0.6 μm). The depression of the e.j.p. was due mainly to the reduction of the membrane resistance.
When NT was applied locally by means of pressure ejection from a micropipette containing NT, some cells responded with a membrane depolarization and some failed to respond, whereas e.j.ps could invariably be elicited from all of them.
In single muscle cells enzymatically isolated from the muscle and dialyzed under voltage clamp at — 50 mV with a CsCl‐rich solution, NT (5 or 10 μm) produced an inward current. NT‐induced inward currents were obtained with inclusion of 10 mm EGTA in the pipette solution and their reversal potential was around 0 mV. In cells dialyzed under voltage clamp at 0 mV with a KCl‐rich solution, NT (5 μm) produced a brief outward current followed by abolition of spontaneous transient outward currents.
The present results suggest that the membrane depolarization, which may arise from activation of non‐selective cation channels, and release of calcium from internal stores produced by neurotensin are responsible for its contractile activity in the longitudinal smooth muscle of chicken rectum. Further, the depolarizing effect may provide support for the involvement of NT in the NANC transmission in this preparation.
Antagonism of kinin effects on epithelia by Hoe 140: apparently competitive and non‐competitive interactions
Authors: Cuthbert A.W. , MacVinish L.J. , Pickles R.J. 
Published: July 2012

Hoe‐140, a potent kinin receptor antagonist, was investigated for its ability to inhibit the effects of lysylbradykinin (kallidin) on a cultured colonic epithelium, HCA‐7 Colony 29, derived from a human adenocarcinoma.
Measurements of electrogenic chloride secretion (as short circuit current), and of intracellular Ca2+ (from Fura‐2 fluorescence) were used to assess the action of lysylbradykinin in the absence and presence of Hoe 140.
From short circuit current data, Hoe 140 appeared to be a competitive antagonist with a Ki value of 5 nm. However, with measurements of intracellular Ca2+ Hoe 140 was apparently a non‐competitive antagonist with a Ki of between 4–6 nm.
Because of the unexpected finding of non‐competitive antagonism, measurements were made with a second antagonist pair, histamine and mepyramine. Mepyramine behaved as a competitive antagonist against responses to histamine with a Ki value of ≅5 nm when short circuit current measurements were evaluated. However, when intracellular Ca2+ concentration was used as a measure mepyramine, 30 nm, produced a near parallel shift in the response curve, but at 100 nm the maximal response was depressed.
The reasons why the apparent type of antagonism depends upon the method of measurement is discussed, bearing in mind that the increase in intracellular Ca2+ is a signal which precedes the increase in short circuit current.
Angiotensin converting enzyme binding sites in human heart and lung: comparison with rat tissues
Authors: Vago T. , Bevilacqua M. , Conci F. , Baldi G. , Ongini E. , Chebat E. , Monopoli A. , Norbiato G. 
Published: July 2012

Angiotensin converting enzyme (ACE), a dipeptidyl carboxypeptidase which catalyzes the final activation step in the formation of angiotensin II, was identified by radioligand studies in rat heart and lung. In this work we identified ACE binding sites in human left ventricle and lung by radioligand binding using the ACE inhibitor [3H]‐ramiprilat, and compared its binding characteristics in human and rat tissues.
Binding of [3H]‐ramiprilat in all tissues tested was saturable, temperature and zinc‐dependent, and inhibited by EDTA. In human left ventricle homogenate we found a density of binding sites of 121 ± 15 fmol mg−1 protein (n = 4) with an affinity (Kd) of 850 ± 55 pm, whereas in rat left ventricle the same values were 23 ±4 fmol mg−1 protein and 315 ± 30 pm, (n = 4), respectively.
[3H]‐ramiprilat binding to rat (n = 4) and human lung (n = 4) showed a binding site density of 2132 ± 155 and 1085 ± 51 fmol mg−1 protein respectively with an affinity of 639 ± 54 and 325 ± 22 pm. The lung: heart ratio of ACE binding site density was about 9:1 in man and 100:1 in rat.
The binding affinities of 13 ACE inhibitors were evaluated on human heart and lung: the drugs tested showed a wide range of affinities for the ACE binding sites in both tissues, and the affinity for lung was significantly greater than for heart for most of the drugs.
The greater potency of some ACE inhibitors in displacing [3H]‐ramiprilat in human lung compared with the heart indicates differences between ACE binding sites in these tissues and suggests the possibility of a selective organ‐targeted therapeutic approach.
Endotoxin impairs the response of rabbit mesenteric artery to electrical stimulation via a prejunctional mechanism
Authors: Tomikawa Shigeji , Okabe Eiichiro 
Published: July 2012

The effect of E. coli lipopolysaccharide (LPS) on sympathetic neuro‐effector transmission was studied in the rabbit mesenteric artery. The experiments were performed on artery rings isolated 5 or 20 h after intravenous treatment with LPS or saline as well as on artery rings isolated from non‐treated rabbits (for assessment of the effect of in vitro preincubation with LPS). In most experiments, neural elements in the arteries were stimulated electrically (10 V, 2 ms, 1–32 Hz).
Preincubation with LPS (10 μg ml−1) for 5 or 20 h had no effect on the contraction responses of endothelium‐intact artery rings to electrical stimulation. In contrast, in vivo intravenous pretreatment with LPS (10 μg) led to an inhibition of the contraction; LPS elicited this effect when injected 20 h, but not 5 h, before the experiment. The effect of LPS was eliminated in artery rings isolated from animals receiving an inhibitor of protein synthesis (actinomycin D or cycloheximide) before treatment with LPS. LPS (injected 20 h before the experiment) had no effect on the concentration‐response curves for exogenous noradrenaline and tyramine in endothelium‐intact artery rings.
The inhibition of electrically induced contractions produced by LPS treatment in endothelium‐intact artery rings was attenuated by atropine and yohimbine, but not by phentolamine. Yohimbine plus atropine restored the depressed contraction to the normal level. Clonidine and acetylcholine mimicked the effect of LPS in endothelium‐intact artery rings isolated from saline‐treated animals.
When steady‐state contractions were induced by 5 min of stimulation at 16 Hz, acetylcholine or clonidine reduced the contraction in endothelium‐denuded artery rings from both saline‐treated rabbits and animals receiving LPS 20 h before the experiment. The reduction produced by acetylcholine or clonidine of the contraction in artery rings from LPS‐treated rabbits was significantly greater than in artery rings from saline‐treated animals.
These results suggest that treatment of rabbits with LPS inhibits noradrenaline release from sympathetic nerve endings via increased sensitivity of both prejunctional inhibitory muscarinic receptors and α2‐adrenoceptors in mesenteric arteries. They also suggest that the effect of LPS is independent of endothelial cells but linked to protein synthesis.
Nitric oxide synthase in ferret brain: localization and characterization
Authors: Matsumoto Takahiro , Mitchell Jane A. , Schmidt Harald H.H.W. , Kohlhaas Kathy L. , Warner Timothy D. , Förstermann Ulrich , Murad Ferid 
Published: July 2012

In the present study, we have investigated the distribution of nitric oxide synthase in the ferret brain. Nitric oxide snythase was determined biochemically and immunochemically.
In the rat brain, the highest nitric oxide snythase activity has been detected in the cerebellum. However, in the ferret brain, the highest activity was found in the striatum and the lowest in the cerebellum and cerebral cortex. The enzymatic activity was localized predominantly in the cytosolic fractions, it was dependent on NADPH and Ca2+, and inhibited by NG‐nitro‐l‐arginine or NG‐methyl‐l‐arginine.
Western blot analysis revealed that all regions of the ferret brain contained a 160 kD protein crossreacting with an antibody to nitric oxide synthase purified from the rat cerebellum, and the levels of relative intensity of staining by the antibody correlated with the distribution of nitric oxide synthase activity.
These results indicate that the ferret brain contains a nitric oxide snythase similar to the rat brain, but the distribution of enzymatic activity in the ferret brain differs markedly from the rat brain.
Endothelin ETA and ETB receptors mediate vascular smooth muscle contraction
Authors: Sumner Michael J. , Cannon Toby R. , Mundin Jason W. , White David G. , Watts Ian S. 
Published: July 2012

We have investigated the receptors mediating endothelin‐induced contraction of rabbit isolated jugular vein (RJV) and rat isolated thoracic aorta (RTA).
Endothelin‐1 (ET‐1) and endothelin‐3 (ET‐3) contracted RJV preparations with similar potency (EC50 values ∼ 1 nm), whereas, ET‐1 (EC50:4.5 nm) was ∼ 80 fold more potent than ET‐3 in contracting RTA. In addition, the ETB receptor‐selective agonist [Ala1,3,11,15]ET‐l contracted RJV (EC50:2.1 nm) but not RTA.
The ETA receptor antagonist, BQ123, competitively antagonized (pA2 6.93) the contraction of RTA produced by ET‐1, but had no effect (at 10 μm) on the contractile effects of either ET‐1, ET‐3 or [Ala1,3,11,15]ET‐1 in RJV.
These data suggest that both ETA and ETB receptors can mediate vascular smooth muscle contraction.
Protection against the effects of anticholinesterases on the latencies of action potentials in mouse skeletal muscles
Authors: Kelly S.S. , Ferry C.B. , Bamforth J.P. , Das S.K. 
Published: July 2012

Adult male albino mice were injected subcutaneously with an organophosphorous anticholinesterase to initiate excessive variability in the latency of indirectly elicited muscle action potentials (jitter) when assessed 5 days later.
Pretreatment of the mice with a single dose of pyridostigmine prevented the development of jitter after subsequent dosing with an organophosphate.
Treatment with one dose of pralidoxime (2PAM) prevented the development of jitter if given less than 1 h after treatment with ecothiopate, a reactivatable inhibitor of cholinesterase. Similar treatment with 2PAM after a non‐reactivatable inhibitor did not prevent the development of jitter. The repeated administration of 2PAM over 12 h did ameliorate jitter.
Pretreatment of mice orally with α‐tocopherol and N‐acetylcysteine, known to prevent ecothiopateinduced myopathy, did not prevent the development of jitter after ecothiopate.
It is concluded that the development of jitter was a consequence of the inhibition of acetylcholinesterase, and although jitter did not develop acutely, the potential for the full development of jitter was achieved about 1 h after intoxication with ecothiopate. The development of jitter did not involve the generation of free radicals. Reduction of the early effects of intoxication with anticholinesterases by pyridostigmine or 2PAM prevented the development of jitter.
Ornithine and histidine decarboxylase activities in mice sensitized to endotoxin, interleukin‐1 or tumour necrosis factor by d‐galactosamine
Authors: Endo Yasuo , Kikuchi Takashi , Nakamura Masanori 
Published: July 2012

An injection of d‐galactosamine (GalN) into mice together with a lipopolysaccharide (LPS or endotoxin), interleukin‐1 (IL‐1) or tumour necrosis factor (TNF), sensitized the mice and induced fulminant hepatitis with severe congestion resulting in rapid death. Since LPS and these cytokines induce ornithine decarboxylase (ODC) and histidine decarboxylase (HDC) in the liver and spleen of mice, the effects of GalN on the induction of ODC and HDC in these organs were examined.
The induction of ODC by LPS, IL‐1 or TNF was suppressed by GalN in the liver, and this suppression preceded the hepatic congestion. There was good agreement between the degree of hepatic congestion and the suppression of ODC induction by various amounts of GalN. The induction of ODC in the spleen was suppressed only at the highest dose of GalN examined.
GalN is known to deplete uridine 5′‐triphosphate (UTP), resulting in the suppression of RNA and protein synthesis. An injection of uridine, the precursor of UTP, diminished the GalN‐induced suppression of ODC induction by LPS and prevented the hepatic congestion and death.
LPS‐pretreatment before injection of LPS plus GalN prevented the suppression of ODC activity and prevented the hepatic congestion and death.
An injection of putrescine, the product of ODC, prolonged survival time and delayed the development of hepatic congestion. However, injection of an ODC inhibitor into the mice given LPS did not produce hepatic congestion.
The induction of HDC in the liver by LPS, IL‐1 or TNF was not suppressed by GalN and, at high doses, the response to LPS was enhanced. An inhibitor of HDC neither prevented the hepatic congestion nor enhanced the protective effect of putrescine.
Although GalN in combination with IL‐1α induced a markedly higher HDC activity than was observed when it was combined with TNFα, and suppressed the induction of ODC, the former combination at the doses used did not produce hepatic congestion or death. However, the sensitization to TNFα by GalN was markedly potentiated by IL‐1α.
These results suggest that suppression of the induction of ODC by GalN may be one cause of the sensitization to LPS, IL‐1 or TNF, and that the induction of HDC, i.e. histamine formation, may not be involved in this sensitization.
These results are consistent with the hypothesis that both IL‐1 and TNF are involved in the sensitization to LPS.
Regulation of apoptosis in HL‐1 cardiomyocytes by phosphorylation of the receptor tyrosine kinase EphA2 and protection by lithocholic acid
Authors: Jehle J , Staudacher I , Wiedmann F , Schweizer PA , Becker R , Katus HA , Thomas D 
Published: July 2012

Background and PurposeHeart failure and atrial fibrillation are associated with apoptosis of cardiomyocytes, suggesting common abnormalities in pro‐apoptotic cardiac molecules. Activation of the receptor tyrosine kinase EphA2 causes apoptosis in vitro, and dysregulation of EphA2‐dependent signalling is implicated in LEOPARD and Noonan syndromes associated with cardiomyopathy. Molecular pathways and regulation of EphA2 signalling in the heart are poorly understood. Here we elucidated the pathways of EphA2‐dependent apoptosis and evaluated a therapeutic strategy to prevent EphA2 activation and cardiac cell death.Experimental ApproachEphA2 signalling was studied in an established model of doxazosin‐induced apoptosis in HL‐1 cells. Apoptosis was measured with TUNEL assays and as cell viability using a formazan method. Western blotting and siRNA for EphA2 were also used.Key ResultsApoptosis induced by doxazosin (EC50 = 17.3 μM) was associated with EphA2 activation through enhanced phosphorylation (2.2‐fold). Activation of pro‐apoptotic downstream factors, phospho‐SHP‐2 (3.9‐fold), phospho‐p38 MAPK (2.3‐fold) and GADD153 (1.6‐fold) resulted in cleavage of caspase 3. Furthermore, two anti‐apoptotic enzymes were suppressed (focal adhesion kinase, by 41%; phospho‐Akt, by 78%). Inactivation of EphA2 with appropriate siRNA mimicked pro‐apoptotic effects of doxazosin. Finally, administration of lithocholic acid (LCA) protected against apoptosis by increasing EphA2 protein levels and decreasing EphA2 phosphorylation.Conclusions and ImplicationsEphA2 phosphorylation and activation of SHP‐2 are critical steps in apoptosis. Reduction of EphA2 phosphorylation by LCA may represent a novel approach for future anti‐apoptotic treatment of heart failure and atrial fibrillation.
Substance Use Patterns among High‐Risk American Indians/Alaska Natives in Los Angeles County
Authors: Dickerson Daniel L. , Fisher Dennis G. , Reynolds Grace L. , Baig Safia , Napper Lucy E. , Anglin M. Douglas 
Published: July 2012

Background:
Substance abuse among American Indians/Alaska Natives (AI/ANs) is a significant and long‐standing health problem in the U.S. Two‐thirds of American AIs/ANs reside in the urban setting. However, studies analyzing substance use characteristics among urban AI/ANs are very limited.
Methods:Substance use patterns among a sample of AI/ANs (n = 77) and other ethnic/racial groups in Los Angeles County at high risk of substance abuse were analyzed utilizing three datasets from programs targeting individuals at high risk for substance abuse and risky sexual behaviors.  Results:Compared to all other ethnic/racial groups, AI/ANs demonstrated significantly younger age of onset of alcohol, marijuana, methamphetamine, and “other” drug use, higher correlations of age of first use of amphetamine with a measure of the drug's reinforcement, and higher mean number of illicit drug injections in the 30 days before being interviewed.  Conclusions:Results from this study highlight a critical need for furthering our understanding of substance abuse problems among urban AI/ANs.(Am J Addict 2012;00:1–8)