bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bradykinin B2‐receptor‐mediated modulation of membrane currents in guinea‐pig cardiomyocytes
Authors: Sakamoto Naoya , Uemura Hiroko , Hara Yukio , Saito Toshihiro , Masuda Yoshiaki , Nakaya Haruaki 
Published: January 2005

In order to define the electrophysiological mechanism(s) responsible for bradykinin (BK)‐induced positive inotropic and chronotropic responses in isolated guinea‐pig atria, effects of BK on the membrane currents were examined in isolated atrial cells using patch clamp techniques.
BK (0.1–1000 nM) increased the L‐type Ca2+ current (ICa), which was recorded from enzymatically‐dissociated atrial myocytes by the nystatin‐perforated patch method, in a concentration‐dependent fashion, and the calculated EC50 value for increasing ICa was 5.2 nM. In conventional ruptured patch experiments, BK inhibited the muscarinic acetylcholine receptor‐operated K+ current (IK.ACh) that was activated by the muscarinic agonist carbachol (1 μM) with an EC50 value of 0.57 nM. Both the increase in ICa and the decrease in IK.ACh were blocked by HOE140, a selective bradykinin B2 receptor antagonist.
The BK‐induced inhibition of IK.ACh was significantly attenuated by staurosporine and calphostin C, protein kinase C inhibitors. In addition, the IK.ACh inhibition by BK was also attenuated by the tyrosine kinase inhibitor genistein or tyrphostin but not by daidzein, an inactive analogue of genistein. However, neither protein kinase C inhibitor nor tyrosine kinase inhibitor affected the BK‐induced increase in ICa.
In the presence and absence of muscarinic stimulation, BK prolonged the action potential recorded from the atrial cells in the current clamp mode.
We conclude that BK increases ICa and decreases IK.ACh in atrial cells, resulting in positive inotropic and chronotropic responses in atrial preparations. Protein kinase C activation, and possibly tyrosine kinase activation, may be involved in the B2‐receptor‐mediated IK.ACh inhibition.

British Journal of Pharmacology (1998) 125, 283–292; doi:10.1038/sj.bjp.0702060
Increased vascular permeability by a specific agonist of protease‐activated receptor‐2 in rat hindpaw
Authors: Kawabata Atsufumi , Kuroda Ryotaro , Minami Takeshi , Kataoka Kazuo , Taneda Mamoru 
Published: January 2005

The present study examined the effect of intraplantar (i.pl.) administration of a selective agonist of protease‐activated receptor (PAR)‐2, SLIGRL‐NH2(PP6‐NH2), on vascular permeability in rat hindpaw. PP6‐NH2, administered i.pl. at 10–100 nmol per paw, enhanced vascular permeability and caused oedema formation in rat hindpaw. SLIGRL (PP6‐OH) and trypsin, by i.pl. administration, also elicited an increase in vascular permeability, although i.pl. administration of the mixture of constituent amino acids of PP6‐OH at an equivalent dose did not. The PP6‐NH2‐induced increase in vascular permeability was abolished by repeated pretreatment with compound 48/80 to deplete bioactive amines in mast cells. These findings suggest that the activation of PAR‐2 induces acute inflammation, at least partially, via mast cell degranulation in rat hindpaw.British Journal of Pharmacology (1998) 125, 419–422; doi:10.1038/sj.bjp.0702063
Point mutation increases a form of the NK1 receptor with high affinity for neurokinin A and B and septide
Authors: Ciucci Alessandra , Palma Carla , Manzini Stefano , Werge Thomas M 
Published: January 2005

The binding modalities of substance P and neurokinin A on the wild type and Gly166 to‐Cys mutant NK1 receptors expressed on CHO cells were investigated in homologous and heterologous binding experiments using both radiolabelled substance P and neurokinin A.
On the wild type NK1 receptor NKA displaces radiolabelled substance P with very low apparent affinity, despite its high‐affinity binding constant (determined in homologous binding experiments). The Gly166 to‐Cys substitution in the NK1 tachykinin receptor greatly enhances the apparent affinity of neurokinin A in competition for radiolabelled substance P, but it does not change the binding constant of neurokinin A. The mutation, thereby, eliminates the discrepancy between the low apparent affinity and the high binding constant of neurokinin A.
On the wild type receptor the binding capacity of neurokinin A is significantly smaller than that of substance P. In contrast, the two tachykinins bind to approximately the same number of sites on the mutant receptor.
Simultaneous mass action law analysis of binding data in which multiple radioligands were employed in parallel demonstrated that a one‐site model was unable to accommodate all the experimental data, whereas a two‐site model provided a dramatically better description.
These two receptor‐sites display equally high affinity for substance P, while neurokinin A strongly discriminates between a high and a low affinity component. The binding affinities of neurokinin A are not affected by the mutation, which instead specifically alters the distribution between receptor sites in favour of a high affinity neurokinin A binding form.
The low apparent affinity and binding capacity of neurokinin A on the wild type receptor results from neurokinin A binding with high affinity only to a fraction of the sites labelled by substance P. The mutation increases the proportion of this site, and consequently enhances the apparent affinity and binding capacity of neurokinin A.
The binding modalities of septide‐like ligands (i.e. neurokinin B, SP(6–11), SP‐methyl ester) are affected similarly to neurokinin A and are better resolved into two sites. The mutation leaves the affinity of these ligands for the two receptor forms unchanged, but increases the fraction of high‐affinity sites. On the other hand, the binding of non‐peptide and peptide antagonists (SR140.333 and FK888) behaved similarly to substance P with a single high affinity site that is unaffected by the mutation.
These findings may suggest that the NK1 receptor exists in two different forms with similar affinity for substance P and NK1 antagonists, but with a high and a low affinity for neurokinin A and septide‐like ligands. Hence, the Gly166 in the NK1 receptor would seem to control the distribution between a pan‐reactive form and a substance P‐selective form of the receptor.

British Journal of Pharmacology (1998) 125, 393–401; doi:10.1038/sj.bjp.0702070
Andrographolide suppresses the expression of inducible nitric oxide synthase in macrophage and restores the vasoconstriction in rat aorta treated with lipopolysaccharide
Authors: Chiou Wen‐Fei , Lin Jin‐Jung , Chen Chieh‐Fu 
Published: January 2005

We investigated whether andrographolide, a diterpenoid lactone found at Andrographis paniculata, influences the induction of the inducible nitric oxide synthase (iNOS) in RAW264.7 cells activated by bacterial endotoxin (LPS), as well as in the rats with endotoxic shock and in aortic rings treated with LPS.
Incubation of RAW264.7 cells with andrographolide (1 to 50 μM) inhibited the LPS (1 μg ml−1)‐induced nitrite accumulation in concentration‐ and time‐dependent manners. Maximum inhibition was observed when andrographolide was added together with LPS and decreased progressively as the interval between andrographolide and LPS was increased to 20 h.
Western blot analysis demonstrated that iNOS expression was markedly attenuated in the presence of andrographolide for 6–24 h, suggesting that andrographolide inhibited iNOS protein induction.
Thoracic aorta incubation with LPS (300 ng ml−1) for 5 h in vitro exhibited a significant decrease in the maximal contractile response to phenylephrine (10−9–10−5 M). Andrographolide (30 μM) restored the contractile response to control level.
In anaesthetized rats, LPS (10 mg kg−1, i.v.) caused a fall in mean arterial blood pressure (MAP) from 116±4 to 77±5 mmHg. The pressor effect of phenylephrine (10 μg ml−1, i.v.) was also significantly reduced at 30, 60, 120 and 180 min after LPS injection. In contrast, animals pretreated with andrographolide (1 mg kg−1, i.v., 20 min prior to LPS) maintained a significantly higher MAP when compared to LPS‐rats given with vehicle. Administration of andrographolide 60 min after LPS caused a increase in MAP and significantly reversed the reduction of the pressor response to phenylephrine.
Our results indicated that andrographolide inhibits nitrite synthesis by suppressing expression of iNOS protein in vitro. And, this inhibition of iNOS synthesis may contribute to the beneficial haemodynamic effects of andrographolide in endotoxic shock.

British Journal of Pharmacology (1998) 125, 327–334; doi:10.1038/sj.bjp.0702073
Essential role for endothelin ETB receptors in fever induced by LPS (E. coli) in rats
Authors: Fabricio Aline S C , Silva Carlos A A , Rae Giles A , D'Orléans‐Juste Pedro , Souza Glória E P 
Published: January 2005

The influence of endothelin receptor antagonists on febrile responses to E. coli lipopolysaccharide (LPS), interleukin‐1β (IL‐1β), tumour necrosis factor‐α (TNF‐α) and endothelin‐1 (ET‐1) was assessed in conscious rats.
Intravenous (i.v.) LPS (5.0 μg kg−1) markedly increased rectal temperature to a peak of 1.30°C over baseline at 2.5 h. Pretreatment with the mixed endothelin ETA/ETB receptor antagonist bosentan (10 mg kg−1, i.v.) or the selective endothelin ETB receptor antagonist BQ‐788 (N‐cis‐2,6‐dimethyl‐piperidinocarbonyl‐L‐γ‐methylleucyl‐D‐1‐methoxycarboyl‐D‐norleucine; 3 pmol, into a lateral cerebral ventricle–i.c.v.) reduced the peak response to LPS to 0.90 and 0.75°C, respectively. The selective endothelin ETA receptor antagonist BQ‐123 (cyclo[D‐Trp‐D‐Asp‐Pro‐D‐Val‐Leu]; 3 pmol, i.c.v.) was ineffective.
Increases in temperature caused by IL‐1β (180 fmol, i.c.v.), TNF‐α (14.4 pmol, i.c.v.) or IL‐1β (150 pmol kg−1, i.v.) were unaffected by BQ‐788 (3 pmol, i.c.v.).
Central injection of endothelin‐1 (0.1 to 3 fmol, i.c.v.) caused slowly‐developing and long‐lasting increases in rectal temperature (starting 2 h after administration and peaking at 4–6 h between 0.90 and 1.15°C) which were not clearly dose‐dependent. The response to endothelin‐1 (1 fmol, i.c.v.) was prevented by BQ‐788, but not by BQ‐123 (each at 3 pmol, i.c.v.). Intraperitoneal pretreatment with the cyclo‐oxygenase inhibitor indomethacin (2 mg kg−1), which partially reduced LPS‐induced fever, did not modify the hyperthermic response to endothelin‐1 (3 fmol, i.c.v.).
Therefore, central endothelin(s) participates importantly in the development of LPS‐induced fever, via activation of a prostanoid‐independent endothelin ETB receptor‐mediated mechanism possibly not situated downstream from IL‐1β or TNF‐α in the fever cascade.

British Journal of Pharmacology (1998) 125, 542–548; doi:10.1038/sj.bjp.0702075
Bradykinin‐evoked sensitization of neuropeptide release from afferent neurons in the guinea‐pig lung
Authors: Schuligoi R , Peskar B A , Donnerer J , Amann R 
Published: January 2005

It has been shown that bradykinin (BK) causes sensitization of airway sensory neurons and an enhancement of the cough reflex in guinea‐pigs. In the present study, the guineapig isolated perfused lung was used to investigate the possible enhancement by BK of histamine‐evoked neuropeptide release from peripheral terminals of primary afferent neurons, and to determine the contribution of cyclooxygenase products of arachidonate metabolism to this effect.
The lung was perfused with oxygenated physiological salt solution containing peptidase inhibitors (thiorphan, bestatin and captopril, 1 μM each). BK and histamine were added to the perfusate for 10 and 5 min, respectively.
BK alone (0.1 μM) evoked the release of 10.35±2.4 fmol immunoreactive calcitonin gene‐related peptide (CGRP), histamine alone (100 μM) evoked the release of 12.7±1.6 fmol CGRP. Stimulation with 100 μM histamine in the presence of 0.1 μM BK (added 5 min before histamine and present during histamine) evoked the release of 67.1±5.3 fmol CGRP.
Prostaglandin (PG) release was stimulated by BK (418±71 pmol 15‐keto‐13,14‐dihydro‐PGF2α and 345±59 pmol 6‐keto‐PGF1α), and, to a lesser extent, by histamine (36.1±7.4 pmol 15‐keto‐13,14‐dihydro‐PGF2α, and 24.6±3.9 pmol 6‐keto‐PGF1α). Prostaglandin release induced by histamine in the presence of BK was not significantly higher than with BK alone.
Indomethacin (5 μM) as well as the bradykinin B2 receptor antagonist HOE140 (icatibant, 1 μM) inhibited prostaglandin release following stimulation with histamine in combination with BK. CGRP release evoked by histamine in combination with BK was attenuated by indomethacin and HOE140 to 22.1±7.8 fmol and 16.4±3.8 fmol, respectively, significantly less than the value obtained in control experiments (67.1±5.3 fmol).
The results suggest that BK‐induced stimulation of prostaglandin synthesis results in facilitation of histamine–evoked release of pro‐inflammatory neuropeptides from afferent neurons, a mechanism that probably becomes relevant during inflammation, and that can be blocked by a bradykinin B2 receptor antagonist.

British Journal of Pharmacology (1998) 125, 388–392; doi:10.1038/sj.bjp.0702079
Subtype selectivity of the novel nonpeptide neuropeptide Y Y1 receptor antagonist BIBO 3304 and its effect on feeding in rodents
Authors: Wieland H A , Engel W , Eberlein W , Rudolf K , Doods H N 
Published: January 2005

The novel Y1‐selective argininamide derivative BIBO 3304 ((R)‐N‐[[4‐(aminocarbonylaminomethyl)phenyl]methyl]‐N2‐(diphenylacetyl)‐argininamide trifluoroacetate) has been synthesized and was examined for its subtype selectivity, its in vitro antagonistic properties and its food intake inhibitory properties.
BIBO 3304 displayed subnanomolar affinity for both the human and the rat Y1 receptor (IC50 values 0.38±0.06 nM and 0.72±0.42 nM, respectively). The inactive enantiomer of BIBO 3304 (BIBO 3457) had low affinity for both the human and rat Y1 receptor subtype (IC50>1000 nM). BIBO 3304 showed low affinity for the human Y2 receptor, human and rat Y4 receptor as well as for the human and rat Y5 receptor (IC50 values >1000 nM).
30 μg BIBO 3304 administered into the paraventricular nucleus inhibited the feeding response induced by 1 μg NPY as well as the hyperphagia induced by a 24 h fast implying a role for Y1 receptors in NPY mediated feeding. The inactive enantiomer had no effect.
BIBO 3304 inhibits neither the galanin nor the noradrenaline induced orexigenic response, but it blocked feeding behaviour elicited by both [Leu31, Pro34]NPY and NPY (3–36) suggesting an interplay between different NPY receptor subtypes in feeding behavior.
The present study reveals that BIBO 3304 is a subtype selective nonpeptide antagonist with subnanomolar affinity for the Y1 receptor subtype that significantly inhibits food intake induced by application of NPY or by fasting.

British Journal of Pharmacology (1998) 125, 549–555; doi:10.1038/sj.bjp.0702084
Metabolism of the vitamin D3 analogue EB1089 alters receptor complex formation and reduces promoter selectivity
Authors: Quack Marcus , Mørk Hansen Christina , Binderup Ernst , Kissmeyer Anne‐Marie , Carlberg Carsten 
Published: January 2005

1α,25‐dihydroxyvitamin3 (VD) is a nuclear hormone that has important cell regulatory functions but also a strong calcemic effect. EB1089 is a potent antiproliferative VD analogue, which has a modified side chain resulting in increased metabolic stability and a selective functional profile. Since EB1089 is considered for potential systemic application, it will be investigated to what extent its recently identified metabolites (hydroxylated at positions C26 and C26a) contribute to biological profile of the VD analogue.
Limited protease digestion analysis demonstrated that EB1089 is able to stabilize the high affinity ligand binding conformation of the VDR, starting at concentrations of 0.1 nM and affecting up to 80% of all receptor molecules. The metabolites EB1445 and EB1470 showed to be 100 fold less potent than EB1089, whereas the remaining three metabolites (EB1435, EB1436 and EB1446) showed a clearly reduced ability to stabilize the high affinity ligand binding conformation. Interestingly, at pharmacological concentrations all EB1089 metabolites stabilized a second, apparently lower affinity conformation to a much higher extent than EB1089.
In reporter gene assays all metabolites showed lower potency than EB1089. Moreover, the preference of EB1089 for activation of VDR binding to sites formed by inverted palindromic arrangements spaced by nine nucleotide (IP9‐type VD response elements) appeared to be reduced (with EB1445 and EB1470) or completely lost (with EB1435, EB1436 and EB1446). The ranking of EB1089 and its metabolites that was obtained by limited protease digestion and reporter gene assays was confirmed by an analysis of their antiproliferative effect in breast cancer cells.
The potency and selectivity of the EB1089 metabolites in mediating gene regulatory effects was found to be drastically reduced in comparison to the parent compound suggesting that the contribution of the metabolites to the biological effect of EB1089 is minor. However, the compounds showed to be interesting tools for understanding the selective biological profile of EB1089.

British Journal of Pharmacology (1998) 125, 607–614; doi:10.1038/sj.bjp.0702086
Ramipril‐induced delayed myocardial protection against free radical injury involves bradykinin B2 receptor‐NO pathway and protein synthesis
Authors: Jin Zhu‐Qiu , Chen Xiu 
Published: January 2005

The aim of the present study was to examine whether ramipril induces delayed myocardial protection against free radical injuries ex vivo and to determine the possible role of the bradykinin B2–nitric oxide (NO) pathway, prostaglandins(PGs) and protein synthesis in this delayed adaptive response.
Rats were pretreated with ramipril (10 or 50 μg kg−1, i.v.) and hearts were isolated after 24, 48 and 72 h. Langendorff hearts were subjected to 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) free radical‐induced injury.
Left ventricular developed pressure (LVDP) and its maximal increase velocity (+dP/dtmax), coronary flow (CF), heart rate (HR), lactate dehydrogenase (LDH) in coronary effluent and thiobarbituric acid reactive substances (TBARS) in the myocardium were measured.
The results showed that in the DPPH control group, 20 min after free radical‐induced injury, LVDP, +dP/dtmax, CF, HR declined, whereas TBARS and LDH increased significantly. The above cardiac function parameters were significantly improved in RAM‐pretreated rats after 24 and 48 h.
Pretreatment with HOE 140, the selective bradykinin B2 receptor antagonist, NG‐nitro‐L‐arginine, the NO synthase inhibitor, and actinomycin D, the RNA transcription inhibitor, prior to ramipril injection abolished the beneficial effects of ramipril at 24 h while indomethacin, a cyclooxygenase inhibitor, pretreatment had no effect on ramipril‐induced delayed protection.
In conclusion, ramipril induces delayed myocardial protection against free radical injury in the rat heart. This delayed protection was sustained for 48 h, is associated with the bradykinin B2 receptor–NO pathway and depends on protein but not prostaglandin synthesis.

British Journal of Pharmacology (1998) 125, 556–562; doi:10.1038/sj.bjp.0702089
Potentiation of barbiturate‐induced alterations in presynaptic noradrenergic function in rat frontal cortex by imidazol(in)e α2‐adrenoceptor agonists
Authors: Dalley J W , Parker C A , Wülfert E , Hudson A L , Nutt D J 
Published: January 2005

In order to resolve the extent to which presynaptic noradrenergic mechanisms contribute to the anaesthetic‐sparing effects of α2‐adrenoceptor agonists in vivo microdialysis was used to investigate the combined effects of sodium pentobarbitone and imidazol(in)e α2‐adrenoceptor agonists on extracellular levels of noradrenaline (NA) in the rat frontal cortex.
Dialysate levels of NA were markedly reduced by the addition of TTX (2 μM) or by the removal of calcium in the perfusate. These data imply that dialysate NA levels are ultimately dependent on exocytotic release mechanisms from afferent coeruleo‐cortical neurones.
Systemic administration of sodium pentobarbitone (85 mg kg−1, i.p.) induced general anaesthesia and reduced NA levels by 92% after 30 min. The restoration of basal levels 90 min later was closely associated with a return of the corneal blink reflex.
Basal NA levels in conscious animals were not affected by an intravenous infusion of equally radioactive solutions of either imidazoline (clonidine) or imidazole (mivazerol) α2‐adrenoceptor agonists. The dose rate employed for each compound was 2 μg kg−1 h−1 over 2 h.
The co‐administration of intravenous clonidine or mivazerol, each at 2 μg kg−1 h−1 for 2 h, with sodium pentobarbitone (85 mg kg−1, i.p.), produced a marked and prolonged reduction in NA efflux. After 2 h, NA levels remained suppressed by 95% (clonidine) and 80% (mivazerol) and animals remained deeply anaesthetized.
The accumulation of tritium in brain tissue was 42–73% lower across all brain regions examined after [3H]‐mivazerol administration than after [3H]‐clonidine administration. Sodium pentobarbitone did not alter the accumulation of tritium in brain tissue after the administration of either α2‐adrenoceptor agonist.
These data demonstrate that α2‐adrenoceptor agonists potentiate the inhibitory effects of sodium pentobarbitone on extracellular levels of NA in the frontal cortex. Further studies will be necessary to establish a causal role of noradrenergic mechanisms in the potentiation of anaesthesia by selective α2‐adrenoceptor agonists.

British Journal of Pharmacology (1998) 125, 441–446; doi:10.1038/sj.bjp.0702091
Vascular smooth muscle cell hypertrophy induced by glycosylated human oxyhaemoglobin
Authors: Peiró Concepción , Angulo Javier , Rodríguez‐Mañas Leocadio , Llergo José L , Vallejo Susana , Cercas Elena , Sánchez‐Ferrer Carlos F 
Published: January 2005

Nonenzymatic protein glycosylation is a possible mechanism contributing to oxidative stress and vascular disease in diabetes. In this work, the influence of 14%‐glycosylated human oxyhaemoglobin (GHHb), compared to the non‐glycosylated protein (HHb), was studied on several growth parameters of rat cultured vascular smooth muscle cells (VSMC). A role for reactive oxygen species was also analysed.
Treatment of VSMC for 48 h with GHHb, but not with HHb, increased planar cell surface area in a concentration dependent manner. The threshold concentration was 10 nM, which increased cell size from 7965±176 to 9411±392 μm2. Similarly, only GHHb enhanced protein content per well in VSMC cultures.
The planar surface area increase induced by 10 nM GHHb was abolished by superoxide dismutase (SOD; 50–200 u ml−1), deferoxamine (100 nM–100 μM), or dimethylthiourea (1 mM), while catalase (50–200 u ml−1) or mannitol (1 mM) resulted in a partial inhibition of cell size enhancement.
When a known source of oxygen free radicals was administered to VSMC, the xanthine/xanthine oxidase system, the results were analogous to those produced by GHHb. Indeed, enhancements of cell size were observed, which were inhibited by SOD, deferoxamine, or catalase.
These results indicate that, at low concentrations, GHHb induces hypertrophy in VSMC, this effect being mediated by superoxide anions, hydrogen peroxide, and/or hydroxyl radicals. Therefore, glycosylated proteins can have a role in the development of the structural vascular alterations associated to diabetes by enhancing oxidative stress.

British Journal of Pharmacology (1998) 125, 637–644; doi:10.1038/sj.bjp.0702097