bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional and desensitizing effects of the novel synthetic vanilloid‐like agent 12‐phenylacetate 13‐acetate 20‐homovanillate (PPAHV) in the perfused rat hindlimb
Authors: Griffiths Cory D , Vincent Michelle A , Szallasi Arpad , Colquhoun Eric Q , Geraghty Dominic P 
Published: January 2005

In the present study, the effects of the novel vanilloid agonist, 12‐phenylacetate 13‐acetate 20‐homovanillate (PPAHV), on oxygen consumption (VO2) and vascular resistance (perfusion pressure, PP) were investigated in the constant flow, perfused rat hindlimb. The acute desensitizing properties of this novel synthetic agent were also examined.
Maximum stimulation of VO2 was produced by 0.2 μM PPAHV (ΔVO2, 0.83±0.06 μmol g−1 h−1) and was accompanied by mild vasoconstriction (increase in PP; 8.0±1.1 mmHg). The highest concentration of PPAHV tested (2 μM) caused inhibition of VO2 (ΔVO2, −2.73±0.51 μmol g−1 h−1) and strong vasoconstriction (ΔPP, 42.0±1.2 mmHg).
Capsazepine (10 μM) caused a parallel shift to the right of both VO2 and PP concentration‐response curves for PPAHV (pKb=5.00), indicative of competitive binding to vanilloid receptors.
The stimulation of VO2 produced by 0.2 μM PPAHV decreased, but was not completely abolished, after repeated infusion of PPAHV (change in VO2, first infusion, 0.66±0.18 μmol g−1 h−1; sixth infusion, 0.29±0.08 μmol g−1 h−1, P<0.05), an acute tachyphylactic response not previously seen with the repeated infusion of other vanilloid analogues. Conversely, the PP response to repeated PPAHV infusion increased (ΔPP, first infusion, 5.8±0.7 mmHg; sixth infusion, 9.0±0.6 mmHg, P<0.05).
In conclusion, PPAHV produces vasoconstriction and a biphasic effect on VO2 in the perfused rat hindlimb very similar to that induced by naturally occurring vanilloids. Both effects are blocked by the competitive antagonist capsazepine. Since, the metabolic response to low concentrations of PPAHV (stimulation of VO2) undergoes tachyphylaxis, the present data suggest that PPAHV desensitizes putative vanilloid receptors in the hindlimb.

British Journal of Pharmacology (2000) 131, 1408–1412; doi:10.1038/sj.bjp.0703702
21‐NO‐prednisolone is a novel nitric oxide‐releasing derivative of prednisolone with enhanced anti‐inflammatory properties
Authors: Paul‐Clark Mark , Del Soldato Piero , Fiorucci Stefano , Flower Roderick J , Perretti Mauro 
Published: January 2005

Anti‐inflammatory effects of a novel derivative of the glucocorticoid prednisolone were investigated. NCX‐1015 (prednisolone 21‐[(4′‐nitrooxymethyl)benzoate]) incubation in human platelet‐rich plasma produced a time (0–60 min) and concentration (3–300 μM) dependent release of nitrite, that was mirrored by accumulation of cyclic guanosine monophosphate in the human platelets. Intraperitoneal injection of NCX‐1015 to mice (up to 27.7 μmol kg−1) produced nitrite accumulation in the peritoneal cavity maximal at 60 min.
NCX‐1015 dose‐dependently induced the steroid sensitive cell surface marker CD163 in human peripheral blood mononuclear cells (PBMCs). NCX‐1015 was more potent than prednisolone in inducing CD163. Similarly, lipopolysaccharide induced interleukin‐1β release from these cells was inhibited by NCX‐1015 with higher potency than prednisolone.
In the zymosan peritonitis model, NCX‐1015 was more active than prednisolone in suppressing neutrophil extravasation (ED50 of 5.5 and 25.8 μmol kg−1, respectively), nitrite accumulation (ED50 of 1.38 and 22.2 μmol kg−1, respectively) and release of the chemokine KC (ED50 of 5.5 and 27.7 μmol kg−1, respectively) as determined at the 4 h time‐point. No differences were measured for the levels of interleukin‐1β or prostaglandin E2. NCX‐1015 administered orally was also found to be equally active. Co‐administration of the nitric oxide donors NOC‐18 ((z)‐1‐[(2‐aminoethyl)‐N‐(2‐aminoethyl)amino] diazen‐1‐ium‐1, 2‐diolate; 7.9 μmol kg−1) or sodium nitroprusside (13.8 μmol kg−1) with prednisolone resulted in an additive anti‐migratory action.
In a chronic model of granulomatous tissue inflammation, administration of NCX‐1015 (13.9 μmol kg−1) from day 1 (i.e. after induction of inflammation) was more effective than prednisolone in reducing the granuloma dry weight, and this was associated to a lower anti‐angiogenic effect.
In conclusion we show that NCX‐1015 is more potent than prednisolone in controlling several, though not all, parameters of acute and chronic inflammation, and propose that this effect may be due to a co‐operation between the steroid moiety and nitric oxide or related species released in biological fluids. Whereas this aspect needs to be further clarified, we propose NCX‐1015 as the first member of a novel class of anti‐inflammatory compounds, the nitro‐steroids.

British Journal of Pharmacology (2000) 131, 1345–1354; doi:10.1038/sj.bjp.0703704
Endothelial dysfunction in atherosclerotic mice: improved relaxation by combined supplementation with L‐arginine‐tetrahydrobiopterin and enhanced vasoconstriction by endothelin
Authors: Jiang Jiahua , Valen Guro , Tokuno Shinichi , Thorén Peter , Pernow John 
Published: January 2005

Mice lacking the apolipoprotein E and low density lipoprotein receptor genes (E°xLDLR°) develop atherosclerosis and endothelial dysfunction. The aim of this study was to characterize the roles of L‐arginine and tetrahydrobiopterin (BH4) for endothelium‐dependent relaxation and the changes in the vasoconstrictor response to endothelin‐1 (ET‐1) in thoracic aortic rings of E°xLDLR° mice.
Histological examination revealed severe atherosclerosis of the thoracic aorta of E°xLDLR° mice. Relaxations induced by acetylcholine (Ach), but not that to sodium nitroprusside, were significantly impaired in E°xLDLR° mice compared to control mice indicating attenuated endothelium‐dependent relaxations.
Preincubation with the nitric oxide (NO) substrate L‐arginine did not affect, whereas the co‐factor for NO synthase, BH4, slightly improved the relaxations induced by Ach. Combined preincubation with L‐arginine and BH4 induced a pronounced enhancement of Ach‐induced relaxations in E°xLDLR° mice. The relaxations induced by Ach in E°xLDLR° mice in the presence of L‐arginine and BH4 were not different from those observed in control mice.
Preincubation with superoxide dismutase did not affect Ach‐induced relaxations in aorta from E°xLDLR° mice.
The contractile response to ET‐1 was enhanced in E°xLDLR° mouse aorta. The contractions were abolished by the ETA receptor antagonist LU 135252. The ETB receptor agonist sarafotoxin 6c did not induce contractions or relaxations.
It is concluded that endothelial dysfunction of E°xLDLR° mouse aorta is reversed by combined administration of L‐arginine and BH4. In addition, the ETA receptor‐mediated vasoconstriction by ET‐1 is enhanced in E°xLDLR° mice.

British Journal of Pharmacology (2000) 131, 1255–1261; doi:10.1038/sj.bjp.0703705
Effects of diclofenac, aceclofenac and meloxicam on the metabolism of proteoglycans and hyaluronan in osteoarthritic human cartilage
Authors: Blot Laurent , Marcelis Annette , Devogelaer Jean‐Pierre , Manicourt Daniel‐Henri 
Published: January 2005

Since nonsteroidal anti‐inflammatory drugs (NSAIDs) may impair the ability of the chondrocyte to repair its damaged extracellular matrix, we explored the changes in the metabolism of newly synthesized proteoglycan and hyaluronan (HA) molecules produced by aceclofenac, diclofenac and meloxicam in human osteoarthritic (OA) cartilage.
Explants were sampled from the medial femoral condyle and were classified by use of the Mankin's histological‐histochemical grading system. Cartilage specimens exhibited moderate (M) OA in 20 subjects and had severe (S) OA in 20.
Cartilage explants were pulsed with [‐3H]‐glucosamine and chased in the absence or in the presence of 0.3–3 μg ml−1 of either aceclofenac, diclofenac or meloxicam. After papain digestion, the labelled chondroitin sulphate ([‐3H]‐proteoglycans) and [‐3H]‐HA molecules present in the tissue and media were purified by anion‐exchange chromatography.
In cartilage with MOA and SOA, the metabolic balance of proteoglycan and HA was unaffected by diclofenac. In contrast, and in a dose‐dependent manner, aceclofenac and meloxicam both increased the synthesis of proteoglycans and HA in explants with MOA and SOA; these two NSAIDs also reduced significantly the net loss of [‐3H]‐proteoglycans and [‐3H]‐HA molecules from cartilage explants.
The data obtained in short‐term in vitro cultures indicate that, at the concentrations found in synovial fluid, aceclofenac and meloxicam may exert a favourable effect on the overall metabolism of proteoglycans and HA in cartilage with MOA and SOA.

British Journal of Pharmacology (2000) 131, 1413–1421; doi:10.1038/sj.bjp.0703710
Distinct pharmacology of rat and human histamine H3 receptors: role of two amino acids in the third transmembrane domain
Authors: Ligneau X , Morisset S , Tardivel‐Lacombe J , Gbahou F , Ganellin C R , Stark H , Schunack W , Schwartz J ‐C , Arrang J ‐M 
Published: January 2005

Starting from the sequence of the human histamine H3 receptor (hH3R) cDNA, we have cloned the corresponding rat cDNA. Whereas the two deduced proteins show 93.5% overall homology and differ only by five amino acid residues at the level of the transmembrane domains (TMs), some ligands displayed distinct affinities. Thioperamide and ciproxifan were about 10 fold more potent at the rat than at the human receptor, whereas FUB 349 displayed a reverse preference. Histamine, (R)α‐methylhistamine, proxyfan or clobenpropit were nearly equipotent at H3 receptors of both species. The inverse discrimination patterns of ciproxifan and FUB 349 were partially changed by mutation of one amino acid (V122A), and fully abolished by mutation of two amino acids (A119T and V122A), in TM3 of the rH3R located in the vicinity of Asp114 purported to salt‐link the ammonium group of histamine. Therefore, these two residues appear to be responsible for the distinct pharmacology of the H3R in the two species.British Journal of Pharmacology (2000) 131, 1247–1250; doi:10.1038/sj.bjp.0703712
Selective mGluR5 antagonists MPEP and SIB‐1893 decrease NMDA or glutamate‐mediated neuronal toxicity through actions that reflect NMDA receptor antagonism
Authors: O'Leary Deirdre M , Movsesyan Vilen , Vicini Stefano , Faden Alan I 
Published: January 2005

The metabotropic glutamate receptors (mGluRs) are a family of G‐protein linked receptors that can be divided into three groups (group I, II and III). A number of studies have implicated group I mGluR activation in acute neuronal injury, but until recently it was not possible to pharmacologically differentiate the roles of the two individual subunits (mGluR1 and mGluR5) in this group.
We investigated the role of mGluR5 in acute NMDA and glutamate mediated neurodegeneration in cultured rat cortical cells using the mGluR5 antagonists MPEP and SIB‐1893, and found that they provide significant protection at concentrations of 20 or 200 μM.
These compounds act as effective mGluR5 antagonists in our cell culture system, as indicated by the ability of SIB‐1893 to prevent phosphoinositol hydrolysis induced by the specific mGluR5 agonist, (RS)‐2‐chloro‐5‐hydroxyphenylglycine (CHPG).
However, they also significantly reduce NMDA evoked current recorded from whole cells voltage clamped at −60 mV, and significantly decrease the duration of opening of NMDA channels recorded in the outside out patch configuration.
This suggests that although MPEP and SIB‐1893 are effective mGluR5 antagonists, they also act as noncompetitive NMDA receptor antagonists. Therefore, the neuroprotective effects of these compounds are most likely mediated through their NMDA receptor antagonist action, and caution should be exercised when drawing conclusions about the roles of mGluR5 based on their use.

British Journal of Pharmacology (2000) 131, 1429–1437; doi:10.1038/sj.bjp.0703715
Mechanism of action of the hypnotic zolpidem in vivo
Authors: Crestani Florence , Martin James R , Möhler Hanns , Rudolph Uwe 
Published: January 2005

Zolpidem is a widely used hypnotic agent acting at the GABAA receptor benzodiazepine site. On recombinant receptors, zolpidem displays a high affinity to α1‐GABAA receptors, an intermediate affinity to α2‐ and α3‐GABAA receptors and fails to bind to α5‐GABAA receptors. However, it is not known which receptor subtype is essential for mediating the sedative‐hypnotic action in vivo. Studying α1(H101R) mice, which possess zolpidem‐insensitive α1‐GABAA receptors, we show that the sedative action of zolpidem is exclusively mediated by α1‐GABAA receptors. Similarly, the activity of zolpidem against pentylenetetrazole‐induced tonic convulsions is also completely mediated by α1‐GABAA receptors. These results establish that the sedative‐hypnotic and anticonvulsant activities of zolpidem are due to its action on α1‐GABAA receptors and not on α2‐ or α3‐GABAA receptors.British Journal of Pharmacology (2000) 131, 1251–1254; doi:10.1038/sj.bjp.0703717
The role of M2‐muscarinic receptors in mediating contraction of the pig urinary bladder in vitro
Authors: Yamanishi Tomonori , Chapple Christopher R , Yasuda Kosaku , Chess‐Williams Russell 
Published: January 2005

In urinary bladder, M2‐muscarinic receptors predominate, but it is the smaller population of M3‐receptors which mediate detrusor contraction. This study examines the M2 : M3 ratio and the role of M2‐receptors in contraction of pig urinary bladder.
Competition experiments with [3H]‐QNB determined the ratio of M2 : M3. In functional studies, affinity values (pKB) for 4‐DAMP, darifenacin and methoctramine were calculated. Similar experiments were performed on tissues following selective M3‐inactivation (incubation with 40 nM 4‐DAMP mustard in the presence of 1 μM methoctramine to protect M2‐receptors), precontraction with 50 mM KCl and relaxation with isoprenaline (30 μM) or forskolin (1 μM).
In competition binding, displacement of [3H]‐QNB by 4‐DAMP, darifenacin and methoctramine best fitted a two‐site model suggesting a predominant (70–80%) population of M2‐receptors.
On normal detrusor in vitro, 4‐DAMP and methoctramine caused surmountable antagonism of responses to carbachol with pKB values of 9.37±0.07 and 6.05±0.05 respectively. Darifenacin caused unsurmountable antagonism, the apparent pKB value being 8.61±0.10.
In tissues where the M3‐receptors had been inactivated and cyclic AMP levels elevated, 4‐DAMP and darifenacin were less potent, with apparent pKB values of 8.72±0.08 and 6.74±0.07. In contrast, methoctramine was more potent, the apparent pKB value increasing significantly to 6.86±0.06.
These data suggest that the pig bladder possesses a similar muscarinic receptor population to the human bladder and that the M3‐receptor subtype mediates contraction of the normal detrusor muscle. However an involvement of M2‐receptors in contraction can be observed following pharmacological manipulation of the receptor population.

British Journal of Pharmacology (2000) 131, 1482–1488; doi:10.1038/sj.bjp.0703719
In vivo modulation of vagal‐identified dorsal medullary neurones by activation of different 5‐Hydroxytryptamine2 receptors in rats
Authors: Sévoz‐Couche Caroline , Spyer K Michael , Jordan David 
Published: January 2005

In in vivo experiments, DOI (a 5‐HT2 receptor agonist), MK‐212 (a 5‐HT2C receptor agonist), and BW‐723C86 (a 5‐HT2B receptor agonist) were applied by ionophoresis to neurones in the rat nucleus tractus solitarius (NTS) receiving vagal afferent input.
The majority of the putative ‘monosynaptically’ vagal activated cells were inhibited by both MK‐212 (4/6) and DOI (2/4), but unaffected by BW‐723C86 (12/14). In contrast, ‘polysynaptically’ activated NTS cells were excited by both BW‐723C86 (13/19) and DOI (9/10). Inactive ‘intermediate’ cells were inhibited by BW‐723C86 (9/12), MK‐212 (5/6) and DOI (3/4), whilst active cells of this group were excited by BW‐723C86 (7/13) and DOI (5/5).
The selective 5‐HT2B receptor antagonist LY‐202715 significantly reduced the excitatory actions of BW‐723C86 on ‘intermediate’ and ‘polysynaptic’ cells (13/13), but not the inhibitory effects observed on inactive Group 2 cells (n=5) whereas the selective 5‐HT2C receptor antagonist RS‐102221 reversed the inhibitory effects of MK‐212 and DOI on ‘monosynaptic and ‘intermediate’ neurones.
Cardio‐pulmonary afferent stimulation inhibited two of four putative ‘monosynaptically’ activated calls and all four inactive intermediate cells. These were also inhibited by DOI and MK‐212. In contrast, cardio‐pulmonary afferents excited all five active intermediate cells and all six putative ‘polysynaptically’ activated NTS cells, while all were also previously excited by BW‐723C86 and/or DOI.
In conclusion, these data demonstrate that neurones in the NTS are affected differently by 5‐HT2 receptor ligands, in regard of their vagal postsynaptic location, the type of cardio‐pulmonary afferent they receive and the different 5‐HT2 receptors activated.

British Journal of Pharmacology (2000) 131, 1445–1453; doi:10.1038/sj.bjp.0703722
The role of the Ca2+ regulatory sites of skeletal troponin C in modulating muscle fibre reactivity to the Ca2+ sensitizer bepridil
Authors: Kischel P , Bastide B , Potter J D , Mounier Y 
Published: January 2005

The Ca2+‐sensor protein troponin C (TnC) exerts a key role in the regulation of muscle contraction, and constitutes a target for Ca2+ sensitizer compounds, such as bepridil, known to increase its apparent Ca2+ affinity. Moreover, bepridil has been reported to exert a differential effect in slow and fast skeletal muscle fibres, which express the slow/cardiac and fast TnC isoform, respectively.
The role of the TnC isoform in establishing the differential effect of bepridil was assessed in slow soleus and fast tibialis rat skinned fibres, by extraction of endogenous TnC and consecutive reconstitution with either slow or fast recombinant TnC. A mutant (VG2), lacking the regulatory site II, was also used to distinguish the role of each regulatory site.
Fast tibialis fibres reconstituted with cardiac TnC exhibited a typical slow bepridil reactivity, while slow soleus fibres reincorporated with fast TnC displayed a typically fast reactivity to bepridil. These results indicated that the differential effect of bepridil in slow and fast fibres is related to the TnC isoform predominantly expressed in a fibre.
Experiments with the VG2 mutant demonstrated that BPD can achieve an increase in the Ca2+ affinity in the absence of a functional site II. Thus, site I was necessary for the BPD effect to be independent of the Ca2+ concentration. Moreover, the amplitude of the reinforcement in the Ca2+ affinity, induced by the binding of bepridil to the TnC molecule, is dependent on the number of functional regulatory sites, the larger affinity reinforcement being detected when only one regulatory site (either site I or II) is functional.

British Journal of Pharmacology (2000) 131, 1496–1502; doi:10.1038/sj.bjp.0703727
Nifedipine suppresses neointimal thickening by its inhibitory effect on vascular smooth muscle cell growth via a MEK‐ERK pathway coupling with Pyk2
Authors: Hirata Akihiko , Igarashi Masahiko , Yamaguchi Hiroshi , Suwabe Akira , Daimon Makoto , Kato Takeo , Tominaga Makoto 
Published: January 2005

The aim of this study was to determine whether nifedipine could suppress an atherogenic process such as balloon‐injured intimal thickening in vivo and the proliferation of vascular smooth muscle cells (VSMC) in vitro.
First, we examined the in vivo effect of nifedipine to determine whether it could suppress intimal thickening induced by balloon catheterization. Sprague‐Dawley (SD) rats were divided into three groups (L, nifedipine 0.3 mg kg−1 day−1; H, nifedipine 3 mg kg−1 day−1; C, no nifedipine), and Alzet® osmotic pumps were implanted in their backs for continuous administration. The neointimal layers were completely occupied by proliferated VSMC, and the area ratios of neointima/media treated with nifedipine significantly decreased dose‐dependently compared to those of the control. Neither blood pressure nor lipid levels changed among the three groups.
We next evaluated the in vitro effect of nifedipine on the proliferation of cultured rat VSMC. Nifedipine decreased the values of [3H]‐thymidine incorporation and total cellular protein content as well as the levels of phosphorylated extracellular signal‐regulated protein kinase (ERK) 1/2, mitogen‐activated protein kinase kinase (MEK) 1/2, and even the phosphorylation of Pyk2, in dose‐dependent fashions. In addition, nifedipine suppressed the levels of proliferative cell nuclear antigen (PCNA) dose‐dependently in both VSMC and balloon‐injured thoracic aortae.
These results indicate that nifedipine has an inhibitory effect on intimal thickening by attenuating intimal VSMC proliferation, suggesting that nifedipine could be effective for preventing the progression of atherosclerotic plaque as in restenosis after angioplasty.

British Journal of Pharmacology (2000) 131, 1521–1530; doi:10.1038/sj.bjp.0703730
Collar‐induced elevation of mRNA and functional activity of 5‐HT1B receptor in the rabbit carotid artery
Authors: Geerts Inge S , De Meyer Guido R Y , Bult Hidde 
Published: January 2005

Hypersensitivity to serotonin (5‐HT) develops in rabbit collared carotid arteries. Previous data demonstrated the involvement of 5‐HT1‐like receptors which are not active in normal carotid arteries. This study investigated the interaction in the rabbit carotid artery between 5‐HT and a moderate tone as this can uncover functional 5‐HT1‐like receptors. Furthermore, the expression of messenger RNA (mRNA) and protein of 5‐HT1B, 5‐HT1D and 5‐HT2A receptors was addressed.
Silicone collars were placed around the carotid arteries of male New Zealand White rabbits for 1 week. Rings from inside (=collar) and outside (=sham) the collar were either mounted in isolated organ baths for isometric force measurements or frozen in liquid nitrogen to isolate total RNA or proteins which were subsequently analysed by respectively reverse transcriptase‐polymerase chain reaction and Western blot analysis.
In sham and collared rings concentration‐response curves (CRC's) to 5‐HT were monophasic. Only in collared segments the presence of a 5‐HT2A antagonist (spiperone or ketanserin, 0.1 μM) revealed a biphasic CRC which was even more pronounced when a moderate tone was induced by KCl pointing to functional 5‐HT1‐like receptors.
The rabbit carotid artery constitutively expressed 5‐HT1B and 5‐HT2A mRNA, not 5‐HT1D mRNA. Manipulation of the carotid artery increased the 5‐HT1B mRNA level. Collar placement raised it even further. The 5‐HT2A mRNA level remained unchanged. All the anti‐5‐HT receptor antibodies tested resulted in variable, non specific patterns with multiple bands.
In conclusion, collar placement elevates mRNA expression and activity of the 5‐HT1B receptor in the rabbit carotid artery.

British Journal of Pharmacology (2000) 131, 1723–1731; doi:10.1038/sj.bjp.0703732