bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nitric oxide on proliferation and differentiation of rat brown adipocytes in primary cultures
Authors: Nisoli Enzo , Clementi Emilio , Tonello Cristina , Sciorati Clara , Briscini Luca , Carruba Michele O 
Published: January 2005

In the present work, we study the effect of NO on the proliferation and differentiation of brown fat cells in primary cultures.
Brown fat precursor cells isolated from rat brown adipose tissue were cultured for 8 days until confluence and treated daily with the NO donating agents, S‐nitroso‐acetyl penicillamine (SNAP) or S‐nitroso‐L‐glutathione (GSNO). Both agents (300 μM) decreased cell proliferation approximately 8 fold on day 8. The inhibitory effect of NO was unlikely to be due to cytotoxicity since (i) cells never completely lost their proliferation capacity even after 8 days of exposure to repeated additions of SNAP or GSNO, and (ii) the inhibitory effect was reversible after removal of the media containing NO donors.
Daily treatment with nitric oxide synthase inhibitors, such as NG‐nitro‐L‐arginine methyl ester (L‐NAME, 300 μM), led to the stimulation of cell proliferation by 44±5%, n=3, suggesting that NO, endogenously produced in brown adipocytes, may be involved in modulating cell growth.
Daily treatment with both SNAP or GSNO induced significant mitochondriogenesis, measured as the mitochondrial conversion of 3‐[4,5‐dimethylthiazol‐2‐yl‐]‐2,5‐diphenyl tetrazolium bromide (MTT) to formazan, whilst daily treatment with L‐NAME was without effect.
The inhibition of cell proliferation by NO donors was accompanied by the expression of two genes coding for peroxisome proliferator activated receptor‐γ and uncoupling protein‐1, which are upregulated during differentiation.
Increasing cyclic GMP in cells by 8‐bromo‐cyclic GMP (100–1000 μM) did not reproduce the observed NO effects on either cell number or gene expression. On the other hand, chronic treatment with the inhibitor of the NO‐stimulated guanylyl cyclase, 1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one (ODQ), reduced the expression of peroxisome proliferator activated receptor‐γ and uncoupling protein‐1.

British Journal of Pharmacology (1998) 125, 888–894; doi:10.1038/sj.bjp.0702131
A partial involvement of histamine in ultrasonically nebulized distilled water‐induced bronchoconstriction in guinea‐pigs
Authors: Fujimura Masaki , Amemiya Tokunao , Myou Shigeharu , Ishiura Yoshihisa , Sasaki Shigeki , Matsuda Tamotsu 
Published: January 2005

Inhalation of ultrasonically nebulized distilled water (UNDW) can induce bronchoconstriction only in asthmatics, but mechanisms of the response are not well known. We recently reported a guinea‐pig model of UNDW‐induced bronchoconstriction (UNDW‐IB) in which UNDW induces bronchoconstriction when UNDW is inhaled 20 min after a challenge with aerosolized ovalbumin (OA) in passively sensitized, anaesthetized and artificially ventilated guinea‐pigs.
To elucidate the role of histamine in the UNDW‐IB, we examined the effects of antihistamines, diphenhydramine hydrochloride (DH) and chlorpheniramine maleate (CP), and measured histamine content in bronchoalveolar lavage fluid (BALF) in the animal model.
DH in doses of 0.1, 1.0 and 10 mg kg−1 and CP in doses of 0.01, 0.1 and 1.0 mg kg−1 administered intravenously 15 min after the OA challenge partially reduced the UNDW‐IB at 1 and 2 min after the UNDW inhalation in a dose‐dependent manner. Histamine content in BALF recovered 10 min after the UNDW inhalation following the OA provocation was significantly increased compared with that after saline inhalation and before the UNDW inhalation following the OA challenge.
Intravenous atropine in a dose of 0.5 mg kg−1 or inhaled disodium cromoglycate in concentrations of 1 and 10 mg ml−1 did not alter the UNDW‐IB.
These results suggest that histamine is involved in part in the UNDW‐IB in our animal model.

British Journal of Pharmacology (1998) 125, 902–908; doi:10.1038/sj.bjp.0702135
Contributions of cysteine 114 of the human D3 dopamine receptor to ligand binding and sensitivity to external oxidizing agents
Authors: Alberts Glen L , Pregenzer Jeffrey F , Bin Im Wha 
Published: January 2005

Cysteine 114 (C114) of the human dopamine D3 receptor is located at the helical face of transmembrane segment III (TMIII) near aspartate 110, a counterion for the amine group of catecholamines. The contributions of C114 to receptor function were investigated here using site‐directed mutagenetis of C114 to serine.
The C114S mutant, as expressed in Sf‐9 cells, bound aminotetralin antagonists (UH‐232 and AJ‐76) and several agonists ((−)3‐PPP, apomorphine, pramipexole and quinpirole) with markedly lower affinities as compared to the wild type D3 receptor, but bound other structurally diverse dopaminergic ligands with only minor changes in affinity. Because an N‐propyl substituent is the only common structural feature among most affected ligands, we propose that the mutation alters ‘a propyl cleft’ on the receptor. The mutation hardly affected quinpirole‐dependent [35S]‐GTPγS binding, suggesting C114 plays a minimal role in receptor‐G‐protein coupling.
N‐Ethylmaleimide(NEM), a sulfhydryl modifying agent, blocked ligand binding to the D3 receptor, but not to the C114S mutant. We infer that C114 is the primary residue on the D3 receptor vulnerable to external oxidizing agents. Dopamine D2long and D42 receptors contain highly homologous TMIII sequences including an equivalent cysteine residue. However, only the D2long receptor, not the D42 receptor, displayed NEM sensitivity similar to that of the D3 receptor.
We conclude that C114 is critical for high affinity interactions between the D3 receptor and ligands containing an N‐propyl substituent, and unlike its counterpart in the D42 receptor, is highly susceptible to external oxidizing agents.

British Journal of Pharmacology (1998) 125, 705–710; doi:10.1038/sj.bjp.0702136
Lipopolysaccharide enhances neurogenic plasma exudation in guinea‐pig airways
Authors: Kuo H ‐P , Hwang K ‐H , Lin H ‐C , Wang C ‐H , Liu C ‐Y , Lu L ‐C 
Published: January 2005

Lipopolysaccharide (LPS) is implicated in many pulmonary and airway inflammatory diseases. Tachykinins released from nerve endings increase vascular permeability. In this study, we have assessed the enhancement by LPS of tachykinin‐mediated plasma exudation in guinea‐pig airways, and examined the role of oxidants as well as leukocyte adherence.
LPS (100 μg kg−1, i.v.) was administered 0–3 h before bilateral electrical stimulation of the cervical vagus nerves in animals anaesthetized with urethane and ventilated. Vagal stimulation increased vascular permeability in the airways. LPS enhanced the vagally‐mediated plasma exudation with the peak effect at 1 h after LPS administration. LPS alone induced no significant plasma exudation. LPS also enhanced exogenous substance P (10−8 mol kg−1, i.v.)‐induced plasma exudation.
The NK‐1 receptor antagonist L‐732,138 abolished vagally‐induced plasma exudation and significantly inhibited the enhancement by LPS. Pretreatment with superoxide dismutase (SOD, 5000 U kg−1, i.p.) did not affect the vagally‐induced plasma exudation, but inhibited the LPS‐enhanced neurogenic plasma leakage. The LPS‐enhanced vagally‐induced plasma exudation was not completely inhibited by either L‐732,138 or SOD pretreatment alone, but was blocked by the combination of both pretreatments.
Neutrophil depletion by cyclophosphamide alone did not influence vagally‐induced plasma exudation, but significantly inhibited the LPS‐enhanced response.
In conclusion, we have demonstrated LPS enhanced neurogenic plasma exudation by augmenting the response to tachykinins, partly through NK‐1 receptors, to directly increase vascular permeability or to enhance leukocyte adhesion‐mediated endothelial cell injury. Tachykinins released from nerve endings may contribute to endotoxin‐related airway inflammatory responses.

British Journal of Pharmacology (1998) 125, 711–716; doi:10.1038/sj.bjp.0702138
Effect of endothelin‐1 (1‐31) on extracellular signal‐regulated kinase and proliferation of human coronary artery smooth muscle cells
Authors: Yoshizumi Masanori , Kim Shokei , Kagami Shoji , Hamaguchi Akinori , Tsuchiya Koichiro , Houchi Hitoshi , Iwao Hiroshi , Kido Hiroshi , Tamaki Toshiaki 
Published: January 2005

We have previously found that human chymase cleaves big endothelins (ETs) at the Tyr31‐Gly32 bond and produces 31‐amino acid ETs (1‐31), without any further degradation products. In this study, we investigated the effect of synthetic ET‐1 (1‐31) on the proliferation of cultured human coronary artery smooth muscle cells (HCASMCs).
ET‐1 (1‐31) increased [3H]‐thymidine incorporation and cell numbers to a similar extent as ET‐1 at 100 nM. This ET‐1 (1‐31)‐induced [3H]‐thymidine uptake was not affected by phosphoramidon, an inhibitor of ET‐converting enzyme. It was, however, inhibited by BQ123, an endothelin ETA receptor antagonist, but not by BQ788, an endothelin ETB receptor antagonist.
By using an in‐gel kinase assay, we demonstrated that ET‐1 (1‐31) activated extracellular signal‐regulated kinase 1/2 (ERK1/2) in a concentration‐dependent manner (100 pM to 1 μM) in HCASMCs. ET‐1 (1‐31)‐induced ERK1/2 activation was inhibited by BQ123, but not by BQ788 and phosphoramidon. Inhibition of protein kinase C (PKC) and ERK kinase also caused a reduction of ET‐1 (1‐31)‐induced ERK1/2 activation, whereas tyrosine kinase inhibition had little effect.
Gel‐mobility shift analysis revealed that the ERK1/2 activation was followed by an increase in transcription factor activator protein‐1 DNA binding activity in HCASMCs.
Our results strongly suggest that ET‐1 (1‐31) itself stimulates HCASMC proliferation probably through endothelin ETA or ETA‐like receptors. The underlining mechanism of cell growth by ET‐1 (1‐31) may be explained in part by PKC‐dependent ERK1/2 activation. Since human chymase has been proposed to play a role in atherosclerosis, ET‐1 (1‐31) may be one of the mediators.

British Journal of Pharmacology (1998) 125, 1019–1027; doi:10.1038/sj.bjp.0702141
Comparative desensitization of the human 5‐HT2A and 5‐HT2C receptors expressed in the human neuroblastoma cell line SH‐SY5Y
Authors: Briddon S.J. , Leslie R.A. , Elliott J.M. 
Published: January 2005

We have used previously characterized clones of the human neuroblastoma cell line, SH‐SY5Y, constitutively expressing either the human 5‐HT2A or 5‐HT2C receptor to compare their desensitization profiles after exposure to 5‐HT.
5‐HT stimulated [3H]‐inositol phosphate ([3H]‐IPx) production at both the 5‐HT2C (pEC50=8.03±0.15) and 5‐HT2A receptors (pEC50=7.15±0.08), with maximal responses occurring after exposure to 1 μM and 10 μM 5‐HT, respectively.
Exposure of cells to maximally effective concentrations of 5‐HT caused time‐ and concentration‐dependent desensitization of [3H]‐IPx formation. The 5‐HT2A response desensitized slower (t1/2=110 min) and with lower sensitivity than that of the 5‐HT2C receptor (t1/2=12.5 min). In each case, desensitization was blocked by co‐administration of a specific receptor antagonist. Following exposure to 10 μM 5‐HT for 2 h, both receptors exhibited extensive desensitization, with subsequent responses to 5‐HT reduced by more than 80%.
5‐HT stimulated Ins(1,4,5)P3 production with a potency similar to that for [3H]‐IPx production at each receptor. In both cases Ins(1,4,5)P3 levels peaked rapidly then returned to basal level within a short time. This peak consistently occurred earlier for the 5‐HT2C receptor (5 s) than for the 5‐HT2A receptor (20 s).
Prior exposure of SH‐SY5Y/5‐HT2C cells to 5‐HT (1 μM/15 min) caused a significant decrease in the 5‐HT‐stimulated peak in Ins(1,4,5)P3 levels whereas no such change occurred in SH‐SY5Y/5‐HT2A cells following exposure to 10 μM 5‐HT for 15 min.
These results indicate that the human 5‐HT2A and 5‐HT2C receptors both exhibit desensitization at the level of inositol phosphate formation when expressed in the same cellular environment, with the 5‐HT2C receptor being more sensitive to 5‐HT‐mediated desensitization than the 5‐HT2A receptor.

British Journal of Pharmacology (1998) 125, 727–734; doi:10.1038/sj.bjp.0702145
Characterization of receptors mediating contraction of the rat isolated small mesenteric artery and aorta to arginine vasopressin and oxytocin
Authors: Stam Wiro B , Van der Graaf Pieter H , Saxena Pramod R 
Published: January 2005

The exact nature of the receptor subtype(s) involved in the action of arg‐vasopressin (AVP) on the rat aorta and small mesenteric artery (SMA) is controversial. Therefore, we have studied the effects of the selective V1A receptor antagonists, OPC 21268 and SR 49059, and the oxytocin (OT) receptor antagonist, atosiban, on the AVP‐ and OT‐induced contractions of the two vessels.
AVP and OT displayed similar intrinsic activities in the rat aorta and SMA, but AVP was ∼130 fold and ∼500 fold more potent than OT, respectively. In the rat aorta, Hill slopes (nH) were similar for OT and AVP. However, in rat SMA, the OT concentration‐effect (E/[A]) curve was significantly steeper than the AVP E/[A] curve (nH,=3.3±0.20, 2.3±0.15; P<0.001).
In the aorta OPC 21268, SR 49059 and atosiban competitively antagonized the AVP and OT E/[A] curves. Except for atosiban and SR 49059 against AVP, competitive antagonism was also observed in the SMA. Atosiban caused concentration‐dependent steepening of the AVP E/[A] curve, whereas SR 49059 decreased the upper asymptote.
Schild analysis yielded affinities indicative of V1A receptor involvement in both vessels: pKB/pA2=9.20–9.48, 7.56–7.71 and 6.19–6.48 for SR 49059, OPC 21268 and atosiban, respectively.
Neither AVP nor OT relaxed U46619 pre‐contracted aorta or SMA in the presence of SR 49059, suggesting no interference of a vasodilatory component.
Despite predominant involvement of V1A receptors in both vessels, the different Hill slopes of AVP and OT E/[A] curves as well as the steepening of the AVP E/[A] curves by atosiban are indicative of receptor heterogeneity in the rat SMA.

British Journal of Pharmacology (1998) 125, 865–873; doi:10.1038/sj.bjp.0702149
Pharmacodynamic interaction between phenytoin and sodium valproate changes seizure thresholds and pattern
Authors: Paschoa O. E. Della , Kruk M. R. , Hamstra R , Voskuyl R. A. , Danhof M 
Published: January 2005

In this study we used cortical stimulation to assess the effects of phenytoin (PHT), sodium valproate (VPA), and their interaction on total motor seizure and on the constituent elements of the seizure.
PHT (40 mg kg−1) was administered as an intravenous bolus infusion to animals receiving either a continuous infusion of VPA or saline. VPA plasma concentration was maintained at levels that produced no detectable anticonvulsant effect.
Analysis of ictal components (eyes closure, jerk, gasp, forelimb, clonus, and hindlimb tonus) and their durations revealed both qualitative and quantitative differences in drug effects.
The anticonvulsant effect is represented by the increase in the duration of the stimulation required to reach a given seizure threshold. PHT significantly increased the duration of the stimulation and of the motor seizure. This increase was greatly enhanced by VPA. In addition, ictal component analysis revealed that the combination of PHT and VPA causes the reduction of a specific seizure component (JERK).
Neither the free fraction of PHT nor the biophase equilibration kinetics changes in the presence of VPA. It is concluded that the synergism may be due to a pharmacodynamic rather than a pharmacokinetic interaction.

British Journal of Pharmacology (1998) 125, 997–1004; doi:10.1038/sj.bjp.0702155
The action of calcium channel blockers on recombinant L‐type calcium channel α1‐subunits
Authors: Morel Nicole , Buryi Vitali , Feron Olivier , Gomez Jean‐Pierre , Christen Marie‐Odile , Godfraind Théophile 
Published: January 2005

CHO cells expressing the α1C‐a subunit (cardiac isoform) and the α1C‐b subunit (vascular isoform) of the voltage‐dependent L‐type Ca2+ channel were used to investigate whether tissue selectivity of Ca2+ channel blockers could be related to different affinities for α1C isoforms.
Inward current evoked by the transfected α1 subunit was recorded by the patch‐clamp technique in the whole‐cell configuration.
Neutral dihydropyridines (nifedipine, nisoldipine, (+)‐PN200‐110) were more potent inhibitors of α1C‐b‐subunit than of α1C‐a‐subunit. This difference was more marked at a holding potential of −100 mV than at −50 mV. SDZ 207‐180 (an ionized dihydropyridine) exhibited the same potency on the two isoforms.
Pinaverium (ionized non‐dihydropyridine derivative) was 2 and 4 fold more potent on α1C‐a than on α1C‐b subunit at Vh of −100 mV and −50 mV, respectively. Effects of verapamil were identical on the two isoforms at both voltages.
[3H]‐(+)‐PN 200‐110 binding experiments showed that neutral dihydropyridines had a higher affinity for the α1C‐b than for the α1C‐a subunit. SDZ 207‐180 had the same affinity for the two isoforms and pinaverium had a higher affinity for the α1C‐a subunit than for the α1C‐b subunit.
These results indicate marked differences among Ca2+ channel blockers in their selectivity for the α1C‐a and α1C‐b subunits of the Ca2+ channel.

British Journal of Pharmacology (1998) 125, 1005–1012; doi:10.1038/sj.bjp.0702162
Effects of chronic application of propranolol on β‐adrenergic signal transduction in heart ventricles from myopathic BIO TO2 and control hamsters
Authors: Witte Klaus , Schnecko Anke , Hauth Daniela , Wirzius Sandra , Lemmer Björn 
Published: January 2005

In human congestive heart failure β‐adrenoceptor antagonists improve exercise tolerance and cardiac contractility. These beneficial effects are thought to reflect an up‐regulation of cardiac β‐adrenoceptors, involving mainly the β1‐subtype. In the present study we evaluated the functional contribution of β‐adrenoceptor subtypes to stimulation of adenylyl cyclase in an animal model of dilated cardiomyopathy, and compared the effects of treatment with propranolol on cardiac β‐adrenergic signal transduction in myopathic and control hamsters.
Cardiomyopathic BIO TO2 hamsters and BIO F1B controls aged 270 days were used. In the treatment study, hamsters received drinking water with or without propranolol 40 mg kg−1 d−1 for 4 weeks prior to sacrifice. Density and subtype distribution of β‐adrenoceptors were determined in radioligand binding studies. Functional contributions of β‐adrenoceptors were evaluated by subtype‐selective stimulation of adenylyl cyclase. Cardiac G‐protein content was determined by immunoblotting.
Compared to BIO F1B controls, myopathic hamsters showed increases in cardiac total β‐ and β2‐adrenoceptor density, Gsα and Giα content. In BIO TO2 ventricles, β1‐adrenoceptors were almost completely uncoupled from adenylyl cyclase stimulation despite an unchanged density. Treatment of hamsters with propranolol resulted in increased density of β1‐adrenoceptors in both strains, but had no effect on their functional efficacy. Moreover, β2‐adrenergic stimulation of adenylyl cyclase was even reduced in propranolol‐treated animals, which could not be explained by changes in cardiac G‐protein content.
Cardiomyopathic BIO TO2 hamsters showed functional uncoupling of cardiac β1‐adrenoceptors, which could not be normalized by propranolol and, therefore, is unlikely to be solely due to agonist‐dependent desensitization. The paradoxical reduction in β2‐adrenergic efficiency in propranolol‐treated myopathic and control hamsters deserves further investigation.

British Journal of Pharmacology (1998) 125, 1033–1041; doi:10.1038/sj.bjp.0702165
Characterization of protein serine/threonine phosphatase activities in human lung mast cells and basophils
Authors: Peirce Matthew J. , Munday Michael R. , Peachell Peter T. 
Published: January 2005

The serine/threonine protein phosphatase (PP) inhibitors, okadaic acid and calyculin, attenuated the IgE‐mediated release of histamine from human lung mast cells (HLMC) and basophils in a dose‐dependent manner whereas an alternative PP inhibitor, microcystin, was ineffective. Calyculin was more potent than okadaic acid in both cell types. The concentration required to inhibit by 50% (IC50) the release of histamine was 15 (HLMC) and 50 nM(basophils) for calyculin and 200 (HLMC) and 300 nM(basophils) for okadaic acid.Lysates of purified HLMC and basophils dephosphorylated radiolabelled glycogen phosphorylase, a substrate for both PP1 and PP2A. The PP activity in lysates of both cell types was inhibited in a dose‐dependent fashion by the PP inhibitors with the following rank order of activity, calyculin (approximate IC50; 0.02–0.1 nM)microcystin (0.1 nM)>okadaic acid (70 nM).The PP1‐selective inhibitor, inhibitor‐2 (I‐2), attenuated the dephosphorylation of glycogen phosphorylase in lysates of both HLMC and basophils. I‐2 (20 nM) inhibited the glycogen phosphorylase PP activity by 71±3% and 49±13% in HLMC and basophil extracts, respectively. There were, approximately, 6 fold greater levels of I‐2‐sensitive activity in HLMC than in basophils. Qualitatively similar results were obtained with an alternative PP1‐selective inhibitor, inhibitor‐1 (I‐1).Lysates derived from HLMC and basophils dephosphorylated radiolabelled casein which is a PP2A‐restricted substrate. HLMC lysates contained, approximately, 2.5 fold higher levels of casein PP activity than basophil lysates.These data indicate that HLMC and basophils both contain PP1 and PP2A. The data suggest that, on a per cell basis, HLMC have higher levels of both PP1 and PP2A. Moreover, the ratio of PP1 to PP2A is higher in HLMC than in basophils.British Journal of Pharmacology(1998)125, 1095–1101; doi:10.1038/sj.bjp.0702169
LU 73068, a new non‐NMDA and glycine/NMDA receptor antagonist: pharmacological characterization and comparison with NBQX and L‐701,324 in the kindling model of epilepsy
Authors: Potschka H , Löscher W , Wlaź P , Behl B , Hofmann H P , Treiber H‐J , Szabo L 
Published: January 2005

The aim of this study was to assess whether a drug which combines an antagonistic action at both NMDA and non‐NMDA receptors offers advantages for treatment of epileptic seizures compared to drugs which antagonize only one of these ionotropic glutamate receptors.
The novel glutamate receptor antagonist LU 73068 (4,5‐dihydro‐1‐methyl‐4‐oxo‐7‐trifluoromethyl‐imidazo[1,2a]quinoxaline‐2‐carbonic acid) binds with high affinity to both the glycine site of the NMDA receptor (Ki 185 nm) and to the AMPA receptor (Ki 158 nm). Furthermore, binding experiments with recombinant kainate receptor subunits showed that LU 73068 binds to several of these subunits, particularly to rGluR7 (Ki 104 nm) and rGluR5 (Ki 271 nm). In comparison, the prototype non‐NMDA receptor antagonist NBQX (2,3‐dihydroxy‐6‐nitro‐7‐sulphamoyl‐benzo[f]quinoxaline) binds with high affinity to AMPA receptors only.
Both NBQX and LU 73068 were about equieffective after i.p. injection in mice to block lethal convulsions induced by AMPA or NMDA.
In the rat amygdala kindling model of temporal lobe epilepsy, LU 73068 dose‐dependently increased the focal seizure threshold (afterdischarge threshold, ADT). When rats were stimulated with a current 20% above the individual control ADT, LU 73068 completely blocked seizures with an ED50 of 4.9 mg kg−1.
Up to 20 mg kg−1, only moderate adverse effects, e.g. slight ataxia, were observed.
NBQX, 10 mg kg−1, and the glycine/NMDA site antagonist L‐701,324 (7‐chloro‐4‐hydroxy‐3‐(3‐phenoxy)phenyl‐quinoline‐2(1H)one), 2.5 or 5 mg kg−1, exerted no anticonvulsant effects in kindled rats when administered alone, but combined treatment with both drugs resulted in a significant ADT increase.
The data indicate that combination of glycine/NMDA and non‐NMDA receptor antagonism in a single drug is an effective means of developing a potent and effective anticonvulsant agent.

British Journal of Pharmacology (1998) 125, 1258–1266; doi:10.1038/sj.bjp.0702172