Abstract:
:1. We investigated whether K(+) can act as an endothelium-derived hyperpolarizing factor (EDHF) in isolated small renal arteries of Wistar-Kyoto rats. 2. Acetylcholine (0.001 - 3 microM) caused relaxations that were abolished by removal of the endothelium. However, acetylcholine-induced relaxations were not affected by the nitric oxide (NO) synthase inhibitor N:(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM), by L-NAME plus the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ, 1 microM) or by L-NAME plus the cyclo-oxygenase inhibitor indomethacin (10 microM). In rings precontracted with high-K(+)(60 mM) physiological salt solution in the presence of L-NAME, acetylcholine-induced relaxations were abolished. 3. L-NAME-resistant relaxations were abolished by the large-conductance Ca(2+)-activated K(+) channel inhibitor charybdotoxin plus the small-conductance Ca(2+)-activated K(+) channel inhibitor apamin, while the inward rectifier K(+) channel inhibitor Ba(2+) or the gap junction inhibitor 18alpha-glycyrrhetinic acid had no effect. Acetylcholine-induced relaxation was unchanged by ouabain (10 microM) but was partially inhibited by a higher concentration (100 microM). 4. In half of the tissues tested, K(+)(10 mM) itself produced L-NAME-resistant relaxations that were blocked by ouabain (10 microM) and partially reduced by charybdotoxin plus apamin, but not affected by 18alpha-glycyrrhetinic acid or Ba(2+). However, K(+) did not induce relaxations in endothelium-denuded tissues. 5. In conclusion, acetylcholine-induced relaxations in this tissue are largely dependent upon hyperpolarization mechanisms that are initiated in the endothelium but do not depend upon NO release. K(+) release cannot account for endothelium-dependent relaxation and cannot be an EDHF in this artery. However, K(+) itself can initiate endothelium-dependent relaxations via a different pathway from acetylcholine, but the mechanisms of K(+)-induced relaxations remain to be clarified.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Jiang F,Dusting GJdoi
10.1038/sj.bjp.0703965subject
Has Abstractpub_date
2001-04-01 00:00:00pages
1558-64issue
7eissn
0007-1188issn
1476-5381journal_volume
132pub_type
杂志文章abstract:BACKGROUND AND PURPOSE:Dexpramipexole, a drug recently tested in patients with amyotrophic lateral sclerosis (ALS,) is able to bind F1Fo ATP synthase and increase mitochondrial ATP production. Here, we have investigated its effects on experimental ischaemic brain injury. EXPERIMENTAL APPROACH:The effects of dexpramipe...
journal_title:British journal of pharmacology
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doi:10.1111/bph.13790
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abstract::Monocytes and macrophages provide key targets for the action of novel anti-inflammatory therapeutics targeted at inhibition of PDE4 cAMP-specific phosphodiesterases. PDE4 enzymes provide the dominant cAMP phosphodiesterase activity in U937 human monocytic cells. Differentiation of U937 monocytic cells to a macrophage-...
journal_title:British journal of pharmacology
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abstract::1. The effects of sulphone have been studied on kinin production in dog plasma and on capillary permeability in the skin of rabbits.2. Dog plasma was used as a substrate for pancreatic kallikrein in vitro and the addition of sulphone caused an inhibition of kinin production, which was dependent on the concentration of...
journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1969.tb09534.x
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abstract:BACKGROUND AND PURPOSE:Skeletal muscle is the predominant site for glucose disposal and fatty acid consumption. Emerging evidence indicates that the crosstalk between adipose tissue and skeletal muscle is critical in maintaining insulin sensitivity and lipid homeostasis. The current study was designed to investigate wh...
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abstract::1 Urocortin is a vasodilator peptide related to corticotrophin-releasing factor, which may protect endothelial function during coronary ischemia-reperfusion (I-R). The aim of this study was to study the mechanisms of this protective effect. 2 Hearts from Sprague-Dawley rats were isolated and perfused at constant flow ...
journal_title:British journal of pharmacology
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abstract::1. The present study was designed to evaluate the nature of intervening agents in L-DOPA- and dopamine-induced neurotoxicity in Neuro-2A cells. 2. In the absence of cells and in conditions of light protection, at 37 degrees C, L-DOPA or dopamine (1 mM) in culture medium degraded spontaneously in a time-dependent manne...
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更新日期:2002-12-01 00:00:00
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更新日期:2010-09-01 00:00:00
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journal_title:British journal of pharmacology
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abstract::1. By use of the whole-cell configuration of the patch-clamp technique, membrane currents induced by cyclopiazonic acid (CPA; an inhibitor of the sarcoplasmic reticulum (SR) calcium-ATPase) were investigated in single smooth muscle cells freshly dispersed from the mouse anococcygeus. Voltage-dependent calcium currents...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15228.x
更新日期:1996-02-01 00:00:00
abstract::1. The effects of beta-adrenoceptor blockade on the changes in plasma renin activity (PRA) following angiotensin enzyme (ACE) inhibition were investigated in pentobarbitone-chloralose anaesthetized dogs. 2. ACE-inhibition, with enalapril (2 mg kg-1), caused a significant reduction in systemic arterial blood pressure (...
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pub_type: 杂志文章
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更新日期:1992-06-01 00:00:00
abstract::In the clinic, low efficacy positive GABAA modulators might be preferred to high efficacy positive modulators insofar as low efficacy modulators might have comparatively less abuse and dependence liability. Drug discrimination was used to examine the behavioral effects of L-838,417 and bretazenil, two low efficacy pos...
journal_title:British journal of pharmacology
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更新日期:2006-02-01 00:00:00
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journal_title:British journal of pharmacology
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pub_type: 杂志文章
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更新日期:1994-02-01 00:00:00
abstract::1. The mechanisms underlying the vasodilator response to urocortin are incompletely understood. The present study was designed to examine the role of endothelial nitric oxide and Ba(2+)-sensitive K(+) channels in the endothelium-dependent component of urocortin-induced relaxation in the rat left anterior descending co...
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更新日期:2002-03-01 00:00:00
abstract::1. The effects of paracetamol and lysine acetylsalicylate (L-AS) on high-threshold mechanonociceptors have been investigated by recording neural activity from the inflamed ankle joint in anaesthetized rats with mild adjuvant-induced monoarthritis. 2. Paracetamol (50 mg kg-1, i.v.) and L-AS (100 mg kg-1, i.v., equivale...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1991.tb12404.x
更新日期:1991-09-01 00:00:00
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journal_title:British journal of pharmacology
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更新日期:2001-01-01 00:00:00
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更新日期:1970-06-01 00:00:00
abstract::1. Juvenile male rats treated with parachlorophenylalanine showed hair loss round the head and neck extending down the chest and abdomen.2. Treated isolated rats did not have this loss of hair, while untreated animals living in the same cage as treated rats lost their hair. The loss therefore seems to be caused by inc...
journal_title:British journal of pharmacology
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更新日期:1970-02-01 00:00:00
abstract::1. Imidazoline binding sites have been reported to be present in the locus coeruleus (LC). To investigate the role of these sites in the control of LC neuron activity, we studied the effect of imidazolines using in vivo and in vitro single-unit extracellular recording techniques. 2. In anaesthetized rats, local (27 pm...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0702255
更新日期:1998-12-01 00:00:00
abstract::1. Contraction of the rabbit isolated saphenous vein is mediated by a heterogeneous endothelin (ET) receptor population. This study has characterized these receptor subtypes by use of several pharmacologically distinct ET receptor agonists and antagonists. 2. ET-1, ET-3, sarafotoxin S6c (STXc) and [Ala3,11]ET-1 produc...
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更新日期:1995-04-01 00:00:00
abstract::1. The brain cytoprotective effects of a putative calcium-associated protein kinase inhibitor, HA1077, as well as a calcium entry blocker nicardipine were evaluated in models of cerebral ischaemia in Mongolian gerbils. Morphological changes characterizing delayed neuronal death of selectively vulnerable CA1 pyramidal ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1991.tb12355.x
更新日期:1991-08-01 00:00:00