bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen‐derived free radicals mediate endothelium‐dependent contractions to acetylcholine in aortas from spontaneously hypertensive rats
Authors: Yang Di , Félétou Michel , Boulanger Chantal M. , Wu Heng‐Fang , Levens Nigel , Zhang Ji‐Nan , Vanhoutte Paul M. 
Published: January 2005

Experiments were designed to investigate whether or not oxygen‐derived free radicals mediate endothelium‐dependent contractions to acetylcholine in the aorta of spontaneously hypertensive rat (SHR).
Isometric tension was measured in aortic rings taken from adult male SHR and Wistar‐Kyoto rat (WKY) in the presence of NG‐nitro‐L‐arginine.
Endothelium‐dependent contractions to acetylcholine were significantly greater in rings from SHR compared to WKY. Oxygen‐derived free radicals, generated from xanthine plus xanthine oxidase, induced contractions that were larger in aortas from SHR than from WKY. Contractions to acetylcholine and free radicals were abolished by a selective TP‐receptor antagonist, S 18886, and a preferential inhibitor of cyclo‐oxygenase‐1, valeryl salicylate, but not by a preferential inhibitor of cyclo‐oxygenase‐2, NS‐398.
Allopurinol, deferoxamine and the combination of superoxide dismutase plus catalase inhibited the contractions to oxygen‐derived free radicals but did not significantly affect those to acetylcholine. In contrast, diethyldithiocarbamic acid, an inhibitor of superoxide dismutase, or Tiron, a scavenger of superoxide anion, reduced endothelium‐dependent contractions to acetylcholine in aortas from SHR. The effect of these two drugs was additive.
In SHR chronically treated with dimethylthiourea endothelium‐dependent contractions to acetylcholine were decreased, and reduced further by acute in vitro exposure to deferoxamine or the combination of superoxide dismutase plus catalase.
These results suggest that in the SHR aorta acetylcholine‐induced endothelium‐dependent contractions involve endothelial superoxide anion production and the subsequent dismutation into hydroxyl radicals and/or hydrogen peroxide. The free radicals activate cyclo‐oxygenase‐1, most likely to produce endoperoxides. Activation of TP‐receptors is required to observe endothelium‐dependent contractions to acetylcholine or endothelium‐independent contractions in response to free radical generation.

British Journal of Pharmacology (2002) 136, 104–110; doi:10.1038/sj.bjp.0704669
Relaxation by urocortin of human saphenous veins
Authors: Sanz Elena , Monge Luis , Fernández Nuria , Martínez María Angeles , Martínez‐León Juan B. , Diéguez Godofredo , García‐Villalón Angel Luis 
Published: January 2005

Urocortin, an endogenous peptide structurally related to corticotropin‐releasing factor (CRF), has potent cardiovascular effects, suggesting that it may be of significance in cardiovascular regulation. The objective of this study was to analyse the effects of urocortin and its action mechanisms on human blood vessels.
To this, 3 mm long segments from human saphenous veins were prepared for isometric tension recording in an organ bath.
In the segments at basal resting tone, urocortin did not produce any effect, but in the segments precontracted with endothelin‐1 (1 – 10 nM), urocortin (1 pM – 10 nM) produced concentration‐dependent relaxation.
This relaxation was not modified by the inhibitor of nitric oxide synthase NG‐nitro‐L‐arginine methyl ester (L‐NAME, 100 μM), but it was potentiated by the cyclo‐oxygenase inhibitor meclofenamate (10 μM) and it was reduced by the inhibitors of high‐conductance Ca2+‐dependent potassium channels tetraethylammonium (TEA, 10 mM) and charybdotoxin (100 nM).
These results indicate that human saphenous veins are very sensitive to urocortin, which produces vascular relaxation by a mechanism independent of nitric oxide and dependent of high‐conductance Ca2+‐dependent potassium channels, and that it may be opposed by the release of vasoconstrictor prostanoids. Therefore, urocortin may be of significance for regulation of the venous circulation in humans.

British Journal of Pharmacology (2002) 136, 90–94; doi:10.1038/sj.bjp.0704670
Thioridazine interacts with the membrane of mitochondria acquiring antioxidant activity toward apoptosis – potentially implicated mechanisms
Authors: Rodrigues Tiago , Santos Antonio C. , Pigoso Acácio A. , Mingatto Fábio E. , Uyemura Sérgio A. , Curti Carlos 
Published: January 2005

We evaluated the effects of the phenothiazine derivative thioridazine on mechanisms of mitochondria potentially implicated in apoptosis, such as those involving reactive oxygen species (ROS) and cytochrome c release, as well as the involvement of drug interaction with mitochondrial membrane in these effects.
Within the 0 – 100 μM range thioridazine did not reduce the free radical 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) nor did it chelate iron.
However, at 10 μM thioridazine showed important antioxidant activity on mitochondria, characterized by inhibition of accumulation of mitochondria‐generated O2•−, assayed as lucigenin‐derived chemiluminescence, inhibition of Fe2+/citrate‐mediated lipid peroxidation of the mitochondrial membrane (LPO), assayed as malondialdehyde generation, and inhibition of Ca2+/t‐butyl hydroperoxide (t‐BOOH)‐induced mitochondrial permeability transition (MPT)/protein‐thiol oxidation, assayed as mitochondrial swelling.
Thioridazine respectively increased and decreased the fluorescence responses of mitochondria labelled with 1‐aniline‐8‐naphthalene sulfonate (ANS) and 1‐(4‐trimethylammonium phenyl)‐6 phenyl 1,3,5‐hexatriene (TMA‐DPH).
The inhibition of LPO and MPT onset correlated well with the inhibition of cytochrome c release from mitochondria.
We conclude that thioridazine interacts with the inner membrane of mitochondria, more likely close to its surface, acquiring antioxidant activity toward processes with potential implications in apoptosis such as O2•− accumulation, as well as LPO, MPT and associated release of cytochrome c.

British Journal of Pharmacology (2002) 136, 136–142; doi:10.1038/sj.bjp.0704672
2‐Chloro N6‐methyl‐(N)‐methanocarba‐2′‐deoxyadenosine‐3′,5′‐bisphosphate is a selective high affinity P2Y1 receptor antagonist
Authors: Boyer José L , Adams Mary , Ravi R Gnana , Jacobson Kenneth A , Harden T Kendall 
Published: January 2005

We reported previously that bisphosphate derivatives of adenosine are antagonists of the P2Y1 receptor and that modification of the ribose in these analogues is tolerated in the P2Y1 receptor binding pharmacophore.
Here we delineate the pharmacological activity of one such non‐nucleotide molecule, 2‐chloro N6‐methyl‐(N)‐methanocarba‐2′‐deoxyadenosine‐3′,5′‐bisphosphate (MRS2279), in which the ribose is replaced by a cyclopentane ring constrained in the (N)‐conformation by a cyclopropane moiety.
MRS2279 antagonized 2MeSADP‐stimulated inositol phosphate formation in turkey erythrocyte membranes with competitive kinetics (pKB=7.75). High affinity competitive antagonism by MRS2279 was also observed at the human P2Y1 receptor (pKB=8.10) stably expressed in 1321N1 human astrocytoma cells. Antagonism was specific for the P2Y1 receptor since MRS2279 had no effect on activation of the human P2Y2, P2Y4, P2Y6, or P2Y11 receptors by their cognate agonists.
MRS2279 also did not block the capacity of ADP to act through the Gi/adenylyl cyclase linked P2Y receptor of platelets to inhibit cyclic AMP accumulation.
In contrast, the P2Y1 receptor is known to be obligatory in the process of ADP‐induced platelet aggregation, and MRS2279 competitively inhibited ADP‐promoted platelet aggregation with an apparent affnity (pKB=8.05) similar to that observed at the human P2Y1 receptor heterologously expressed in 1321N1 cells.
Taken together these results illustrate selective high affinity antagonism of the P2Y1 receptor by a non‐nucleotide molecule that should prove useful for pharmacological delineation of this receptor in various tissues.

British Journal of Pharmacology (2002) 135, 2004–2010; doi:10.1038/sj.bjp.0704673
Regulation of human penile smooth muscle tone byprostanoid receptors
Authors: Angulo Javier , Cuevas Pedro , La Fuente Jose M. , Pomerol Jose M. , Ruiz‐Castañé Eduardo , Puigvert Ana , Gabancho Sonia , Fernández Argentina , Ney Peter , Sáenz de Tejada Iñigo 
Published: January 2005

We have characterized the prostanoid receptors involved in the regulation of human penile arterial and trabecular smooth muscle tone.
Arachidonic acid induced relaxation of human corpus cavernosum strips (HCCS) that was blocked by the cyclo‐oxygenase inhibitor, indomethacin, and augmented by the thromboxane receptor (TP) antagonist, SQ29548, suggesting that endogenous production of prostanoids regulates penile smooth muscle tone.
TP‐receptors mediate contraction of HCCS and penile resistance arteries (HPRA), since the agonist of these receptors, U46619, potently contracted HCCS (EC50 8.3±2.8 nM) and HPRA (EC50 6.2±2.2 nM), and the contractions produced by prostaglandin F2α at high concentrations (EC50 6460±3220 nM in HCCS and 8900±6700 nM in HPRA) were inhibited by the selective TP‐receptor antagonist, SQ29548 (0.02 μM).
EP‐receptors are responsible for prostanoid‐induced relaxant effects in HCCS because only prostaglandin E1 (PGE1), prostaglandin E2 and the EP2/EP4‐receptor agonist, butaprost, produced consistent relaxation of this tissue (EC50 93.8±31.5, 16.3±3.8 and 1820±1284 nM, respectively). In HPRA, both prostacyclin and PGE1 (EC50 60.1±18.4 and 109.0±30.9 nM, respectively) as well as the selective IP receptor agonist, cicaprost, and butaprost (EC50 25.2±15.2 and 7050±6020 nM, respectively) caused relaxation, suggesting co‐existence of IP‐ and EP‐receptors (EP2 and/or EP4).
In summary, endogenous production of prostanoids may regulate penile smooth muscle contractility by way of specific receptors. TP‐receptors mediate contraction in HCCS and HPRA, while the relaxant effects of prostanoids are mediated by EP2‐ and/or EP4‐receptors in HCCS and by EP‐ and IP‐receptors in HPRA.

British Journal of Pharmacology (2002) 136, 23–30; doi:10.1038/sj.bjp.0704675
Atorvastatin inhibition of cytokine‐inducible nitric oxide synthase expression in native endothelial cellsin situ
Authors: Wagner Andreas H. , Schwabe Oliver , Hecker Markus 
Published: January 2005

Animal experimental studies have demonstrated that inducible nitric oxide synthase (iNOS) expression correlates with neointima formation and is prevented by HMG‐CoA reductase inhibitors (statins). In the present study we have investigated the underlying mechanism of action of these drugs in isolated segments of the rat aorta.Western blot analysis and immunohistochemistry revealed that tumour necrosis factor α (TNFα) plus interferon‐γ (IFNγ) synergistically induce iNOS gene expression in the endothelium but not in the smooth muscle of these segments while constitutive endothelial NO synthase (eNOS) abundance was markedly reduced.Pre‐treatment with 1 – 10 μMatorvastatin, cerivastatin or pravastatin decreased TNFα plus IFNγ stimulated iNOS expression in the endothelium irrespective of the presence of the HMG‐CoA reductase product mevalonate (400 μM).Electrophoretic mobility shift assay experiments confirmed that the combination of TNFα plus IFNγ causes activation of the transcription factors STAT‐1 and NF‐κB in native endothelial cells. Neutralization of these transcription factors by employing the corresponding decoy oligonucleotides confirmed their involvement in TNFα plus IFNγ stimulated iNOS expression. Translocation of both transcription factors was attenuated by atorvastatin, and this effect was insensitive to exogenous mevalonate.The present findings thus demonstrate a specific HMG‐CoA reductase‐independent inhibitory effect of statins, namely atorvastatin, on cytokine‐stimulated transcription factor activation in native endothelial cellsin situand the subsequent expression of a gene product implicated in vascular inflammation. This effect may be therapeutically relevant and in addition provide an explanation for the reported rapid onset of action of these drugs in humans.British Journal of Pharmacology(2002)136, 143–149; doi:10.1038/sj.bjp.0704678
Involvement of purinergic signalling in central mechanisms of body temperature regulation in rats
Authors: Gourine Alexander V , Melenchuk Ekaterina V , Poputnikov Dmitry M , Gourine Valery N , Spyer K Michael 
Published: January 2005

P2 purinoreceptors are present in hypothalamic and brainstem nuclei that are involved in the regulation of body temperature (Tb). The role of ATP acting on these P2 receptors in thermoregulation was investigated by studying the effects of the stable ATP analogue α,β‐methyleneATP (α,β‐meATP) and P2 receptor antagonists suramin and pyridoxal‐5′‐phosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS) on Tb when injected intracerebroventricularly (i.c.v.) via a pre‐implanted cannula in conscious rats at various ambient temperatures and during lipopolysaccharide (LPS)‐induced fever.
Depending on ambient temperature, α,β‐meATP (0.2 μmol, i.c.v.) induced a fall in Tb (−3.3°C, P<0.05), no changes in Tb when compared to pre‐injection levels, or an increase in Tb (∼1.0°C, P<0.05) in rats maintained at 10°C, 25°C and 30°C ambient temperature, respectively.
Suramin (7 nmol, i.c.v.) induced a lasting (up to 6 h) increase in Tb (on average 1.2°C, P<0.05) in rats kept at 25°C or 30°C, but failed to induce any rise in Tb in rats at 10°C ambient temperature. An increase in Tb was also observed in rats (25°C ambient temperature) treated with PPADS (0.2 μmol, i.c.v.).
α,β‐meATP (0.2 μmol) injected i.c.v. or directly into the anterior hypothalamus caused a profound fall in Tb (by 0.9°C and 1.0°C, respectively; P<0.05) during LPS (E.coli; 50 μg kg−1)‐induced fever in rats at 25°C ambient temperature. Fever was initiated more rapidly in rats treated with suramin (7 nmol) or PPADS (70 nmol), however its late phase was unaffected. Suramin (7 nmol) and PPADS (70 nmol) injected at the time when fever was already developed (2.5 h after LPS injections) did not alter febrile Tb.
These data indicate that purinergic signalling may play a significant role in central mechanisms of Tb regulation at various ambient temperatures and during fever.

British Journal of Pharmacology (2002) 135, 2047–2055; doi:10.1038/sj.bjp.0704679
Identification of the monomeric G‐protein, Rhes, as an efaroxan‐regulated protein in the pancreatic β‐cell
Authors: Chan Sue L. F. , Monks Lara K. , Gao Hongwei , Deaville Pamela , Morgan Noel G. 
Published: January 2005

Efaroxan induces membrane depolarization by interaction with the pore forming subunit of the ATP‐sensitive potassium channel, Kir6.2. However, this effect is not responsible for its full secretory activity.
In this study we have used an anti‐idiotypic approach to generate antibodies that recognize additional proteins that may be regulated by efaroxan in pancreatic β‐cells.
Using these antisera in an expression cloning strategy we have identified a monomeric GTP‐binding protein, Rhes, as a potential target for regulation by imidazoline ligands. Rhes is shown to be expressed in β‐cells and its expression is regulated by efaroxan under conditions when a structurally related molecule, KU14R, is ineffective.
The results reveal that β‐cells express Rhes and suggest that changes in the expression of this molecule may regulate the sensitivity of β‐cells to imidazoline secretagogues.

British Journal of Pharmacology (2002) 136, 31–36; doi:10.1038/sj.bjp.0704680
The role of spinal neuropeptides and prostaglandins in opioid physical dependence
Authors: Trang Tuan , Sutak Maaja , Quirion Remi , Jhamandas Khem 
Published: January 2005

This study examined the role of spinal calcitonin gene‐related peptide (CGRP), substance P, and prostaglandins in the development and expression of opioid physical dependence.
Administration of escalating doses (5 – 100 mg kg−1, i.p.) of morphine for 7 days markedly elevated CGRP and substance P− immunoreactivity in the dorsal horn of the rat spinal cord. Naloxone (2 mg kg−1, i.p.) challenge decreased both CGRP and substance P immunoreactivity and precipitated a robust withdrawal syndrome.
Acute intrathecal pre‐treatment with a CGRP receptor antagonist, CGRP8 – 37 (4, 8 μg), a substance P receptor antagonist, SR 140333 (1.4, 2.8 μg), a cyclo‐oxygenase (COX) inhibitor, ketorolac (30, 45 μg), and COX‐2 selective inhibitors, DuP 697 (10, 30 μg) and nimesulide (30 μg), 30 min before naloxone challenge, partially attenuated the symptoms of morphine withdrawal. CGRP8 – 37 (8 μg), but no other agents, inhibited the decrease in CGRP immunoreactivity.
Chronic intrathecal treatment with CGRP8 – 37 (4, 8 μg), SR 140333 (1.4 μg), ketorolac (15, 30 μg), DuP 697 (10, 30 μg), and nimesulide (30 μg), delivered with daily morphine injection significantly attenuated both the symptoms of withdrawal and the decrease in CGRP but not substance P immunoreactivity.
The results of this study suggest that activation of CGRP and substance P receptors, at the spinal level, contributes to the induction and expression of opioid physical dependence and that this activity may be partially expressed through the intermediary actions of prostaglandins.

British Journal of Pharmacology (2002) 136, 37–48; doi:10.1038/sj.bjp.0704681
Effects of morphine and morphine withdrawal on brainstem neurons innervating hypothalamic nuclei that control thepituitary‐adrenocortical axis in rats
Authors: Laorden Maria Luisa , Castells Maria Teresa , Milanés Maria Victoria 
Published: January 2005

Different data support a role for brainstem noradrenergic inputs to the hypothalamic paraventricular nucleus (PVN) in the control of hypothalamus – pituitary – adrenocortical (HPA) axis. However, little is known regarding the functional adaptive changes of noradrenergic afferent innervating the PVN and supraoptic nucleus (SON) during chronic opioid exposure and upon morphine withdrawal.
Here we have studied the expression of Fos after administration of morphine and during morphine withdrawal in the rat hypothalamic PVN and SON. Fos production was also studied in brainstem regions that innervate hypothalamic nuclei: the nucleus of solitary tract (NTS – A2) and the ventrolateral medulla (VLM – A1) and combined with immunostaining for tyrosine hydroxylase (TH) for immunohistochemical identification of active neurons during morphine withdrawal. Male rats were implanted with s.c. placebo or morphine (tolerant/dependent) pellets for 7 days. On day 8 rats received an injection of saline i.p., morphine i.p., saline s.c. or naloxone s.c.
Acute morphine administration produced an increase in Fos expression at hypothalamic nuclei and in the brainstem regions, and tolerance developed towards this effect. Precipitated morphine withdrawal induced marked Fos immunoreactivity within the PVN and SON. Concomitantly, numerous neurons in the brainstem were stimulated by morphine withdrawal. Moreover, catecholaminergic‐positive neurons in the brainstem showed a significant increase in Fos expression in response to morphine withdrawal.
These findings demonstrate that chronic activation of opioid receptors results in altered patterns of immediate‐early genes (IEG) expression in the PVN and SON, which occurs concurrently with an increased activity of their inputs from the brainstem.

British Journal of Pharmacology (2002) 136, 67–75; doi:10.1038/sj.bjp.0704684
Mechanism of suppression of insulin signalling with lignocaine
Authors: Hirose Munetaka , Martyn J A Jeevendra , Kuroda Yoshihiro , Marunaka Yoshinori , Tanaka Yoshifumi 
Published: January 2005

Lignocaine suppresses insulin‐stimulated glucose transport into the cells and insulin‐stimulated glycogenesis at doses equivalent to that used in the treatment of muscle pain disorder. We evaluated the direct effect of lignocaine on insulin receptor (IR) kinase activity.
After lignocaine (40 mM, approximately equivalent to 1%) or an equal volume (100 μl) saline had been injected into the tibialis anterior muscle of rat, insulin (50 mM g−1 body weight) was administered into the portal vein in vivo. Immunoprecipitation and immunoblotting were used to detect insulin‐mediated tyrosine phosphorylation of both IR‐β and insulin receptor substrate (IRS)‐1, and insulin‐stimulated binding of IRS‐1 to p85 regulatory subunit of phosphatidylinositol 3‐kinase (PI3‐K) in the extracted muscle.
In the in vitro study, purified IR from rat liver and/or recombinant IRS‐1 protein with adenosine triphosphate were incubated with lignocaine (4 or 40 mM).
Lignocaine reduced insulin‐stimulated tyrosine phosphorylation of IR‐β to 12.6±5.7% (P<0.001), and IRS‐1 to 32.1±18.8% (P<0.01), and also reduced insulin‐stimulated binding of IRS‐1 to p85 to 27.4±12.7% (P<0.001) relative to control (100%) in muscle in vivo.
The in vitro study revealed that lignocaine directly inhibited both basal and insulin‐stimulated tyrosine phosphorylation of IR.
These results indicate that clinically used doses of lignocaine inhibit insulin signalling in skeletal muscle. The inhibitory effect of lignocaine on tyrosine kinase activity of the IR underlies the suppression of insulin signalling with lignocaine.

British Journal of Pharmacology (2002) 136, 76–80; doi:10.1038/sj.bjp.0704691
Blockade of body weight gain and plasma corticosterone levels in Zucker fatty rats using an orally active neuropeptide Y Y1 antagonist
Authors: Ishihara Akane , Kanatani Akio , Okada Megumu , Hidaka Masayasu , Tanaka Takeshi , Mashiko Satoshi , Gomori Akira , Kanno Tetsuya , Hata Mikiko , Kanesaka Maki , Tominaga Yushin , Sato Naga‐aki , Kobayashi Masahiko , Murai Takashi , Watanabe Keiko , Ishii Yasuyuki , Fukuroda Takahiro , Fukami Takehiro , Ihara Masaki 
Published: January 2005

An experiment was conducted to examine whether a potent, orally active and highly selective neuropeptide Y Y1 receptor antagonist attenuates hyperphagia and obesity in genetically obese Zucker fatty rats.
Oral administration of the Y1 antagonist (30 and 100 mg kg−1, once daily for 2 weeks) significantly suppressed the daily food intake and body weight gain in Zucker fatty rats accompanied with a reduction of fat cell size and plasma corticosterone levels.
Despite the fact that food intake was gradually returned to near the control level, the body weight of the treated animals remained significantly less when compared to that of the controls for the duration of the treatment.
These results suggest that the Y1 receptor, at least in part, participate in pathophysiological feeding and/or fat accumulation observed in Zucker fatty rats. Y1 antagonists might be useful for the treatment of obesity.

British Journal of Pharmacology (2002) 136, 341–346; doi:10.1038/sj.bjp.0704696
Protective effects of neurokinin‐1 receptor during colitis in mice: role of the epidermal growth factor receptor
Authors: Castagliuolo I , Morteau O , Keates A C , Valenick L , Wang C ‐C , Zacks J , Lu B , Gerard N P , Pothoulakis C 
Published: January 2005

The role of substance P and its high affinity neurokinin‐1 receptor in colitis has not been fully elucidated. We assessed the participation of neurokinin‐1 receptor in colitis using the 2,4,6,‐trinitrobenzensulphonic acid and dextran sulphate‐induced animal models of colitis and genetically‐engineered, neurokinin‐1 receptor‐deficient mice.
Clinical signs, macroscopic and histologic damage associated with 2,4,6,‐trinitrobenzensulphonic acid (12 days) and dextran sulphate (5 days) colitis were more severe in neurokinin‐1 deficient than in wild‐type mice, while immunoreactivities for epidermal growth factor and its receptor were similar in the colon of both mice strains before and after colitis.
Substance P, dose‐dependently induced intestinal fibroblast proliferation and enhanced epidermal growth factor‐induced proliferation in intestinal fibroblasts isolated from wild‐type, but not from neurokinin‐1 receptor deficient mice.
Substance P‐induced intestinal fibroblast proliferation required the presence of epidermal growth factor receptor with kinase activity. Furthermore, substance P induced epidermal growth factor tyrosine phosphorylation and activation in normal intestinal fibroblasts.
Our results indicate that in mice lacking the neurokinin ‐ 1 receptor, substance P plays a protective role in prolonged experimental colitis.

British Journal of Pharmacology (2002) 136, 271–279; doi:10.1038/sj.bjp.0704697