bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contrasting effects of carbachol, McN‐A‐343 and AHR‐602 on Ca2+‐mobilization and Ca2+‐influx pathways in taenia caeci
Authors: Hishinuma Shigeru , Hongo Ikuko , Matsumoto Yukio , Narita Fumihiro , Kurokawa Masanori 
Published: January 2005

We compared the binding profiles and contractile mechanisms of putative muscarinic M1 agonists McN‐A‐343 and AHR‐602 with those of carbachol in smooth muscle of guinea‐pig taenia caeci.
McN‐A‐343 and AHR‐602, as well as carbachol, completely displaced the atropine‐sensitive binding of [3H]‐quinuclidinyl benzilate to muscarinic receptors present in the membrane preparation. The potency order for the affinity of these agents for muscarinic receptors was carbachol>McN‐A‐343>4AHR‐602.
In the presence of 2.2 mM extracellular Ca2+, McN‐A‐343 and AHR‐602 induced contraction corresponding to 79 and 85%, respectively, of the maximal contraction to 0.1 mM carbachol. Contractions induced by these agents were mediated via activation of the muscarinic receptor subtype that had a high affinity for 4‐DAMP (M3 selective) but a low affinity for pirenzepine (M1 selective) and AF‐DX 116 (M2 selective). These contractions were inhibited by an L‐type Ca2+ channel blocker, verapamil.
In Ca2+‐free solution containing 2 mM EGTA, carbachol elicited a transient contraction whereas no contraction was observed in response to McN‐A‐343 and AHR‐602. Application of McN‐A‐343 or AHR‐602 inhibited the carbachol‐induced contraction in Ca2+‐free solution, and this inhibition was surmounted by a higher concentration of carbachol.
The EC50 value for carbachol‐induced contraction in the presence of extracellular Ca2+ was approximately 175 times lower than that in the absence of Ca2+. After treatment with propylbenzilylcholine mustard, carbachol induced contraction only in the presence of extracellular Ca2+.
The results suggest that in the taenia caeci there is a greater receptor reserve for muscarinic M3 receptor‐mediated Ca2+ influx than for M3 mediated Ca2+ release. The compounds McN‐A‐343 and AHR‐602 are agonists of the Ca2+ influx pathway, but do not appear to stimulate the Ca2+ release pathway.

British Journal of Pharmacology (1997) 122, 985–992; doi:10.1038/sj.bjp.0701467
Effect of lacidipine on cholesterol esterification: in vivo and in vitro studies
Authors: Bernini F. , Canavesi M. , Bernardini E. , Scurati N. , Bellosta S. , Fumagalli R. 
Published: January 2005

Cholesterol esterification and accumulation in the arterial wall is a hallmark of atherogenesis. Several preclinical studies suggest that calcium antagonists may exert antiatherosclerotic activity by directly affecting atherogenesis in the arterial wall. We investigated the effect of the second generation dihydropyridine calcium antagonist lacidipine on cholesterol metabolism in vivo in the aortic arch of cholesterol fed rabbits, and in vitro in mouse cultured peritoneal macrophages.
Treatment of cholesterol‐fed rabbits with 1, 3 and 10 mg kg−1 day−1 of lacidipine for two months reduced, in a dose‐dependent manner, cholesterol esterification in the aortic arch: 24±6, 30±12, and 41±8% inhibition, respectively (P<0.001 vs HC control). Concomitantly, drug treatment reduced total cholesterol content of the vessel wall. Lacidipine 3 and 10 mg kg−1 day−1 reduced cholesterolaemia (∼20%); no effect was observed at the lowest dose used (1 mg kg−1 day−1). These results suggest that the action of lacidipine on cholesterol esterification in the arterial wall involves, at least in part, a direct effect on cellular cholesterol metabolism. Inhibition of cholesterol esterification in the arterial wall was observed also in a reference group of animals treated with the specific ACAT inhibitor CI‐976.
To evaluate the action of lacidipine on intracellular cholesterol metabolism we performed in vitro experiments with murine macrophages, the main cell type that accumulates cholesterol in the arterial wall. Lacidipine almost completely inhibited cholesterol esterification in cholesterol loaded macrophages in culture. The effect was observed independently of esterification stimuli and in cell free homogenates. The drug modified intracellular cholesterol distribution, doubling the free‐ to esterified sterol ratio, but did not influence the cellular rate of cholesteryl ester hydrolysis in the cell. All together these results indicate an inhibitory effect of lacidipine on cholesterol esterification catalyzed by the enzyme ACAT in murine macrophages.
We concluded that lacidipine influences cellular cholesterol metabolism. This effect may contribute to the potential antiatherosclerotic activity of this drug.

British Journal of Pharmacology (1997) 122, 1209–1215; doi:10.1038/sj.bjp.0701469
Morphological heterogeneity with normal expression but altered function of G proteins in porcine cultured regenerated coronary endothelial cells
Authors: Borg‐Capra Catherine , Fournet‐Bourguignon Marie‐Pierre , Janiak Philip , Villeneuve Nicole , Bidouard Jean‐Pierre , Vilaine Jean‐Paul , Vanhoutte Paul M. 
Published: January 2005

Experiments were designed to investigate whether the pertussis toxin‐dependent endothelial dysfunction following balloon injury is due to a reduced expression or an insufficient function of G‐proteins.
Endothelium‐dependent responses of porcine coronary arteries were examined in vitro by use of conventional organ chambers. Morphological analysis was performed by isolating and culturing the endothelial cells from these arteries. The expression of Gi‐proteins in regenerated endothelial cells was measured by Western blots and immunolabelling. The function of G‐proteins was assessed by measuring the GTPase activity of cultured endothelial cells.
Eight days following denudation, endothelial regrowth was confirmed by histological examination and by demonstrating the presence of endothelium‐dependent relaxations to bradykinin and 5‐hydroxytryptamine (5‐HT). In primary culture, the regenerated endothelial cells displayed a ‘cobblestone’ pattern as seen with native endothelial cells.
Twenty eight days after denudation, the endothelium‐dependent relaxations induced by 5‐HT were impaired, but those to bradykinin were maintained. However, the latter were reduced when endothelium‐dependent hyperpolarization was prevented.
Twenty eight days after denudation, multinucleated giant cells were present in the regenerated but not in the native cultured endothelial cell populations. These regenerated endothelial cells incorporated less tritiated thymidine than native endothelial cells.
The intensities of the bands on the immunoblot of the regenerated endothelial cells, when several antibodies against Giα1/α2/α3 were used, were the same as those obtained in native endothelial cells. The immunolabelling with the same antibodies was similar between the giant cells and the regenerated endothelial cells of normal size. The hydrolysis of GTP was lower in regenerated than in native endothelial cell membranes.
In conclusion, endothelium‐dependent relaxations mediated by Gi‐proteins are impaired in balloon denuded coronary arteries. This dysfunction following regeneration cannot be explained by a reduced expression of Gi proteins but rather reflects an abnormal function of the G‐proteins in the regenerated endothelium.

British Journal of Pharmacology (1997) 122, 999–1008; doi:10.1038/sj.bjp.0701475
Cardiac inotropes inhibit the oedema caused by nifedipine in rabbit skin
Authors: Taherzadeh Morteza , Warren John B. 
Published: January 2005

We have shown previously that exposing the rat or rabbit microcirculation to nifedipine increases the permeability of the post‐capillary venule, the segment of microcirculation that is known to control inflammatory oedema.
In the present study modulation by the inotropes isoprenaline, dopexamine and dobutamine of nifedipine‐induced oedema was examined in the rabbit skin microcirculation by measuring the localised leakage of 125I‐radiolabelled albumin after the i.d. injection of agents.
Coinjection of isoprenaline (10−11 moles per site), dopexamine (10−10 moles per site) or dobutamine (10−10 moles per site) suppressed significantly (P<0.05) the oedema response to nifedipine (10−7.2 moles per site) in the rabbit dorsal skin microcirculation.
To confirm the oedema suppresser effect of the inotropes, dopexamine or dobutamine were also coinjected with histamine 10−8 +PGE2 10−10 moles per site, or bradykinin 10−10+PGE2 10−10 moles per site. Both inotropes at 10−10 moles per site reduced significantly (P<0.05) the leakage of albumin caused by bradykinin+PGE2 and histamine+PGE2.
When measured by laser Doppler, basal local skin blood flow increased at 30 min by 57±14% with nifedipine 10−7.2 moles per site and 15±11% with isoprenaline 10−11 moles per site. Isoprenaline did not suppress the blood flow response to nifedipine, the response to coinjection being 68±11%.
Oedema caused by nifedipine can be suppressed by low concentrations of β‐adrenergic agonists that do not suppress the blood flow response to nifedipine. This suggests that cardiac inotropes can influence non‐inflammatory changes in microvascular permeability.

British Journal of Pharmacology (1997) 122, 1160–1164; doi:10.1038/sj.bjp.0701480
Effect of pentoxifylline on the degradation of procollagen type I produced by human hepatic stellate cells in response to transforming growth factor‐β1
Authors: Giulio Romanelli Roberto , Caligiuri Alessandra , Carloni Vinicio , DeFranco Raffaella , Montalto Paolo , Ceni Elisabetta , Casini Alessandro , Gentilini Paolo , Pinzani Massimo 
Published: January 2005

Pentoxifylline (PTF) may act as a potential antifibrogenic agent by inhibiting cell proliferation and/or collagen deposition in cell type(s) responsible for the accumulation of extracellular matrix. The aim of the present study was to investigate at which level PTF may affect synthesis and degradation of type I collagen in human hepatic stellate cells (HSCs), a key source of connective tissue in fibrotic liver.
Procollagen type I synthesis and release were evaluated in cells maintained in serum free/insulin free medium for 48 h and then stimulated with transforming growth factor‐β1 (TGF‐β1) for different time periods in the presence or absence of PTF. TGF‐β1 caused an upregulation of procollagen I mRNA levels with a peak increase after 3–6 h of stimulation. This effect was followed by an increase in both the cell associated and the extracellular levels of the corresponding protein, with a peak effect at 9–12 h after the addition of TGF‐β1. Co‐incubation with PTF slightly but consistently reduced basal as well as stimulated procollagen I mRNA levels, with negligible effects on the cell‐associated expression of the corresponding protein. Conversely, PTF dose‐dependently reduced procollagen type I levels detected in supernatants from unstimulated and stimulated cells.
Pulse‐chase experiments employing L‐[3H]‐proline revealed that PTF was able to induce significantly the degradation of procollagen, mainly in the extracellular compartment. We next analysed the effect of PTF on the major pathway involved in type I collagen degradation. PTF did not affect the expression of metalloproteinase 1 (MMP‐1) mRNA both in basal and stimulated conditions, whereas it markedly reduced the expression of tissue inhibitor of metalloproteinase 1 (TIMP‐1) mRNA. Accordingly incubation with PTF increased the levels of ‘activated MMP‐1’ in cell supernatants in both basal and stimulated conditions.
These results suggest that the antifibrogenic action of PTF on human HSCs is mainly mediated by extracellular collagen degradation rather than by a reduction of collagen synthesis.

British Journal of Pharmacology (1997) 122, 1047–1054; doi:10.1038/sj.bjp.0701484
Quantification and distribution of α1‐adrenoceptor subtype mRNAs in human vas deferens: comparison with those of epididymal and pelvic portions
Authors: Moriyama Nobuo , Nasu Kimio , Takeuchi Takumi , Akiyama Katsuyoshi , Murata Satoshi , Nishimatsu Hiroaki , Yano Junichi , Tsujimoto Gozoh , Kawabe Kazuki 
Published: January 2005

This study was intended to quantify the amounts of the α1‐adrenoceptor subtype mRNAs in human vas deferens, and demonstrate the receptor subtype responsible for the vas contraction.
The RNase protection assay showed that the mean total amount of α1a mRNA was 7.4±2.2 pg/5 μg of poly (A)+ RNA (97.0% of the total α1 mRNA) in the epididymal portion (E‐vas) and 4.9±0.8 pg/5 μg of poly (A)+ RNA (96.3% of the total) in the pelvic portion (P‐vas). The E‐vas showed a tendency to have a greater α1a mRNA abundance than the P‐vas (P=0.11). The α1b and α1d mRNAs were absent or of extremely low abundance.
By an in situ hybridization, the α1a and α1d mRNAs were recognized in the smooth muscle cells of the E‐vas and the P‐vas, and the distribution pattern the same in both tissues. The α1b mRNA positive site was scarcely detectable in both vas portions.
In a functional study, l‐phenylephrine produced concentration‐dependent contraction in the E‐vas (Emax=2.24±0.70 g; pD2=5.32±0.09) and the P‐vas (Emax=2.46±0.46 g; pD2=5.07±0.12). KMD‐3213, a novel α1A‐adrenoceptor‐selective antagonist, caused parallel rightward shifts of the concentration–response curves for l‐phenylephrine. Apparent pKB values were 9.90±0.16 for the E‐vas and 9.71±0.17 for the P‐vas. There was no significant difference in Emax, pD2 or pKB estimates between the two portions.
We have found that α1a mRNA is predominant in the human vas deferens, and confirmed that contraction of this organ is mediated by the α1A‐adrenoceptor.

British Journal of Pharmacology (1997) 122, 1009–1014; doi:10.1038/sj.bjp.0701485
Tranilast inhibits the proliferation, chemotaxis and tube formation of human microvascular endothelial cells in vitro and angiogenesis in vivo
Authors: Isaji Masayuki , Miyata Hiroshi , Ajisawa Yoshiyuki , Takehana Yasuo , Yoshimura Nagahisa 
Published: January 2005

First developed as an antiallergic drug, tranilast inhibits chemical mediator release from mast cells. In the present study, we examine the effects of tranilast on angiogenesis in vitro and in vivo and discuss the application of tranilast for angiogenic diseases.
Tranilast inhibited significantly the proliferation (IC50: 136 μM, 95% confidence limits: 124–137 μM) and vascular endothelium growth factor (VEGF)‐induced chemotaxis (IC50: 135 μM, 95% confidence limits: 124–147 μM) of human dermal microvascular endothelial cells (HDMECs) at concentrations greater than 25 μg ml−1. No toxicity to HDMECs measuring by LDH release and no inhibitory effects on metalloproteinase (MMP)‐2 and MMP‐9 activity were observed even at 100 μg ml−1 (306 μM).
Tube formation of HDMECs cultured on the matrigel as an in vitro angiogenesis model was inhibited by tranilast in a concentration‐dependent manner. The IC50 value and 95% confidence limits were 175 μM and 151–204 μM, respectively.
In vivo angiogenesis was induced in mice by the subcutaneous injection of matrigel containing 30 ng ml−1 VEGF and 64 μg ml−1 heparin. Tranilast was administered orally twice a day for 3 days. Tranilast dose‐dependently suppressed angiogenesis in the matrigel and a significant change was observed at a dose of 300 mg kg−1.
These results indicate that tranilast is an angiogenesis inhibitor which may be beneficial for the improvement of angiogenic diseases such as proliferative diabetic retinopathy, age‐related macular degeneration, tumour invasion and rheumatoid arthritis.

British Journal of Pharmacology (1997) 122, 1061–1066; doi:10.1038/sj.bjp.0701493
Acute effects of nitric oxide blockade with L‐NAME on arterial haemodynamics in the rat
Authors: Hu Cheng‐Tao , Chang Kuo‐Chu , Wu Chia‐Yen , Chen Hsing I. 
Published: January 2005

We employed the technique of impedance spectral analysis to investigate the role of endogenous nitric oxide (NO) in the regulation of steady and pulsatile haemodynamics in Wistar Kyoto rat (WKY).
A total of 12 WKYs was anaesthetized with pentobarbitol sodium (40 mg kg−1, i.p.) and artificially ventilated with an animal respirator. The aortic pressure wave was monitored with a high fidelity Millar sensor, and aortic flow wave with an electromagnetic flow probe. The pressure and flow waves were subjected to Fourier transform for the analysis of impedance spectra.
The baseline cardiovascular parameters were mean arterial pressure (APm) 95±9 mmHg, heart rate (HR) 338±9 b.p.m., stroke volume (SV) 0.23±0.01 ml, cardiac output (CO) 77.8±1.6 ml min−1, total peripheral resistance (TPR) 98±11 (×103) dyne  s  cm−5, characteristic impedance (Zc) 2046±141 dyne  s  cm−5, arterial compliance at mean AP (Cm) 3.78±0.22 μl mmHg−1 and backward pulse wave (Pb) 12.9±0.6 mmHg.
An NO synthase inhibitor, NG‐nitro‐L‐arginine monomethyl ester (L‐NAME) was administered at graded intravenous doses. This agent caused dose‐dependent increases in AP and TPR with decreases in HR. At an accumulative dose of 10 mg kg−1, APm was increased by 29±3 mmHg (+31%) and TPR by 49±6 (×103) dyne  s  cm−5 (+50%), while HR was reduced by 37±5 b.p.m. (−11%) and CO by 10.4±0.8 ml min−1 (−14%). The pulsatile haemodynamics including Zc and Pb were slightly increased by 14–15%. Cm was decreased by 1.09 μl mmHg−1 (−29%). L‐NAME also did not significantly affect the ventricular work including the steady, oscillatory and total work.
Aminoguanidine, a specific inhibitor for inducible NO synthase (iNOS), in dose 10–60 mg kg−1 i.v. did not alter the AP, HR and other parameters. The result indicated that blockade of constitutive NOS, but not iNOS is involved in these changes.
Angiotensin II (Ang) in various infusion doses was used to produce a profile of AP increase similar to that caused by L‐NAME. Ang remarkably increased Zc, while TPR was moderately elevated. The pattern of haemodynamic changes was different from that following L‐NAME.
The results suggest that blockade of the endogenous NO affects predominantly the arterial pressure and peripheral resistance. The Windkessel functions such as arterial impedance and pulse wave reflection are slightly increased. Ventricular works are not significantly altered.

British Journal of Pharmacology (1997) 122, 1237–1243; doi:10.1038/sj.bjp.0701496
GR144053, a fibrinogen receptor antagonist, enhances the suppression of neointima formation by losartan, an angiotensin II receptor antagonist, in the injured carotid artery of hamster
Authors: Matsuno Hiroyuki , Kozawa Osamu , Niwa Masayuki , Kaida Takehiro , Hayashi Hideharu , Uematsu Toshihiko 
Published: January 2005

The present study investigated the inhibitory effect of losartan, a type 1 angiotensin II receptor (AT1) antagonist, and of combined treatment with losartan and GR144053, a fibrinogen receptor (GPIIb/IIIa) antagonist, on neointima formation subsequent to vascular injury in the hamster carotid artery. Vascular injury was achieved by a roughened‐tip 2F catheter and the neointimal area was measured up to 2 weeeks inducing the injury.
Compared to non‐treated hamsters (intimal area (IA)/internal elastic laminal area (IELA) ratio = 60.3±5.9%, n=12), losartan dissolved in drinking water (1, 3 and 10 mg kg−1 per day, n=8 each) reduced neointimal area dose‐dependently, a significant decrease (IA/IELA=39.7±5.6%) being attained with the highest dose when it was administered from 1 day before injury. However, neointima formation was not prevented even with the highest dose of losartan when the administration was started after injury.
When the administration of GR144053 (1.0 mg kg−1 per hour) via an implanted osmotic pump was started 30 min before the injury and continued for the next 2 weeks, no suppression of neointima formation was observed, although platelet aggregation evoked ex vivo by adenosine diphosphate (ADP) at the end of treatment period was efficiently inhibited.
In separate experiments in which 5‐bromo‐2‐deoxy‐Uridine (BrdU) was used to test smooth muscle cell (SMC) proliferation 1 and 7 days after injury, the ratio of SMC proliferation in the injured area was only slightly decreased by losartan when its administration was started after the injury, despite the marked reduction of SMC proliferation when treatment was started before the injury. Treatment with GR144053 as indicated above also significantly decreased the SMC proliferating index 1 day after the injury.
To examine the potential benefit of the coadministration of the GPIIb/IIIa antagonist with the AT1 receptor antagonist, GR144053 (1.0 mg kg−1 per hour) was combined with post‐injury treatment with losartan (10 mg kg−1 per day). This markedly reduced the proliferation of SMCs and significantly decreased the neointimal area (IA/IELA=31.2±4.6%) measured 2 weeks following the catheterization.
According to the results of a time‐dependent study in which GR144053 was given in combination with post injury treatment with losartan for 1, 3, 7 or 14 days, neointima formation could be reduced by treatment with GR144053 for just 7 days.
In conclusion, GR144053, a fibrinogen receptor antagonist, enhanced the inhibitory effect of losartan, an AT1 receptor antagonist, on neointima formation in the damaged carotid artery of hamsters.

British Journal of Pharmacology (1997) 122, 1099–1104; doi:10.1038/sj.bjp.0701500
Electrophysiological basis for the antiarrhythmic action and positive inotropy of HA‐7, a furoquinoline alkaloid derivative, in rat heart
Authors: Su Ming‐Jai , Chang Gwo‐Jyh , Wu Mei‐Hwan , Kuo Sheng‐Chu 
Published: January 2005

HA‐7, a new synthetic derivative of furoquinoline alkaloid, increased the contractile force of right ventricular strips and effectively suppressed the ischaemia‐reperfusion induced polymorphic ventricular tachyrhythmias in adult rat heart (EC50=2.8 μM).
In rat ventricular myocytes, HA‐7 concentration‐dependently prolonged the action potential duration (APD) and decreased the maximal rate of rise of the action potential upstroke (V̇max). The action potential amplitude and resting membrane potential were also reduced, but to a smaller extent. The prolongation of APD by HA‐7 was prevented by pretreating the cells with 1 mM 4‐AP.
Voltage clamp experiments revealed that HA‐7 decreased the maximal current amplitude of INa (IC50=4.1 μM) and caused a negative shift of its steady‐state inactivation curve and slowed its rate of recovery from inactivation. The use‐dependent inhibition of INa by HA‐7 was enhanced at a higher stimulation rate. The L‐type Ca2+ current (ICa) was also reduced, but to a lesser degree (IC50=5.3 μM, maximal inhibition=31.8%).
This agent also influenced the time‐ and voltage‐dependent K+ currents. The prolongation of APD was associated with an inhibition of a 4‐AP sensitive transient outward K+ current (Ito) (IC50=2.9 μM) and a slowly inactivating, steady‐state outward current (Iss) (IC50=2.5 μM). The inhibition of Ito by HA‐7 was associated with an acceleration of its time constant of inactivation. HA‐7 suppressed Ito in a time‐dependent manner and caused a significant negative shift of the voltage‐dependent steady‐state inactivation curve but did not affect its rate of recovery from inactivation.
At higher concentrations, the inward rectifier K+ current (IK1) was also inhibited but to a less extent. Its slope conductance after 3, 10 and 30 μM HA‐7 was decreased by 24±4%, 41±5% and 54±8%, respectively.
We conclude that HA‐7 predominantly blocks Ito and Na+ channels and that it also weakly blocks Ca2+ and IK1 channels. These changes alter the electrophysiological properties of the heart and terminate the ischaemia reperfusion induced ventricular arrhythmia. The significant Ito inhibition and minimal ICa suppression may afford an opportunity to develop an effective antiarrhythmic agent linked with positive inotropy.