bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orphan G‐protein‐coupled receptors: the next generation of drug targets?
Authors: Wilson Shelagh , Bergsma Derk J. , Chambers Jon K. , Muir Alison I. , Fantom Kenneth G. M. , Ellis Catherine , Murdock Paul R. , Herrity Nicole C. , Stadel Jeffrey M. 
Published: January 2005

The pharmaceutical industry has readily embraced genomics to provide it with new targets for drug discovery. Large scale DNA sequencing has allowed the identification of a plethora of DNA sequences distantly related to known G protein‐coupled receptors (GPCRs), a superfamily of receptors that have a proven history of being excellent therapeutic targets. In most cases the extent of sequence homology is insufficient to assign these ‘orphan’ receptors to a particular receptor subfamily. Consequently, reverse molecular pharmacological and functional genomic strategies are being employed to identify the activating ligands of the cloned receptors. Briefly, the reverse molecular pharmacological methodology includes cloning and expression of orphan GPCRs in mammalian cells and screening these cells for a functional response to cognate or surrogate agonists present in biological extract preparations, peptide libraries, and complex compound collections. The functional genomics approach involves the use of humanized yeast cells, where the yeast GPCR transduction system is engineered to permit functional expression and coupling of human GPCRs to the endogenous signalling machinery. Both systems provide an excellent platform for identifying novel receptor ligands. Once activating ligands are identified they can be used as pharmacological tools to explore receptor function and relationship to disease.British Journal of Pharmacology (1998) 125, 1387–1392; doi:10.1038/sj.bjp.0702238
Inhibition of endothelium‐dependent hyperpolarization by endothelial prostanoids in guinea‐pig coronary artery
Authors: Yajima Kazuhiro , Nishiyama Makoto , Yamamoto Yoshimichi , Suzuki Hikaru 
Published: January 2005

In smooth muscle of the circumflex coronary artery of guinea‐pig, acetylcholine (ACh, 10−6 M) produced an endothelium‐dependent hyperpolarization consisting of two components. An initial component that occurs in the presence of ACh and a slow component that developed after ACh had been withdrawn. Each component of the hyperpolarization was accompanied by an increase in membrane conductance.
Indomethacin (5×10−6 M) or diclofenac (10−6 M), both inhibitors of cyclooxygenase, abolished only the slow hyperpolarization. The initial hyperpolarization was not inhibited by diclofenac nor by nitroarginine, an inhibitor of nitric oxide synthase.
Both components of the ACh‐induced hyperpolarization were abolished in the presence of atropine (10−6 M) or high‐K solution ([K+]0=29.4 mM).
The interval between ACh‐stimulation required to generate an initial hyperpolarization of reproducible amplitude was 20 min or greater, but it was reduced to less than 5 min after inhibiting cyclooxygenase activity. Conditioning stimulation of the artery with substance P (10−7 M) also caused a long duration (about 20 min) inhibition of the ACh‐response.
The amplitude of the hyperpolarization generated by Y‐26763, a K+‐channel opener, was reproducible within 10 min after withdrawal of ACh.
Exogenously applied prostacyclin (PGI2) hyperpolarized the membrane and reduced membrane resistance in concentrations over 2.8×10−9M.
At concentrations below threshold for hyperpolarization and when no alteration of membrane resistance occurred, PGI2 inhibited the initial component of the ACh‐induced hyperpolarization.
It is concluded that endothelial prostanoids, possibly PGI2, have an inhibitory action on the release of endothelium‐derived hyperpolarizing factor.

British Journal of Pharmacology (1999) 126, 1–10; doi:10.1038/sj.bjp.0702254
Effects of Ca2+ concentration and Ca2+ channel blockers on noradrenaline release and purinergic neuroeffector transmission in rat tail artery
Authors: Brock James A , Cunnane Thomas C 
Published: January 2005

The effects of Ca2+ concentration and Ca2+ channel blockers on noradrenaline (NA) and adenosine 5′‐triphosphate (ATP) release from postganglionic sympathetic nerves have been investigated in rat tail arteries in vitro. Intracellularly recorded excitatory junction potentials (e.j.ps) were used as a measure of ATP release and continuous amperometry was used to measure NA release.
Varying the extracellular Ca2+ concentration similarly affected the amplitudes of e.j.ps and NA‐induced oxidation currents evoked by trains of ten stimuli at 1 Hz.
The N‐type Ca2+ blocker, ω‐conotoxin GVIA (ω‐CTX GVIA, 0.1 μM) reduced the amplitudes of both e.j.ps (evoked by trains of ten stimuli at 1 Hz) and NA‐induced oxidation currents (evoked by trains of ten stimuli at 1 Hz and 50 stimuli at 10 Hz) by about 90%.
The ω‐CTX GVIA resistant e.j.ps and NA‐induced oxidation currents evoked by trains of 50 stimuli at 10 Hz were abolished by the non‐selective Ca2+ channel blocker, Cd2+ (0.1 mM), and were reduced by ω‐conotoxin MVIIC (0.5 μM) and ω‐agatoxin IVA (40 nM).
Nifedipine (10 μM) had no inhibitory effect on ω‐CTX GVIA resistant e.j.ps and NA‐induced oxidation currents.
Thus both varying Ca2+ concentration and applying Ca2+ channel blockers results in similar effects on NA and ATP release from postganglionic sympathetic nerves. These findings are consistent with the hypothesis that NA and ATP are co‐released together from the sympathetic nerve terminals.

British Journal of Pharmacology (1999) 126, 11–18; doi:10.1038/sj.bjp.0702256
Acetylcholine‐induced membrane potential changes in endothelial cells of rabbit aortic valve
Authors: Ohashi Masuo , Satoh Kohichi , Itoh Takeo 
Published: January 2005

Using a microelectrode technique, acetylcholine (ACh)‐induced membrane potential changes were characterized using various types of inhibitors of K+ and Cl− channels in rabbit aortic valve endothelial cells (RAVEC).
ACh produced transient then sustained membrane hyperpolarizations. Withdrawal of ACh evoked a transient depolarization.
High K+ blocked and low K+ potentiated the two ACh‐induced hyperpolarizations. Charybdotoxin (ChTX) attenuated the ACh‐induced transient and sustained hyperpolarizations; apamin inhibited only the sustained hyperpolarization. In the combined presence of ChTX and apamin, ACh produced a depolarization.
In Ca2+‐free solution or in the presence of Co2+ or Ni2+, ACh produced a transient hyperpolarization followed by a depolarization. In BAPTA‐AM‐treated cells, ACh produced only a depolarization.
A low concentration of A23187 attenuated the ACh‐induced transient, but not the sustained, hyperpolarization. In the presence of cyclopiazonic acid, the hyperpolarization induced by ACh was maintained after ACh removal; this maintained hyperpolarization was blocked by Co2+.
Both NPPB and hypertonic solution inhibited the membrane depolarization seen after ACh washout. Bumetanide also attenuated this depolarization.
It is concluded that in RAVEC, ACh produces a two‐component hyperpolarization followed by a depolarization. It is suggested that ACh‐induced Ca2+ release from the storage sites causes a transient hyperpolarization due to activation of ChTX‐sensitive K+ channels and that ACh‐activated Ca2+ influx causes a sustained hyperpolarization by activating both ChTX‐ and apamin‐sensitive K+ channels. Both volume‐sensitive Cl− channels and the Na+‐K+‐Cl− cotransporter probably contribute to the ACh‐induced depolarization.

British Journal of Pharmacology (1999) 126, 19–26; doi:10.1038/sj.bjp.0702262
Long term orexigenic effect of a novel melanocortin 4 receptor selective antagonist
Authors: Skuladottir Gudrun V , Jonsson Logi , Skarphedinsson Jon O , Mutulis Felikss , Muceniece Ruta , Raine Amanda , Mutule Ilze , Helgason Johannes , Prusis Peteris , Wikberg Jarl E S , Schiöth Helgi B 
Published: January 2005

We designed and synthesized several novel cyclic MSH analogues and tested their affinities for cells expressing the MC1, MC3, MC4 and MC5 receptors.
One of the substances HS028 (cyclic [AcCys11, dichloro‐D‐phenylalanine14, Cys18, Asp‐NH222]‐β‐MSH11–22) showed high affinity (Ki of 0.95nM) and high (80 fold) MC4 receptor selectivity over the MC3 receptor. HS028 thus shows both higher affinity and higher selectivity for the MC4 receptor compared to the earlier first described MC4 receptor selective substance HS014.
HS028 antagonised a α‐MSH induced increase in cyclic AMP production in transfected cells expressing the MC3 and MC4 receptors, whereas it seemed to be a partial agonist for the MC1 and MC5 receptors.
Chronic intracerebroventricularly (i.c.v.) administration of HS028 by osmotic minipumps significantly increased both food intake and body weight in a dose dependent manner without tachyphylaxis for a period of 7 days.
This is the first report demonstrating that an MC4 receptor antagonist can increase food intake and body weight during chronic administration providing further evidence that the MC4 receptor is an important mediator of long term weight homeostasis.

British Journal of Pharmacology (1999) 126, 27–34; doi:10.1038/sj.bjp.0702264
Cytokine‐mediated inflammatory hyperalgesia limited by interleukin‐4
Authors: Cunha F Q , Poole S , Lorenzetti B B , Veiga F H , Ferreira S H 
Published: January 2005

The effect of IL‐4 on responses to intraplantar (i.pl.) carrageenin, bradykinin, TNFα, IL‐1β, IL‐8 and PGE2 was investigated in a model of mechanical hyperalgesia in rats. Also, the cellular source of the IL‐4 was investigated.
IL‐4, 30 min before the stimulus, inhibited responses to carrageenin, bradykinin, and TNFα, but not responses to IL‐1β, IL‐8 and PGE2.
IL‐4, 2 h before the injection of IL‐1β, did not affect the response to IL‐1β, whereas IL‐4, 12 or 12+2 h before the IL‐1β, inhibited the hyperalgesia (−30%, −74%, respectively).
In murine peritoneal macrophages, murine IL‐4 for 2 h before stimulation with LPS, inhibited (−40%) the production of IL‐1β but not PGE2. Murine IL‐4 (for 16 h before stimulation with LPS) inhibited LPS‐stimulated PGE2 but not IL‐1β.
Anti‐murine IL‐4 antibodies potentiated responses to carrageenin, bradykinin and TNFα, but not IL‐1β and IL‐8, as well as responses to bradykinin in athymic rats but not in rats depleted of mast cells with compound 40/80.
These data suggest that IL‐4 released by mast cells limits inflammatory hyperalgesia. During the early phase of the inflammatory response the mode of action of the IL‐4 appears to be inhibition of the production TNFα, IL‐1β and IL‐8. In the later phase of the response, in addition to inhibiting the production of pro‐inflammatory cytokines, IL‐4 also may inhibit the release of PGs.

British Journal of Pharmacology (1999) 126, 45–50; doi:10.1038/sj.bjp.0702266
Interaction of amylin with calcitonin gene‐related peptide receptors in the microvasculature of the hamster cheek pouch in vivo
Authors: Hall Judith M , Brain Susan D 
Published: January 2005

This study used intravital microscopy to investigate the receptors stimulated by amylin which shares around 50% sequence homology with the vasodilator calcitonin gene‐related peptide (CGRP) in the hamster cheek pouch microvasculature in vivo.
Receptor agonists dilated arterioles (diameters 20–40 μm). The −log of the concentrations (±s.e.mean; n=8) causing 50% increase in arteriole diameter were: human βCGRP (10.8±0.3), human αCGRP (10.8±0.4), rat αCGRP (10.4±0.3). Rat amylin and the CGRP2 receptor selective agonist [Cys(ACM2,7]‐human αCGRP were 100 fold less potent (estimates were 8.5±0.4 and 8.2±0.3 respectively).
The GCRP1 receptor antagonist, CGRP8–37 (300 nmol kg−1; i.v.) reversibly inhibited the increase in diameter evoked by human αCGRP (0.3 nM) from 178±22% to 59±12% (n=8; P<0.05) and by rat amylin (100 nM) from 138±23% to 68±24% (n=6; P<0.05). CGRP8–37 did not inhibit vasodilation evoked by substance P (10 nM; n=4; P>0.05).
The amylin receptor antagonist, amylin8–37 (300 nmol kg−1; i.v.) did not significantly inhibit the increase in diameter evoked by human αCGRP (0.3 nM) which was 112±26% in the absence, and 90±29% in the presence of antagonist (n=4; P<0.05); nor that evoked by rat amylin (100 nM) which was 146±23% in the absence and 144±32% in the presence of antagonist (n=4; P>0.05).
The agonist profile for vasodilatation and the inhibition of this dilatation by CGRP8–37, although not the amylin8–37 indicates that amylin causes vasodilatation through interaction with CGRP1 receptors in the hamster cheek pouch.

British Journal of Pharmacology (1999) 126, 280–284; doi:10.1038/sj.bjp.0702272
Specific inhibition of ADP‐induced platelet aggregation by clopidogrel in vitro
Authors: Weber Artur‐Aron , Reimann Stephanie , Schrör Karsten 
Published: January 2005

The thienopyridine clopidogrel is a specific inhibitor of ADP‐induced platelet aggregation ex vivo. No direct effects of clopidogrel (100 μM) on platelet aggregation in vitro have been described so far.
Possible in vitro antiaggregatory effects (turbidimetry) of clopidogrel were studied in human platelet‐rich plasma and in washed platelets.
Incubation of platelet‐rich plasma with clopidogrel (100 μM) for up to 8 h did not result in any inhibition of ADP (6 μM)‐induced platelet aggregation.
Incubation of washed platelets with clopidogrel resulted in a time‐ (maximum effects after 30 min) and concentration‐dependent (IC50 1.9±0.3 μM) inhibition of ADP (6 μM)‐induced platelet aggregation. Clopidogrel (30 μM) did not inhibit collagen (2.5 μg ml−1)‐, U46619 (1 μM)‐ or thrombin (0.1 u ml−1)‐induced platelet aggregation. The inhibition of ADP‐induced aggregation by clopidogrel (30 μM) was insurmountable indicating a non‐equilibrium antagonism of ADP actions. The R enantiomer SR 25989 C (30 μM) was significantly less active than clopidogrel (30 μM) in inhibiting platelet aggregation (32±5 % vs 70±1 % inhibition, P<0.05, n=5).
In washed platelets, clopidogrel (30 μM) did not significantly reverse the inhibition of prostaglandin E1 (1 μM)‐induced platelet cyclic AMP formation by ADP (6 μM).
The antiaggregatory effects of clopidogrel were unchanged when the compound was removed from the platelet suspension. However, platelet inhibition by clopidogrel was completely abolished when albumin (350 mg ml−1) was present in the test buffer.
It is concluded that clopidogrel specifically inhibits ADP‐induced aggregation of washed platelets in vitro without hepatic bioactivation. Inhibition of ADP‐induced platelet aggregation by clopidogrel in vitro occurs in the absence of measurable effects on the reversal of PGE1‐stimulated cyclic AMP by ADP.

British Journal of Pharmacology (1999) 126, 415–420; doi:10.1038/sj.bjp.0702276
NMDA receptor characterization and subunit expression in rat cultured mesencephalic neurones
Authors: Allgaier C , Scheibler P , Müller D , Feuerstein T J , Illes P 
Published: January 2005

NMDA‐induced changes in free intracellular Ca2+ concentration ([Ca2+]i) were determined in individual cultured rat mesencephalic neurones by the fura‐2 method. mRNA expression encoding NMDA receptor subunits (NR1, NR2A‐D) was examined by RT–PCR.
NMDA (1–100 μM, plus 10 μM glycine) induced a concentration‐dependent increase in [Ca2+]i (EC50=5.7 μM). The effect of NMDA was virtually insensitive to tetrodotoxin (0.3 μM) and nitrendipine (1 μM), but dependent on extracellular Ca2+. 5,7‐Dichlorokynurenic acid (10 μM), a specific antagonist at the glycine binding site on the NMDA receptor, abolished the NMDA response.
Memantine, an open‐channel blocker, and ifenprodil, a preferential non‐competitive NR1/NR2B receptor antagonist diminished the NMDA effect with an IC50 value of 0.17 and 1 μM, respectively. Ethanol at 50 and 100 mM caused about 25 and 45%‐inhibition, respectively.
Agarose gel analysis of the PCR products followed by ethidium bromide fluorescence or CSPD chemiluminescence detection revealed an almost exclusive expression of the NR1 splice variants lacking exon (E) 5 and E22. The 3′ splice form without both E21 and E22 exceeded that containing E21 by approximately 4 fold. The relative amounts of NR2A, NR2B, NR2C corresponded to approximately 1:2:1. NR2D mRNA was also detectable.
In conclusion, mesencephalic neurones bear ethanol‐sensitive NMDA receptors which might be involved in the development of ethanol dependence and withdrawal. The high affinity of NMDA to this receptor, its sensitivity to ifenprodil and memantine may suggest that the mesencephalic NMDA receptor comprises the NR1 splice variant lacking E5, NR2B, and NR2C, respectively.

British Journal of Pharmacology (1999) 126, 121–130; doi:10.1038/sj.bjp.0702284
Formal analysis of electrogenic sodium, potassium, chloride and bicarbonate transport in mouse colon epithelium
Authors: Cuthbert A W , Hickman M E , MacVinish L J 
Published: January 2005

The mammalian colonic epithelium carries out a number of different transporting activities simultaneously, of which more than one is increased following activation with a single agonist. These separate activities can be quantified by solving a set of equations describing these activities, provided some of the dependent variables can be eliminated. Using variations in the experimental conditions, blocking drugs and comparing wild type tissues with those from transgenic animals this has been achieved for electrogenic ion transporting activity of the mouse colon.
Basal activity and that following activation with forskolin was measured by short circuit current in isolated mouse colonic epithelia from normal and cystic fibrosis (CF) mice.
Using amiloride it is shown that CF colons show increased electrogenic sodium absorption compared to wild type tissues. CF mice had elevated plasma aldosterone, which may be responsible for part or all of the increased sodium absorbtion in CF colons.
The derived values for electrogenic chloride secretion and for electrogenic potassium secretion were increased by 13 and 3 fold respectively by forskolin, compared to basal state values for these processes.
The loop diuretic, frusemide, completely inhibited electrogenic potassium secretion, but apparently only partially inhibited electrogenic chloride secretion. However, use of bicarbonate‐free solutions and acetazolamide reduced the frusemide‐resistant current, suggesting that electrogenic bicarbonate secretion accounts for the frusemide‐resistant current.
It is argued that the use of tissues from transgenic animals is an important adjunct to pharmacological analysis, especially where effects in tissues result in the activation of more than one sort of response.

British Journal of Pharmacology (1999) 126, 358–364; doi:10.1038/sj.bjp.0702290
Identification of a region of the C‐terminal domain involved in short‐term desensitization of the prostaglandin EP4 receptor
Authors: Bastepe Murat , Ashby Barrie 
Published: January 2005

The prostaglandin EP4 receptor, which couples to stimulation of adenylyl cyclase, undergoes rapid agonist‐induced desensitization when expressed in CHO‐K1 cells.
Truncation of the 488‐amino acid receptor at residue 350 removes the carboxy‐terminal domain and abolishes desensitization.
To further delineate residues involved in desensitization, the receptor was truncated at position 408, 383 or 369. Receptors truncated at position 408 or 383 underwent PGE2‐induced desensitization, whereas the receptor truncated at position 369 displayed sustained activity, indicating that the essential residues for desensitization lie between 370 and 383.
The six serines in the 14‐amino acid segment between residues 370 and 383 were mutated to alanine, retaining the entire C‐terminal domain. Desensitization was absent in cells expressing this mutant.
The results indicate involvement of serines located between 370 and 382 in rapid desensitization of the EP4 receptor.

British Journal of Pharmacology (1999) 126, 365–371; doi:10.1038/sj.bjp.0702291
[3H]‐Mesulergine labels 5‐HT7 sites in rat brain and guinea‐pig ileum but not rat jejunum
Authors: Hemedah Maggie , Coupar Ian M , Mitchelson Fred J 
Published: January 2005

The primary aim of this investigation was to determine whether binding sites corresponding to the 5‐HT7 receptor could be detected in smooth muscle of the rat jejunum. Binding studies in rat brain (whole brain minus cerebellum) and guinea‐pig ileal longitudinal muscle were also undertaken in order to compare the binding characteristics of these tissues. Studies were performed using [3H]‐mesulergine, as it has a high affinity for 5‐HT7 receptors.
In the rat brain and guinea‐pig ileum, pKD values for [3H]‐mesulergine of 8.0±0.04 and 7.9±0.11 (n=3) and Bmax values of 9.9±0.3 and 21.5±4.9 fmol mg−1 protein were obtained respectively, but no binding was detected in the rat jejunum. [3H]‐mesulergine binding in the rat brain and guinea‐pig ileum was displaced with the agonists 5‐carboxamidotryptamine (5‐CT)>5‐hydroxytryptamine (5‐HT)5‐methoxytryptamine (5‐MeOT)>sumatriptan and the antagonists risperidoneLSDmetergoline>ritanserin>>pindolol.
Despite the lack of [3H]‐mesulergine binding in the rat jejunum, functional studies undertaken revealed a biphasic contractile response to 5‐HT which was partly blocked by ondansetron (1 μM). The residual response was present in over 50% of tissues studied and was found to be inhibited by risperidone>LSD>metergoline>mesulergine=ritanserin>pindolol, but was unaffected by RS 102221 (3 μM), cinanserin (30 nM), yohimbine (0.1 μM) and GR 113808 (1 μM). In addition, the agonist order of potency was 5‐CT>5‐HT>5‐MeOT>sumatriptan.
In conclusion, binding studies performed with [3H]‐mesulergine were able to detect 5‐HT7 sites in rat brain and guinea‐pig ileum, but not in rat jejunum, where a functional 5‐HT7‐like receptor was present.

British Journal of Pharmacology (1999) 126, 179–188; doi:10.1038/sj.bjp.0702293
Reduction of sodium deoxycholic acid‐induced scratching behaviour by bradykinin B2 receptor antagonists
Authors: Hayashi Izumi , Majima Masataka 
Published: January 2005

Subcutaneous injection of sodium deoxycholic acid into the anterior of the back of male ddY mice elicited dose‐dependent scratching of the injected site with the forepaws and hindpaws.
Up to 100 μg of sodium deoxycholic acid induced no significant increase in vascular permeability at the injection site as assessed by a dye leakage method.
Bradykinin (BK) B2 receptor antagonists, FR173657 and Hoe140, significantly decreased the frequency of scratching induced by sodium deoxycholic acid.
Treatment with aprotinin to inhibit tissue kallikrein reduced the scratching behaviour induced by sodium deoxycholic acid, whereas treatment with soybean trypsin inhibitor to inhibit plasma kallikrein did not.
Although injection of kininase II inhibitor, lisinopril together with sodium deoxycholic acid did not alter the scratching behaviour, phosphoramidon, a neutral endopeptidase inhibitor, significantly increased the frequency of scratching.
Homogenates of the skin excised from the backs of mice were subjected to gel‐filtration column chromatography followed by an assay of kinin release by trypsin from each fraction separated. Less kinin release from the fractions containing kininogen of low molecular weight was observed in the skin injected with sodium deoxycholic acid than in normal skin.
The frequency of scratching after the injection of sodium deoxycholic acid in plasma kininogen‐deficient Brown Norway Katholiek rats was significantly lower than that in normal rats of the same strain, Brown Norway Kitasato rats.
These results indicate that BK released from low‐molecular‐weight kininogen by tissue kallikrein, but not from high‐molecular‐weight kininogen by plasma kallikrein, may be involved in the scratching behaviour induced by the injection of sodium deoxycholic acid in the rodent.

British Journal of Pharmacology (1999) 126, 197–204; doi:10.1038/sj.bjp.0702296