bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipopolysaccharide enhances bradykinin‐induced signal transduction via activation of Ras/Raf/MEK/MAPK in canine tracheal smooth muscle cells
Authors: Luo Shue‐Fen , Wang Chuan‐Chwan , Chiu Chi‐Tso , Chien Chin‐Sung , Hsiao Li‐Der , Lin Chien‐Huang , Yang Chuen‐Mao 
Published: January 2005

Bacterial lipopolysaccharide (LPS) was found to induce inflammatory responses and to enhance bronchial hyperreactivity to several contractile agonists. However, the implication of LPS in the pathogenesis of bronchial hyperreactivity was not completely understood. Therefore, in this study, we investigated the effect of LPS on mitogen‐activated protein kinase (MAPK) activation associated with potentiation of bradykinin (BK)‐induced inositol phosphates (IPs) accumulation and Ca2+ mobilization in canine cultured tracheal smooth muscle cells (TSMCs).
LPS stimulated phosphorylation of p42/p44 MAPK in a time‐ and concentration‐dependent manner using a Western blot analysis against a specific phosphorylated form of MAPK antibody. Maximal stimulation of the p42 and p44 MAPK isoforms occurred after 7 min‐incubation and the maximal effect was achieved with 100 μg ml−1 LPS.
Pretreatment of TSMCs with LPS potentiated BK‐induced IPs accumulation and Ca2+ mobilization. However, there was no effect on the IPs response induced by endothelin‐1, 5‐hydroxytryptamine, and carbachol. In addition, pretreatment with PDGF‐BB enhanced BK‐induced IPs response.
These enhancements by LPS and PDGF‐BB might be due to an increase in BK B2 receptor density (Bmax) in TSMCs, characterized by competitive inhibition of [3H]‐BK binding using B1 and B2 receptor‐selective reagents.
The enhancing effects of LPS and PDGF‐BB were attenuated by PD98059, an inhibitor of MAPK kinase (MEK), suggesting that the effect of LPS may share a common signalling pathway with PDGF‐BB in TSMCs.
Furthermore, overexpression of dominant negative mutants, H‐Ras‐15A and Raf‐N4, significantly suppressed p42/p44 MAPK activation induced by LPS and PDGF‐BB, indicating that Ras and Raf may be required for activation of these kinases.
These results suggest that the augmentation of BK‐induced responses produced by LPS might be, at least in part, mediated through activation of Ras/Raf/MEK/MAPK pathway in TSMCs.

British Journal of Pharmacology (2000) 130, 1799–1808; doi:10.1038/sj.bjp.0703489
Functional, biochemical and molecular biological evidence for a possible β3‐adrenoceptor in human near‐term myometrium
Authors: Bardou M , Loustalot C , Cortijo J , Simon B , Naline E , Dumas M , Esteve S , Croci T , Chalon P , Frydman R , Sagot P , Manara L , Morcillo E J , Advenier C 
Published: January 2005

The possible existence of a β3‐adrenoceptor (β3‐AR) in human near‐term myometrium was investigated by in vitro functional and biochemical studies and analysis of mRNA expression.
SR 59119A and SR 59104A and CGP 12177 (two selective agonists and a partial agonist, respectively, of the β3‐AR), salbutamol and terbutaline (β2‐AR agonists) each produced a concentration‐dependent relaxation of the myometrial spontaneous contractions. There were no differences in pD2 values for the relaxing potencies of terbutaline, salbutamol, CGP 12177 and SR 59119A. The rank order for their relaxing efficacies was SR 59119A>SR 59104A>terbutaline∼salbutamol∼CGP 12177 (Emax=52±7%, 42±12% and ∼ 30% respectively).
Propranolol, a β1‐ and β2‐AR antagonist, and ICI 118551, a β2‐AR antagonist (both at 0.1 μM), did not affect the SR 59119A‐induced relaxation whereas SR 59230A, a selective β3‐AR antagonist (1 μM), significantly reduced the maximal relaxing effect of SR 59119A.
SR 59119A and salbutamol induced a significant increase in cyclic AMP levels that was antagonized by SR 59230A but not by propranolol for SR 59119A, and by propranolol but not by SR 59230A for salbutamol.
The β3‐AR mRNA was positively expressed in myometrium preparations in a reverse transcription polymerase chain assay.
The results presented provide the first evidence for the existence of the β3‐AR subtype in human near‐term myometrium and suggest that the effects of SR 59119A might be mediated through an increase in cyclic AMP level.

British Journal of Pharmacology (2000) 130, 1960–1966; doi:10.1038/sj.bjp.0703491
Pharmacological characterization of volume‐sensitive, taurine permeable anion channels in rat supraoptic glial cells
Authors: Brès Vanessa , Hurbin Amandine , Duvoid Anne , Orcel Hélène , Moos Françoise C , Rabié Alain , Hussy Nicolas 
Published: January 2005

To characterize the volume‐sensitive, osmolyte permeable anion channels responsible for the osmodependent release of taurine from supraoptic nucleus (SON) astrocytes, we investigated the pharmacological properties of the [3H]‐taurine efflux from acutely isolated SON.
Taurine release induced by hypotonic stimulus (250 mosmol l−1) was not antagonized by the taurine transporter blocker guanidinoethyl sulphonate, confirming the lack of implication of the transporter.
The osmodependent release of taurine was blocked by a variety of Cl− channel inhibitors with the order of potency: NPPB>niflumic acid>DPC>DIDS>ATP. On the other hand, release of taurine was only weakly affected by other compounds (dideoxyforskolin, 4‐bromophenacyl bromide, mibefradil) known to block volume‐activated anion channels in other cell preparations, and was completely insensitive to tamoxifen, a broad inhibitor of these channels.
Although the molecular identity of volume‐sensitive anion channels is not firmly established, a few genes have been postulated as potential candidates to encode such channels. We checked the expression in the SON of three of them, ClC3, phospholemman and VDAC1, and found that the transcripts of these genes are found in SON neurons, but not in astrocytes. Similar observation was previously reported for ClC2.
In conclusion, the osmodependent taurine permeable channels of SON astrocytes display a particular pharmacological profile, suggesting the expression of a particular type or subtype of volume‐sensitive anion channel, which is likely to be formed by yet unidentified proteins.

British Journal of Pharmacology (2000) 130, 1976–1982; doi:10.1038/sj.bjp.0703492
Dual interaction of agmatine with the rat α2D‐adrenoceptor: competitive antagonism and allosteric activation
Authors: Molderings G J , Menzel S , Kathmann M , Schlicker E , Göthert M 
Published: January 2005

In segments of rat vena cava preincubated with [3H]‐noradrenaline and superfused with physiological salt solution, the influence of agmatine on the electrically evoked [3H]‐noradrenaline release, the EP3 prostaglandin receptor‐mediated and the α2D‐adrenoceptor‐mediated inhibition of evoked [3H]‐noradrenaline release was investigated.
Agmatine (0.1–10 μM) by itself was without effect on evoked [3H]‐noradrenaline release. In the presence of 10 μM agmatine, the prostaglandin E2(PGE2)‐induced EP3‐receptor‐mediated inhibition of [3H]‐noradrenaline release was not modified, whereas the α2D‐adrenoceptor‐mediated inhibition of [3H]‐noradrenaline release induced by noradrenaline, moxonidine or clonidine was more pronounced than in the absence of agmatine. However, 1 mM agmatine antagonized the moxonidine‐induced inhibition of [3H]‐noradrenaline release.
Agmatine concentration‐dependently inhibited the binding of [3H]‐clonidine and [3H]‐rauwolscine to rat brain cortex membranes (Ki values 6 μM and 12 μM, respectively). In addition, 30 and 100 μM agmatine increased the rate of association and decreased the rate of dissociation of [3H]‐clonidine resulting in an increased affinity of the radioligand for the α2D‐adrenoceptors.
[14C]‐agmatine labelled specific binding sites on rat brain cortex membranes. In competition experiments. [14C]‐agmatine was inhibited from binding to its specific recognition sites by unlabelled agmatine, but not by rauwolscine and moxonidine.
In conclusion, the present data indicate that agmatine both acts as an antagonist at the ligand recognition site of the α2D‐adrenoceptor and enhances the effects of α2‐adrenoceptor agonists probably by binding to an allosteric binding site of the α2D‐adrenoceptor which seems to be labelled by [14C]‐agmatine.

British Journal of Pharmacology (2000) 130, 1706–1712; doi:10.1038/sj.bjp.0703495
Comparison of zofenopril and lisinopril to study the role of the sulfhydryl‐group in improvement of endothelial dysfunction with ACE‐inhibitors in experimental heart failure
Authors: Buikema H , Monnink S H J , Tio R A , Crijns H J G M , De Zeeuw D , Van Gilst W H 
Published: January 2005

We evaluated the role of SH‐groups in improvement of endothelial dysfunction with ACE‐inhibitors in experimental heart failure. To this end, we compared the vasoprotective effect of chronic treatment with zofenopril (plus SH‐group) versus lisinopril (no SH‐group), or N‐acetylcysteine (only SH‐group) in myocardial infarcted (MI) heart failure rats.
After 11 weeks of treatment, aortas were obtained and studied as ring preparations for endothelium‐dependent and ‐independent dilatation in continuous presence of indomethacin to avoid interference of vasoactive prostanoids, and the selective presence of the NOS‐inhibitor L‐NMMA to determine NO‐contribution.
Total dilatation after receptor‐dependent stimulation with acetylcholine (ACh) was attenuated (−49%, P<0.05) in untreated MI (n=11), compared to control rats with no‐MI (n=8). This was in part due to impaired NO‐contribution in MI (−50%, P<0.05 versus no‐MI). At the same time the capacity for generation of biologically active NO after receptor‐independent stimulation with A23187 remained intact.
Chronic treatment with n‐acetylcysteine (n=8) selectively restored NO‐contribution in total dilatation to ACh. In contrast, both ACE‐inhibitors fully normalized total dilatation to ACh, including the part mediated by NO (no significant differences between zofenopril (n=10) and lisinopril (n=8)).
Zofenopril, but not lisinopril, additionally potentiated the effect of endogenous NO after A23187‐induced release from the endothelium (+100%) as well as that of exogenous NO provided by nitroglycerin (+22%) and sodium nitrite (+36%) (for all P<0.05 versus no‐MI).
We conclude that ACE‐inhibition with a SH‐group has a potential advantage in improvement of endothelial dysfunction through increased activity of NO after release from the endothelium into the vessel wall. Furthermore, this is the first study demonstrating the selective normalizing effect of N‐actylcysteine on NO‐contribution to ACh‐induced dilatation in experimental heart failure.

British Journal of Pharmacology (2000) 130, 1999–2007; doi:10.1038/sj.bjp.0703498
A comparative study of the ability of calcitonin gene‐related peptide and adrenomedullin13–52 to modulate microvascular but not thermal hyperalgesia responses
Authors: Chu Duc Quyen , Choy ManKin , Foster Paul , Cao Thong , Brain Susan D 
Published: January 2005

Calcitonin gene‐related peptide (CGRP), a neuropeptide, is a potent vasodilator. Adrenomedullin (ADM) is suggested to be produced by vascular cells in inflamed tissue. ADM shares some structural homology with CGRP. We have compared the ability of CGRP and ADM to modulate microvascular and thermal hyperalgesic responses in rat skin. Vasodilator activity was assessed by laser Doppler flowmetry, inflammatory oedema by the extravascular accumulation of intravenously‐injected labelled albumin, and neutrophil accumulation by tissue myeloperoxidase, in dorsal skin. Hyperalgesia was assessed by a thermal hyperalgesimeter in paw skin.
ADM (10–300 pmol) was 3 fold less potent than CGRP (3–100 pmol) as a direct vasodilator. CGRP (30 pmol) potentiated oedema formation induced by mediators of increased microvascular permeability, as expected (P<0.01). However, ADM (30–100 pmol) was without a potentiating effect, although ADM (300 pmol) was effective (P<0.01). By comparison ADM (100 pmol) potentiated neutrophil accumulation induced by interleukin‐1β (P<0.05), whereas CGRP (30 pmol) did not. No thermal hyperalgesia was observed to either CGRP or ADM, when given as single or repeated treatments.
Thus despite a dilator activity neither CGRP nor ADM appears to mediate hyperalgesic activity in the periphery. However ADM, like CGRP, has the ability to potentiate inflammatory oedema formation and, in addition, ADM can potentiate neutrophil accumulation.
ADM may, as suggested for CGRP, act as a modulator of the vascular phases of inflammation. The property of the two compounds of evoking differential microvascular responses and neutrophil accumulation may be due to differing mechanisms of action.

British Journal of Pharmacology (2000) 130, 1589–1596; doi:10.1038/sj.bjp.0703502
Localization and function of ET‐1 and ET receptors in small arteries post‐myocardial infarction: Upregulation of smooth muscle ETB receptors that modulate contraction
Authors: Gray Gillian A , Mickley Emma J , Webb David J , McEwan Pauline E 
Published: January 2005

Endothelin‐1 (ET‐1) has been implicated as a mediator of increased vascular tone during development of heart failure post‐myocardial infarction (MI). In the present study, expression and pharmacology of ET‐1 and its receptors were studied in small mesenteric arteries from rats at 5 and 12 weeks after coronary artery ligation for induction of MI, or sham‐operation.
In vessels from sham‐operated and 5 week post‐MI rats preproET‐1mRNA, immunoreactive (ir) ET‐1, ETB receptor mRNA and irETB receptor were confined to the endothelium, while ETA receptor mRNA was distributed throughout the media. At 12 weeks post‐MI, preproET‐1 and irETA receptor localization was similar but ETB receptor mRNA and immunoreactivity were detectable in the media, as well as the endothelium.
The ET‐1 concentration‐response curve (CRC) was progressively shifted to the right in pressurized third generation mesenteric arteries from 5 and 12 week post‐MI rats relative to sham‐operated rats, with no change in the maximum. The ETA receptor antagonist BQ‐123 (10−6 M) induced a rightward shift of the ET‐1 CRC in all vessels. Desensitization of ETB receptors, by exposure to SRTX S6c (3×10−8 M), had no effect on the ET‐1 CRC in vessels from 5 week post‐MI or sham‐op rats but induced a leftward shift in vessels from 12 week post‐MI rats.
These results identify the endothelium as the primary site of ET‐1 synthesis in small arteries and the ETA receptor as mediating the effects of ET‐1 in these vessels. However, ETB receptor expression increases in vascular smooth muscle post‐MI and is linked to mechanisms that inhibit the contractile response to ET‐1.

British Journal of Pharmacology (2000) 130, 1735–1744; doi:10.1038/sj.bjp.0703503
Nitroparacetamol exhibits anti‐inflammatory and anti‐nociceptive activity
Authors: Al‐Swayeh O A , Futter L E , Clifford R H , Moore P K 
Published: January 2005

Nitroparacetamol (NCX‐701) is a newly synthesized nitric oxide‐releasing derivative of paracetamol. Following i.p. administration, nitroparacetamol inhibits carrageenan‐induced hindpaw oedema formation (ED50, 169.4 μmol kg−1) and mechanical hyperalgesia (ED50, 156 μmol kg−1) in the rat. In contrast, the parent compound, paracetamol, exhibits no significant anti‐oedema activity in this model (ED50>1986 μmol kg−1, i.p.) and is markedly less potent than nitroparacetamol as an inhibitor of carrageenan‐mediated hyperalgesia (ED50, 411.6 μmol kg−1, i.p.). In a second model of nociception (inhibition of acetic acid induced abdominal constrictions in the mouse), nitroparacetamol administered orally (ED50, 24.8 μmol kg−1), was again considerably more potent than paracetamol (ED50, 506 μmol kg−1, p.o.). Thus, compared with paracetamol, nitroparacetamol not only exhibits augmented antinociceptive activity in both rat and mouse but, intriguingly, is also anti‐inflammatory over a similar dose range.British Journal of Pharmacology (2000) 130, 1453–1456; doi:10.1038/sj.bjp.0703509
Ginsenoside‐induced relaxation of human bronchial smooth muscle via release of nitric oxide
Authors: Tamaoki J , Nakata J , Kawatani K , Tagaya E , Nagai A 
Published: January 2005

Ginsenoside, an extract of Panax ginseng, is an essential constituent of anti‐asthmatic Chinese herbal medicine. To elucidate whether ginsenoside affects airway smooth muscle tone and, if so, what the mechanism of action is, we studied relaxant responses of human bronchial strips under isometric condition in vitro, and directly measured the release of nitric oxide (NO) by an amperometric sensor for this molecule.
Addition of ginsenoside relaxed the tissues precontracted with acetylcholine in a dose‐dependent manner, the maximal relaxation and the ginsenoside concentration required to produce 50% relaxation being 67±8% and 210±29 μg ml−1, respectively.
The relaxant responses to ginsenoside were inhibited by NG‐nitro‐L‐arginine methylester (L‐NAME) and removal of the epithelium, but not by NG‐nitro‐D‐arginine methylester (D‐NAME) or tetrodotoxin. This inhibitory effect of L‐NAME was reversed by L‐arginine but not by D‐arginine.
Addition of ginsenoside to the medium containing bronchial tissues dose‐dependently increased NO‐selective electrical current, and this effect was greatly attenuated by the epithelial removal or Ca2+‐free medium.
Ginsenoside also increased tissue cyclic GMP contents, an effect that was abolished in the presence of L‐NAME.
It is concluded that ginsenoside induces relaxation of human bronchial smooth muscle via stimulation of NO generation predominantly from airway epithelium and cyclic GMP synthesis. This action might account for the anti‐asthmatic effect of Panax ginseng.

British Journal of Pharmacology (2000) 130, 1859–1864; doi:10.1038/sj.bjp.0703511
No involvement of nicotinic receptors in the facilitation of acetylcholine outflow in mouse cortex in the presence of neostigmine and atropine
Authors: Iannazzo Lydia , Majewski Henryk 
Published: January 2005

The role of nicotinic and muscarinic receptors in the modulation of acetylcholine release was studied using field stimulated mouse cortex slices incubated with [3H]‐choline.
Both acetylcholine (100 μM) and the cholinesterase inhibitor neostigmine (100 μM) inhibited the stimulation‐induced (S‐I) outflow of radioactivity but in the presence of atropine (0.3 μM) an enhancement was seen, which may be indicative of facilitatory nicotinic receptors.
Mecamylamine (100 μM) was unable to antagonize the enhancement seen in the presence of acetylcholine and atropine. The nicotinic agonist dimethylphenylpiperazinium (30 μM) did not facilitate S‐I outflow of radioactivity.
A range of nicotinic blockers had no effect on the enhancement seen in the presence of neostigmine and atropine, nor did indomethacin, the 5HT3 antagonist MDL 7222 nor the NMDA antagonist MK‐801.
The inability to block this effect suggests that nicotinic receptors are not involved. We postulate, at least for neostigmine, that the facilitation is an artefact because of the use of [3H]‐choline as a radiotracer whereby the efflux of radioactivity is enhanced because the radiolabelled acetylcholine is not metabolized to choline and therefore flows out of the tissue more readily.

British Journal of Pharmacology (2000) 130, 2008–2014; doi:10.1038/sj.bjp.0703512
Barnidipine block of L‐type Ca2+ channel currents in rat ventricular cardiomyocytes
Authors: Wegener Jörg W , Meyrer Hans , Rupp Johanna , Nawrath Hermann 
Published: January 2005

The effects of barnidipine and nifedipine on L‐type Ca2+ current (ICa(L)) were investigated in ventricular cardiomyocytes from rats.
Both barnidipine and nifedipine reduced ICa(L) in a concentration and voltage dependent manner; the EC50 were 80 and 130 nM at a holding potential of −80 mV, respectively, and 18 and 6 nM at −40 mV, respectively.
Both drugs induced a leftward shift of the steady‐state inactivation curve of ICa(L).
Using a twin pulse protocol, the relationships between the amount of block of ICa(L) by either drug, seen during the second pulse, and the length of the first pulse were described by monoexponential functions reflecting onset of block, dependent on drug concentration. The onset of block by barnidipine was three times faster than that by nifedipine.
With both drugs, recovery of ICa(L) was 50 times slower than under control conditions and described by monoexponential functions reflecting offset of block (independent of drug concentration). The offset of block with barnidipine was three times slower than that with nifedipine.
The time constants of block and unblock of ICa(L) by both drugs were used to calculate binding and unbinding and to predict their effects at two frequencies.
It is suggested that barnidipine exhibits a higher affinity to the inactivated Ca2+ channel state as compared to nifedipine.

British Journal of Pharmacology (2000) 130, 2015–2023; doi:10.1038/sj.bjp.0703514
Sphingosine‐1‐phosphate and sphingosylphosphorylcholine constrict renal and mesenteric microvessels in vitro
Authors: Bischoff Angela , Czyborra Peter , Fetscher Charlotte , Meyer zu Heringdorf Dagmar , Jakobs Karl H , Michel Martin C 
Published: January 2005

Sphingolipids such as sphingosine‐1‐phosphate (SPP) and sphingosylphosphorylcholine (SPPC) can act both intracellularly and at G‐protein‐coupled receptors, some of which were cloned and designated as Edg‐receptors.
Sphingolipid‐induced vascular effects were determined in isolated rat mesenteric and intrarenal microvessels. Additionally, sphingolipid‐induced elevations in intracellular Ca2+ concentration were measured in cultured rat aortic smooth muscle cells.
SPPC and SPP (0.1–100 μmol l−1) caused concentration‐dependent contraction of mesenteric and intrarenal microvessels (e.g. SPPC in mesenteric microvessels pEC50 5.63±0.17 and Emax 49±3% of noradrenaline), with other sphingolipids being less active. The vasoconstrictor effect of SPPC in mesenteric microvessels was stereospecific (pEC50 D‐erythro‐SPPC 5.69±0.08, L‐threo‐SPPC 5.31±0.06) and inhibited by pretreatment with pertussis toxin (Emax from 44±5 to 19±4%), by chelation of extracellular Ca2+ with EGTA and by nitrendipine (Emax from 40±6 to 6±1 and 29±6%, respectively). Mechanical endothelial denudation or NO synthase inhibition did not alter the SPPC effects, while indomethacin reduced them (Emax from 87±3 to 70±4%).
SPP and SPPC caused transient increases in intracellular Ca2+ concentrations in rat aortic smooth muscle cells in a pertussis toxin‐sensitive manner.
Our data demonstrate that SPP and SPPC cause vasoconstriction of isolated rat microvessels and increase intracellular Ca2+ concentrations in cultured rat aortic smooth muscle cells. These effects appear to occur via receptors coupled to pertussis toxin‐sensitive G‐proteins. This is the first demonstration of effects of SPP and SPPC on vascular tone and suggests that sphingolipids may be an hitherto unrecognized class of endogenous regulators of vascular tone.

British Journal of Pharmacology (2000) 130, 1871–1877; doi:10.1038/sj.bjp.0703515