Abstract:
:1 Both phasic and tonic responses to KCl 160 mM were reduced by Ca2+ deprivation. After 90 min, the phasic response was abolished but 13 +/- 1.5% of the tonic response remained. This resistant component was still present if the Ca2+-free solution contained EGTA 0.1 mM. The tonic response was more resistant to deprivation in the prostatic half, while the phasic was more resistant in the epididymal half. KCl-induced contractions were completely restored 5 min after readmission of Ca2+. 2 Both the phasic and the tonic responses were reduced on lowering, and increased on raising [Ca2+]0. In 0.1 mM Ca2+, the phasic response was abolished, but 23 +/- 4% of the tonic response remained (mainly attributable to the prostatic half). These resistant contractions indicate that some of the extracellular Ca2+, especially in the prostatic half, is bound with high affinity, probably to the plasma membrane. 3 Incubation with LaCl3 (0.3-10 mM) for 15 min inhibited the phasic response more than the tonic. After incubation for 1 h, 3 mM LaCl3 abolished both phases. It is concluded that La3+ blocks Ca2+ channels most readily when they are opened during the spike. Hydralazine (0.76-5.1 mM) resembled LaCl3 in that it reduced the phasic response with little effect on the tonic. 4 MnCl2 (0.3-10mM) reduced the phasic but increased the tonic response at all concentrations. The augmenting effect may be due to release of intracellular Ca2+ or to inhibition of Ca2+ efflux. 5 The tonic response was inhibited more than the phasic response by nifedipine (0.002-0.01 microM), methoxyverapamil (0.06-2 microM), verapamil (0.2-1 microM), flunarizine (0.2-100 microM) and diazoxide (22-650 microM). With higher concentrations, only flunarizine, remained selective for the tonic response. It is concluded that flunarizine blocks Ca2+ channels most readily when opened during sustained spike-free depolarization. 6 Methoxyverapamil 48 microM and verapamil 100 microM virtually abolished both phases of the contraction to KCl 160 mM, but no more than 80% inhibition could be produced with nifedipine. It is concluded that voltage-sensitive Ca2+ channels exist in two sub-types, one of which is blocked by nifedipine, and both are blocked by verapamil, methoxyverapamil and flunarizine. Nitroprusside 17 microM had no effect on the phasic response but inhibited the nifedipine-resistant component of the tonic response. 7 Increasing [ca2+]0 reversed the effects of verapamil, methoxyverapamil, nifedipine and MnCl2, but not the effects of LaCl3. 8 Dantrolene sodium (1.25-25 microM) had no effect on KCl-induced contractions.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Hay DW,Wadsworth RMdoi
10.1111/j.1476-5381.1982.tb09195.xsubject
Has Abstractpub_date
1982-05-01 00:00:00pages
103-13issue
1eissn
0007-1188issn
1476-5381journal_volume
76pub_type
杂志文章abstract::Mast cells participate in allergies, and also in immunity and inflammation by secreting proinflammatory cytokines. Flavonoids are naturally occurring polyphenolic plant compounds, one group of which -- the flavonols, inhibits histamine and some cytokine release from rodent basophils and mast cells. However, the effect...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0706246
更新日期:2005-08-01 00:00:00
abstract::The dependence of neurotransmitter secretion on external calcium ions during development of opiate tolerance in the mouse vas deferens was studied. The writhing response of mice to an i.p. injection of acetylcholine was inhibited by morphine. Reversal of this antinociceptive effect of morphine during chronic treatment...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1984.tb16524.x
更新日期:1984-12-01 00:00:00
abstract::1. The pulmonary vasculature is constantly exposed to oxygen and reactive oxygen species such as nitric oxide (NO) and superoxide anions which can combine at a near diffusion limited rate, to form the powerful, oxidant, peroxynitrite (ONOO-). When formed in large amounts, ONOO- is thought to contribute to tissue injur...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701162
更新日期:1997-06-01 00:00:00
abstract::1. To determine the role of G protein-coupled receptor kinases (GRKs) in the regulation of endogenous secretin receptor responsiveness, we have transiently overexpressed both wild-type (WT) and dominant negative mutant (DNM) GRKs in NG108-15 mouse neuroblastoma x rat glioma hybrid cells and investigated the effects of...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705101
更新日期:2003-02-01 00:00:00
abstract::1 In cats anaesthetized with pentobarbitone and vagotomized, observations were made on the phrenic nerve action potential and the diaphragm electromyogram (EMG) at constant end-tidal Pco(2). Arterial blood pressure was stabilized by intravenous infusions of noradrenaline.2 Intravenous administration of saxitoxin (STX)...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1980.tb10419.x
更新日期:1980-02-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Quercetin is a natural polyphenolic flavonoid that displays anti-diabetic properties in vivo. Its mechanism of action on insulin-secreting beta cells is poorly documented. In this work, we have analysed the effects of quercetin both on insulin secretion and on the intracellular calcium concentrat...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12194
更新日期:2013-07-01 00:00:00
abstract::1. The concentrations of adrenaline and noradrenaline in the brains of chickens (Gallus domesticus) have been determined using two different methods of fluorimetric analysis.2. The concentrations of adrenaline, noradrenaline and also dopamine were found to increase with age, as did the relative amount of adrenaline pr...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1970.tb10605.x
更新日期:1970-09-01 00:00:00
abstract::1. Column chromatography with Agarose A50m followed by Sephadex G100 was used to separate a fraction (extract II) in the molecular weight range 12,000 to 14,000 daltons from saline extracts of the sea anemone, Tealia felina. 2. Extract II inhibited histamine-induced contractions of the guinea-pig ileum and produced ha...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1981.tb09115.x
更新日期:1981-02-01 00:00:00
abstract::1. Cannabinoids are potent inhibitors of endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxations. We set out to study the mechanism underlying this effect and the possible role of cannabinoid-induced changes in intercellular gap junction communication. 2. In cultured endothelial cells, Delta(9)-tetrahyd...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704776
更新日期:2002-07-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Rhythmical transient constrictions of the lymphatic vessels provide the means for efficient lymph drainage and interstitial tissue fluid balance. This activity is critical during inflammation, to avoid or limit oedema resulting from increased vascular permeability, mediated by the release of vari...
journal_title:British journal of pharmacology
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更新日期:2009-12-01 00:00:00
abstract:BACKGROUND AND PURPOSE:We investigated whether or not kinin receptors play a role in diabetic blood-retinal barrier breakdown, which is a leading cause of vision loss. EXPERIMENTAL APPROACH:Blood-retinal barrier breakdown was quantified using Evans blue, and expression of kinin B(1) receptor mRNA was measured using qu...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/bjp.2008.48
更新日期:2008-05-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Subset of macrophages within the atheroma plaque displays a high glucose uptake activity. Nevertheless, the molecular mechanisms and the pathophysiological significance of this high glucose need remain unclear. While the role for hypoxia and hypoxia inducible factor 1α has been demonstrated, the ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.15358
更新日期:2020-12-29 00:00:00
abstract::1. The effects of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), an inhibitor of soluble guanylyl cyclase (sGC), were investigated in aortic rings and ventricular cardiomyocytes from rats. The production of cyclic GMP was stimulated by NO.-donors or carbachol. Additionally, the effects of ODQ were studied in cytos...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0702608
更新日期:1999-06-01 00:00:00
abstract::1. The modification by Bay K 8644 of the vasodilator effects of nifedipine, diltiazem, nicorandil and nitroglycerin was investigated in the femoral arterial bed of anaesthetized dogs. 2. The right femoral artery was cannulated and its arterial bed was perfused with autologous blood at a constant pressure slightly high...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1988.tb11415.x
更新日期:1988-01-01 00:00:00
abstract::Inhibition of myocardial Ca2+ channels was investigated for three dihydropyridines with different structural features: Ro 18-3981, darodipine (PY 108-068) and nifedipine. Ro 18-3981 contains a sulphamoyl acetyl side-chain. In voltage-clamps experiments with isolated cardiac myocytes of guinea-pig, Ro 18-3981 caused a ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1987.tb08983.x
更新日期:1987-05-01 00:00:00
abstract::1. Mesangial cell proliferation is observed in a number of kidney diseases. The sympathetic cotransmitter ATP is suspected to play a major role in proliferative processes. Therefore, the effects of exogenous ATP on human mesangial cells in culture were studied. 2. Fresh human kidney cortex was processed to obtain mesa...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705358
更新日期:2003-07-01 00:00:00
abstract::1. Measurements were made of the uptake, metabolism and release of [(3)H]-adrenaline by human platelets in citrated plasma or in an artificial medium.2. Radioactive adrenaline was not taken up at 0-2 degrees C. At 37 degrees C there was a slow uptake which continued for at least 5 hours.3. About half of the radioactiv...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1970.tb09903.x
更新日期:1970-08-01 00:00:00
abstract::1. Neural crest material from neurula stage Xenopus embryos was tissue cultured as small aggregates of cells or a single cell suspension. Isolated pigment cells differentiated after 2 days in culture. 2. Melatonin (10(-15) to 10(-13) M) induced pigment granule condensation; it was 10,000 times more effective than any ...
journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1977.tb07554.x
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abstract::1. Experiments were performed in anaesthetized rabbits to examine the effects of calcitonin gene-related peptide (CGRP) and the CGRP antagonist CGRP8-37 on blood flow to the medial collateral ligament of the knee joint. 2. Topical application of CGRP (10(-13) to 10(-9) mol) to the exposed external surface of eight kne...
journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1997-08-01 00:00:00
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journal_title:British journal of pharmacology
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更新日期:1998-07-01 00:00:00
abstract::1. Neurotensin was infused intravenously, in the presence or absence of intravenous atropine or intraarterial tetrodotoxin, into dogs anaesthetized with sodium pentobarbitone. Net and unidirectional fluxes of sodium and blood flows in the ileum were measured. Arterial and mesenteric venous blood pressures, haematocrit...
journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1988.tb11506.x
更新日期:1988-05-01 00:00:00
abstract::Despite its long-standing reputation as a foul smelling and toxic gas that is associated with the decay of biological matter,hydrogen sulphide (H2S) has emerged as an important regulator of cardiovascular homoeostasis. H2S promotes a number of cellular signals that regulate metabolism, cardiac function and cell surviv...
journal_title:British journal of pharmacology
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doi:10.1038/bjp.2008.359
更新日期:2008-11-01 00:00:00
abstract::1. The effect of the calcitonin gene-related peptide antagonist (CGRP8-37, 400 nmol kg-1, i.v.) on the increased blood flow induced by calcitonin gene related peptide (CGRP), vasodilator prostaglandins, and topical capsaicin was measured with a laser Doppler blood flow meter in rat abdominal skin. 2. The saphenous ner...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1993.tb13878.x
更新日期:1993-10-01 00:00:00
abstract:BACKGROUND AND PURPOSE:While selective, bitter tasting, TAS2R agonists can relax agonist-contracted airway smooth muscle (ASM), their mechanism of action is unclear. However, ASM contraction is regulated by Ca²⁺ signalling and Ca²⁺ sensitivity. We have therefore investigated how the TAS2R10 agonists chloroquine, quinin...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12460
更新日期:2014-02-01 00:00:00
abstract::1 The effect of local elevation of leucocyte cyclic adenosine 3',5'-monophosphate (cyclic AMP) content on the continued migration of leucocytes to a site of acute inflammation was studied in the pleural cavity of rats. 2 Leucocyte cyclic AMP levels were elevated by injecting with the irritant into the pleural cavity d...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1977.tb07742.x
更新日期:1977-06-01 00:00:00
abstract::Proteinase-activated receptor-2 (PAR-2) is expressed throughout the gastrointestinal tract including the pancreas, and may be involved in digestive functions. The aim of our study was to evaluate a potential role for PAR-2 in regulating salivary and pancreatic exocrine secretion in vivo. PAR-2-activating peptides (PAR...
journal_title:British journal of pharmacology
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更新日期:2000-04-01 00:00:00
abstract::1. A study has been made of serum, mixed and parotid salivary levels attained in normal volunteers following oral dosage of 500 mg phenoxymethylpenicillin tablets, 500 mg crushed phenoxymethylpenicillin tablets in capsules, 500 mg ampicillin, 500 mg cloxacillin and 500 mg cephalexin.2. High mixed saliva levels were ob...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1971.tb07173.x
更新日期:1971-09-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Agmatine, a putative neurotransmitter, plays a vital role in learning and memory. Although it is considered an endogenous ligand of imidazoline receptors, agmatine exhibits high affinity for α-adrenoceptors, NOS and NMDA receptors. These substrates within the locus coeruleus (LC) are critically i...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13531
更新日期:2016-09-01 00:00:00
abstract::(1) Here, we introduce a beta-casomorphin-5-derived cyclic pentapeptide, cCD-2 (Tyr-cyclo[d-Orn-Tyr(Bzl)-Pro-Gly]), which inhibits the cell growth of a variety of human cancer cell lines. (2) This opioid-derived peptide possesses only low affinity for mu-receptors, but enhances the agonist binding to mu-receptors in v...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0705416
更新日期:2003-09-01 00:00:00
abstract::Extracellular nucleotides can activate a common purinoceptor mediating various cell responses. In this study we report that stimulation of rat mesangial cells with ATP and UTP leads to a rapid activation of the protein kinase B/Akt (PKB) pathway. Time-course studies reveal a rapid and transient phosphorylation of both...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704748
更新日期:2002-06-01 00:00:00