bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human P2Y2 receptor polymorphism: identification and pharmacological characterization of two allelic variants
Authors: Janssens Rodolphe , Paindavoine Pascale , Parmentier Marc , Boeynaems Jean‐Marie 
Published: January 2005

In the process of cloning the human P2Y2 receptor in order to establish 1321N1 cell lines expressing this receptor, we detected a gene polymorphism characterized by an arginine 334 to cysteine 334 transition.
The frequency distribution of the polymorphism was studied in a European population. We observed that 66% of the tested persons are homozygotes R/R, 29% are heterozygotes R/C and 5% are homozygotes C/C. The frequency of the R allele was 0.8 versus 0.2 for the C allele.
We stably expressed each form of the human P2Y2 receptor into 1321N1 cells and isolated clones by limiting dilution. The effects of nucleotides and antagonists on inositol trisphosphate accumulation and cyclic AMP formation were compared between the two cell lines.
The time‐courses of inositol trisphosphate accumulation as well as concentration‐response curves characterizing the effects of UTP, ATP, AP4A and ATPγS were mostly similar, except for slight kinetic differences (slower time‐course with the 334C form).
The sensitivity to pertussis toxin of inositol trisphosphates accumulation was critically dependent on the agonist concentration and stimulation duration, suggesting the involvement of a Gi,0 protein during the early stimulation by low nucleotide concentrations. No inhibition of cyclic AMP accumulation could be detected. These properties were observed with both polymorphic receptors.

British Journal of Pharmacology (1999) 127, 709–716; doi:10.1038/sj.bjp.0702619
Characterization of central and peripheral effects of septide with the use of five tachykinin NK1 receptor antagonists in the rat
Authors: Cellier Eric , Barbot Lionel , Iyengar Smriti , Couture Réjean 
Published: January 2005

Effects of two tachykinin NK1 receptor selective agonists (septide and [Sar9, Met(O2)11]SP) were compared on the increases in mean arterial pressure (MAP), heart rate (HR) and motor behaviour following intracerebroventricular (i.c.v.) administration in unanaesthetized rat, and on the vascular permeability increases to intradermal (i.d.) injection in the anaesthetized rat. Moreover, five tachykinin NK1 receptor selective antagonists (LY303870, LY306740, LY303241, SR140333 and RP67580) were tested against the two agonists to compare their pharmacological profile.
[Sar9, Met(O2)11]SP and septide (10–100 pmol per rat, i.c.v.) were equipotent in increasing MAP and HR, yet they had dissimilar time‐course. Both agonists increased dose‐dependently face washing and sniffing while [Sar9, Met(O2)11]SP was the sole to produce grooming. septide was more potent than [Sar9, Met(O2)11]SP (6.5–650 pmol) in increasing vascular permeability.
For most centrally mediated responses, LY303870 and RP67580 were significantly more potent in inhibiting septide than [Sar9, Met(O2)11]SP. In some parameters, greater blockade was achieved when antagonists (particularly LY306740) were given 1 h instead of 10 min prior to i.c.v. septide.
All antagonists except LY303241 blocked dose‐dependently the increases in vascular permeability to equipotent doses of [Sar9, Met(O2)11]SP and septide. LY303870 and LY306740 were more potent against septide.
The antagonism afforded by LY303870, LY306740 and LY303241 was stereoselective and only SR140333 was found to cause central and peripheral non specific effects.
The data confirm a distinct pharmacological profile for septide in vivo. RP67580 and LY306740 are currently the most valuable tachykinin NK1 receptor antagonists for in vivo studies in rat.

British Journal of Pharmacology (1999) 127, 717–728; doi:10.1038/sj.bjp.0702620
Studies on the role of serotonin receptor subtypes in the effect of sibutramine in various feeding paradigms in rats
Authors: Grignaschi G , Fanelli E , Scagnol I , Samanin R 
Published: January 2005

The effect of the 5‐hydroxytryptamine (5‐HT) and noradrenaline (NA) reuptake inhibitor sibutramine was studied in food deprived, neuropeptide Y (NPY)‐ or muscimol‐injected rats.
Sibutramine dose‐dependently reduced feeding caused by food‐deprivation (ED50=5.1±0.8 mg kg−1) or by NPY injection into the paraventricular nucleus of the hypothalamus (ED50=6.0±0.5 mg kg−1). The increase in food intake caused by muscimol injected into the dorsal raphe was not modified by sibutramine (1–10 mg kg−1).
The hypophagic effect of 5.1 mg kg−1 sibutramine in food‐deprived rats was studied in rats pretreated with different serotonin receptor antagonists. Metergoline (non‐selective, 0.3 and 1.0 mg kg−1), ritanserin (5‐HT2A/2C, 0.5 and 1.0 mg kg−1) and GR127935 (5‐HT1B/1D, 0.5 and 1.0 mg kg−1) did not modify the hypophagic effect of sibutramine, while SB206553 (5‐HT2B/2C, 5 and 10 mg kg−1) slightly but significantly reduced it (Fint(2.53)=3.4; P<0.05).
The reduction in food intake caused by 6.0 mg kg−1 sibutramine in NPY‐injected rats was not modified by GR127935 (1.0 mg kg−1).
The results suggest that, with the possible exception of a partial involvement of 5‐HT2B/2C receptors in sibutramine's hypophagia in food‐deprived rats, 5‐HT1 and 5‐HT2 receptor subtypes do not play an important role in the hypophagic effect of sibutramine, at least in the first 2 h after injection.

British Journal of Pharmacology (1999) 127, 1190–1194; doi:10.1038/sj.bjp.0702633
Influence of the endothelium, nitric oxide and serotonergic receptors on coronary vasomotor responses evoked by ergonovine in conscious dogs
Authors: Karila‐Cohen Daniel , Delpy Eric , Dubois‐Randé Jean‐Luc , Puybasset Louis , Hittinger Luc , Giudicelli Jean‐François , Berdeaux Alain 
Published: January 2005

The respective contributions of coronary vascular endothelium, nitric oxide (NO) and serotonergic receptors to the effects of ergonovine on large and small coronary arteries were investigated in conscious dogs.
In seven dogs with an endothelium intact, ergonovine (30–1000 μg, i.v.) induced a biphasic response on large coronary artery with an early and transient vasodilatation (up to +2.9±0.5% from 3310±160 μm, P<0.01) followed by a sustained vasoconstriction (down to −4.9±0.5%, P<0.001) which occurred simultaneously with a sustained increase in coronary blood flow (CBF) (up to +100±26% from 28±4 ml min−1, P<0.001). After endothelium removal (balloon angioplasty), the ergonovine‐induced vasodilatation was abolished and vasoconstriction potentiated (−6.4±0.9% after vs −4.9±0.5% before endothelium removal, P<0.01).
After blockade of NO synthesis by Nω‐nitro‐L‐arginine (30 mg kg−1) in four other dogs, the early vasodilatation induced by ergonovine was abolished but the delayed vasoconstriction as well as the increase in CBF remained unchanged.
Both ketanserin and methiothepin (0.3 mg kg−1) abolished the early vasodilatation and reduced the delayed vasoconstriction induced by ergonovine. Ketanserin decreased and methiothepin abolished the reduction in coronary resistance induced by ergonovine.
Thus, the complex interactions between vascular endothelium and serotonergic receptors to ergonovine‐induced constriction of large coronary arteries might explain the induction of coronary spasms in patients with endothelial dysfunction.

British Journal of Pharmacology (1999) 127, 1039–1047; doi:10.1038/sj.bjp.0702635
The contribution of intracellular Ca2+release to contraction in human bladder smooth muscle
Authors: Masters J G , Neal D E , Gillespie J I 
Published: January 2005

The importance of Ca2+ release from the sarcoplasmic reticulum (SR) in excitation contraction (EC) coupling in human detrusor muscle remains controversial. In this paper the contribution of Ca2+ release to agonist induced contraction is assessed.
Dose response curves to carbachol (0.01–10 μM) were constructed before and after exposure to 200 nM Thapsigargin (Tg). Tg pre‐treatment reduced the force of contraction at all agonist concentrations however, the reduction was dose dependent. At 0.1 μM the contractions were reduced to 14.5±7% (mean±s.e.mean) of controls (n=8) while at 10 μM the contractions were only reduced to 92±3% of controls (n=10).
The role of external Ca2+ was examined by measuring the magnitude of contraction to low and high doses of agonist in the presence and absence of external Ca2+. With (0.1–0.3 μM) carbachol the contractions in nominally Ca2+ free media were 4±4% of controls (n=7) whilst with (1–10 μM) carbachol the contractions were 36±8% of controls (n=7) suggesting that at low agonist concentrations the release of Ca2+ has a requirement for external Ca2+.
Pre‐treatment of muscle strips with the Ca2+ channel blocking agent diltiazem reduced the contractile responses to carbachol. Contractions induced by 0.1 μM were reduced to 29±11% (P<0.05) of controls while those activated by 10 μM were reduced to 86±6% (P=0.1) of controls (n=4) suggesting the Ca2+ influx needed to activate internal store release at low agonist stimulation is through L‐type Ca2+ channels.
These observations confirm the importance of thapsigargin sensitive intracellular Ca2+ store release in the activation of contraction of detrusor smooth muscle and suggest the overall contribution of this store depends upon the magnitude of the agonist stimulation.

British Journal of Pharmacology (1999) 127, 996–1002; doi:10.1038/sj.bjp.0702640
Subtype‐selective inhibition of [methyl‐3H]‐N‐methylscopolamine binding to muscarinic receptors by α‐truxillic acid esters
Authors: Lysíková Michaela , Fuksová Květa , Elbert Tomáš , Jakubík Jan , Tuček Stanislav 
Published: January 2005

Seven esters of α‐truxillic acid have been synthesized: bis‐3‐piperidylpropyl ester and its quaternary bis‐N‐ethyl derivative, bis‐N‐diethylaminopropyl ester and its quaternary bis‐N‐methyl derivative, and bis‐4‐piperidylbutyl ester and its quaternary bis‐N‐methyl and bis‐N‐ethyl derivatives.
All esters inhibited the specific binding of muscarinic receptor antagonist [methyl‐3H]‐N‐methylscopolamine ([3H]‐NMS) to muscarinic receptors in membranes of CHO cell lines stably expressing the human gene for the M1, M2, M3 or M4 subtype of muscarinic receptors. All esters displayed the highest potency at the M2 and the lowest potency at the M3 receptor subtype.
In experiments performed on the M2 muscarinic receptor subtype, the affinity between the receptors and the esters was greatly increased when the concentration of ions was diminished. The highest affinities were found for the tertiary bis‐3‐piperidylpropyl and bis‐4‐piperidylbutyl aminoesters (equilibrium dissociation constants of 52 and 179 pM, respectively, in the low ionic strength medium).
All investigated esters slowed down the dissociation of [3H]‐NMS from the M2 muscarinic receptor subtype. [3H]‐NMS dissociation from the M1, M3 and M4 muscarinic receptor subtypes was investigated in experiments with the bis‐4‐piperidylbutyl aminoester and also found to be decelerated.
It is concluded that the esters of α‐truxillic acid act as M2‐selective allosteric modulators of muscarinic receptors and that, by their potency, the tertiary bis‐3‐piperidylpropyl and bis‐4‐piperidylbutyl aminoesters surpass the other known allosteric modulators of these receptors.

British Journal of Pharmacology (1999) 127, 1240–1246; doi:10.1038/sj.bjp.0702646
Prejunctional angiotensin receptors involved in the facilitation of noradrenaline release in mouse tissues
Authors: Cox S L , Trendelenburg A U , Starke K 
Published: January 2005

The effect of angiotensin II, angiotensin III, angiotensin IV and angiotensin‐(1–7) on the electrically induced release of noradrenaline was studied in preparations of mouse atria, spleen, hippocampus, occipito‐parietal cortex and hypothalamus preincubated with [3H]‐noradrenaline. The prejunctional angiotensin receptor type was investigated using the non‐selective receptor antagonist saralasin (AT1/AT2) and the AT1 and AT2 selective receptor antagonists losartan and PD 123319, respectively.
In atrial and splenic preparations, angiotensin II (0.01 nM–0.1 μM) and angiotensin III (0.01 and 0.1 nM–1 μM) increased the stimulation‐induced overflow of tritium in a concentration‐dependent manner. Angiotensin IV, only at high concentrations (1 and 10 μM), enhanced tritium overflow in the atria, while angiotensin‐(1–7) (0.1 nM–10 μM) was without effect in both preparations.
In preparations of hippocampus, occipito‐parietal cortex and hypothalamus, none of the angiotensin peptides altered the evoked overflow of tritium.
In atrial and splenic preparations, saralasin (0.1 μM) and losartan (0.1 and 1 μM), but not PD 123319 (0.1 μM), shifted the concentration‐response curves of angiotensin II and angiotensin III to the right.
In conclusion, in mouse atria and spleen, angiotensin II and angiotensin III facilitate the action potential induced release of noradrenaline via a prejunctional AT1 receptor. Only high concentrations of angiotensin IV are effective in the atria and angiotensin‐(1–7) is without effect in both preparations. In mouse brain areas, angiotensin II, angiotensin III, angiotensin IV and angiotensin‐(1–7) do not modulate the release of noradrenaline.

British Journal of Pharmacology (1999) 127, 1256–1262; doi:10.1038/sj.bjp.0702652
Quantitation of extracellular UTP using a sensitive enzymatic assay
Authors: Lazarowski Eduardo R , Harden T Kendall 
Published: January 2005

The wide distribution of the uridine nucleotide‐activated P2Y2, P2Y4 and P2Y6 receptors suggests a role for UTP as an important extracellular signalling molecule. However, direct evidence for UTP release and extracellular accumulation has been addressed only recently due to the lack of a sensitive assay for UTP mass. In the present study, we describe a method that is based on the uridinylation of [14C]‐glucose‐1P by the enzyme UDP‐glucose pyrophosphorylase which allows quantification of UTP in the sub‐nanomolar concentration range.
The UTP‐dependent conversion of [14C]‐glucose‐1P to [14C]‐UDP‐glucose was made irreversible by including the pyrophosphate scavenger inorganic pyrophosphatase in the reaction medium and [14C]‐glucose‐1P and [14C]‐UDP‐glucose were separated and quantified by HPLC. Formation of [14C]‐UDP‐glucose was linearly observed between 1 and 300 nM UTP. The reaction was highly specific for UTP and was unaffected by a 1000 fold molar excess of ATP over UTP.
Release of UTP was measured with a variety of cells including platelets and leukocytes, primary airway epithelial cells, rat astrocytes and several cell lines. In most resting attached cultures, extracellular UTP concentrations were found in the low nanomolar range (1–10 nM in 0.5 ml medium bathing 2.5 cm2 dish). Up to a 20 fold increase in extracellular UTP levels was observed in cells subjected to a medium change. Extracellular UTP levels were 10–30% of the ATP levels in both resting and mechanically‐stimulated cultured cells. In unstirred platelets, a 1 : 100 ratio UTP/ATP was observed. Extracellular UTP and ATP increased 10 fold in thrombin‐stimulated platelets.
Detection of UTP in nanomolar concentrations in the medium bathing resting cultures suggests that constitutive release of UTP may provide a mechanism of regulation of the basal activity of uridine nucleotide sensitive receptors.

British Journal of Pharmacology (1999) 127, 1272–1278; doi:10.1038/sj.bjp.0702654
Multiple effector pathways regulate the insulin secretory response to the imidazoline RX871024 in isolated rat pancreatic islets
Authors: Mourtada Mirna , Chan Sue L F , Smith Stephen A , Morgan Noel G 
Published: January 2005

When isolated rat islets were cultured for 18 h prior to use, the putative imidazoline binding site ligand, RX871024 caused a dose‐dependent increase in insulin secretion at both 6 mM and 20 mM glucose. By contrast, a second ligand, efaroxan, was ineffective at 20 mM glucose whereas it did stimulate insulin secretion in response to 6 mM glucose.
Exposure of islets to RX871024 (50 μM) for 18 h, resulted in loss of responsiveness to this reagent upon subsequent re‐exposure. However, islets that were unresponsive to RX871024 still responded normally to efaroxan.
The imidazoline antagonist, KU14R, blocked the insulin secretory response to efaroxan, but failed to prevent the stimulatory response to RX871024.
By contrast with its effects in cultured islets, RX871024 inhibited glucose‐induced insulin release from freshly isolated islets. Efaroxan did not inhibit insulin secretion under any conditions studied.
In freshly isolated islets, the effects of RX871024 on insulin secretion could be converted from inhibitory to stimulatory, by starvation of the animals.
Inhibition of insulin secretion by RX871024 in freshly isolated islets was prevented by the cyclo‐oxygenase inhibitors indomethacin or flurbiprofen. Consistent with this, RX871024 caused a marked increase in islet PGE2 formation. Efaroxan did not alter islet PGE2 levels.
The results suggest that RX871024 exerts multiple effects in the pancreatic β‐cell and that its effects on insulin secretion cannot be ascribed only to interaction with a putative imidazoline binding site.

British Journal of Pharmacology (1999) 127, 1279–1287; doi:10.1038/sj.bjp.0702656
Suc‐[Glu9, Ala11,15]‐endothelin‐1 (8–21), IRL 1620, identifies two populations of ETB receptors in guinea‐pig bronchus
Authors: Mazzoni Maria R , Breschi M Cristina , Ceccarelli Francesca , Lazzeri Nicola , Giusti Laura , Nieri Paola , Lucacchini Antonio 
Published: January 2005

The pharmacological properties of endothelin receptors (ETR) were investigated in guinea‐pig bronchus by comparing binding and functional results.
In binding assays, both the ETB agonists, endothelin‐3 (ET‐3) and N‐suc‐[Glu9,Ala11,15]ET‐1(8–21) (IRL 1620), and the antagonist, N‐cis‐2,6‐dimethylpiperidinocarbonyl‐L‐γ‐methylleucyl‐D‐1‐methoxycarbonyltryptophanyl‐D‐norleucine (BQ 788), showed biphasic inhibition curves of [125I]‐endothelin‐1 (ET‐1) binding to bronchus membranes prepared from intact or epithelium‐deprived tissue. IRL 1620 did not completely displace specifically [125I]‐ET‐1 bound to these tissue preparations. In the presence of the ETA‐selective antagonist, cyclo(‐D‐Trp‐D‐Asp‐L‐Pro‐D‐Val‐L‐Leu) (BQ 123, 1 μM), IRL 1620 displacement curves were shallow but a complete inhibition was reached at a concentration of 1 μM. Both curves were better represented by two‐site models. In addition, BQ 788 competition curves became monophasic when binding experiments were performed in the presence of 1 μM BQ 123. The non‐selective agonist, ET‐1, and BQ 123 inhibited [125I]‐ET binding to bronchus membranes in dose‐dependent fashions with monophasic curves.
The contracting activity of IRL 1620 (0.55 nM–1.6 μM) was tested on multiple‐ring bronchial preparations pretreated with peptidase and cyclo‐oxygenase inhibitors. BQ 788 shifted IRL1620 concentration‐response curves to the right while BQ 123 did not influence bronchial responsiveness. In addition, a potentiation of the maximal response to the agonist was observed in BQ 788 treated bronchial rings. This effect was abolished by tissue pretreatment with Nω‐nitro‐L‐argininemethylester (L‐NAME) or epithelium removal but not by pretreatment with atropine or iberiotoxin.
Our results demonstrate that guinea‐pig bronchus contains two populations of ETB receptors with different affinities for the ETB‐selective agonist, IRL 1620. One ETB receptor population appears to activate bronchial muscle contraction while another on epithelial cells causes muscle relaxation through the release of nitric oxide (NO).

British Journal of Pharmacology (1999) 127, 1406–1414; doi:10.1038/sj.bjp.0702672
Antagonism of the mGlu5 agonist 2‐chloro‐5‐hydroxyphenylglycine by the novel selective mGlu5 antagonist 6‐methyl‐2‐(phenylethynyl)‐pyridine (MPEP) in the thalamus
Authors: Salt T E , Binns K E , Turner J P , Gasparini F , Kuhn R 
Published: January 2005

Our previous work has shown that Group I mGlu receptors participate in thalamic sensory processing in vivo. However, unequivocal demonstration of mGlu5 participation has not been possible due to the lack of specific ligands. We have therefore made a preliminary study of the in vivo actions of the agonist (R,S)‐2‐Chloro‐5‐hydroxyphenylglycine [CHPG] and the novel mGlu5 antagonist 6‐methyl‐2‐(phenylethynyl)‐pyridine [MPEP] in order to characterize their suitability for functional studies. Iontophoretically administered MPEP selectively antagonized excitatory responses of single rat thalamic neurones to CHPG compared to the broad‐spectrum mGlu agonist (1S,3R)‐1‐aminocyclopentane‐1,3‐dicarboxylate. In contrast, the established mGlu1 and mGlu5 antagonist (S)‐4‐carboxyphenylglycine reduced responses to both agonists. These findings are the first demonstration of an in vivo action of CHPG and its antagonism by a selective mGlu5 antagonist. Furthermore MPEP appears to be a good tool for functional studies of mGlu5.British Journal of Pharmacology (1999) 127, 1057–1059; doi:10.1038/sj.bjp.0702677
Spontaneously hypertensive rats cholinergic hyper‐responsiveness: central and peripheral pharmacological mechanisms
Authors: Lazartigues E , Brefel‐Courbon C , Tran M A , Montastruc J L , Rascol O 
Published: January 2005

The mechanisms and the subtypes of muscarinic receptors implicated in the cardiovascular effects of physostigmine were investigated in conscious normotensive and spontaneously hypertensive rats.
Intravenous (i.v.) physostigmine (50 μg kg−1) induced in both strains a long pressor response, accompanied by a bradycardia. This pressor response was larger in spontaneously hypertensive (+41±6 mmHg) than in Wistar‐Kyoto (+25±2 mmHg) rats (P<0.05).
Pretreatment with atropine sulphate (0.4 mg kg−1 i.v.), completely abolished the physostigmine‐induced pressor response in both normotensive and hypertensive rats. In both strains, the physostigmine pressor response was significantly reduced by the systemic administration of either an α1‐adrenoceptor antagonist (prazosin, 1 mg kg−1) or a V1A‐vasopressin receptor antagonist (AVPX, 20 μg kg−1). This physostigmine pressor effect was completely abolished in both strains when both antagonists were administered concomitantly.
In WKY rats, the pressor response to physostigmine (50 μg kg−1 i.v.) was inhibited in a dose‐dependent manner by i.c.v. administration of atropine (ID50=3.70 nmoles), the M1 receptor antagonist pirenzepine (ID50=10.71 nmoles), the M2 receptor antagonist methoctramine (ID50=4.31 nmoles), the M3 receptor antagonist p‐F‐HHSiD (ID50=60.52 nmoles) and the M4 receptor antagonist tropicamide (ID50=214.20 nmoles). In the hypertensive strain, the ID50 were found to be significantly higher for atropine (7.34 nmoles), pirenzepine (21.60 nmoles) and p‐F‐HHSiD (139.50 nmoles) (P<0.05).
The present results indicate that physostigmine acts in normotensive and spontaneously hypertensive rats, through stimulation of both central M2 and M1 cholinoceptors to induce a rise in blood pressure mediated by an increase in plasma vasopressin and sympathetic outflow. Moreover, our results suggest that some modifications of the M1 receptor subtypes in terms of expression or affinity could be responsible for the hyper‐responsiveness of the hypertensive strain to cholinomimetic agents.

British Journal of Pharmacology (1999) 127, 1657–1665; doi:10.1038/sj.bjp.0702678