Abstract:
:1. We have examined the mechanisms by which the K(+)-channel blocker 4-aminopyridine (4-AP) can dose-dependently increase both basal [3H]-noradrenaline ([3H]-NA) release and the [3H]-NA release evoked by electrical stimulation, but not the release of [3H]-acetylcholine ([3H]-ACh), from slices of rat hippocampus. 2. Both the electrically evoked and the 4-AP-induced release were blocked by tetrodotoxin (TTX) (3 microM). The Ca(2+)-dependence of the 4-AP-induced release (EC50 0.15 mM) was, however, different from that of the electrically evoked [3H]-NA release (EC50 0.76 mM). 3. The 4-AP-induced release could be inhibited by CdCl2(10 microM) and omega-conotoxin (30 nM), but not by nifedipine (1 microM). 4. Transmitter release evoked by 100 microM 4-AP could be blocked by the alpha 2-adrenoceptor agonist, UK 14,304 (0.1 microM) and by the A1-receptor agonist R-N6-phenylisopropyl adenosine (R-PIA, 1 microM) and increased by the alpha 2-adrenoceptor antagonist, yohimbine (1 microM), both in 0.25 and 1.3 mM Ca(2+)-containing medium. By contrast, the effect of alpha 2-adrenoceptor agonist and antagonists on transmitter release evoked by electrical stimulation was markedly reduced in the presence of 4-AP (100 microM). 5. The results suggest that 4-AP can depolarize some nerve endings in the central nervous system, leading to transmitter release that is dependent on nerve impulses and Ca2+. Furthermore, the fact that alpha 2-receptors and adenosine A1 receptor agonists can influence the release of NA evoked by 4-AP suggests that these drugs may have actions that are independent of blockade of aminopyridine-sensitive K(+)-channels.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Hu PS,Fredholm BBdoi
10.1111/j.1476-5381.1991.tb12247.xsubject
Has Abstractpub_date
1991-03-01 00:00:00pages
764-8issue
3eissn
0007-1188issn
1476-5381journal_volume
102pub_type
杂志文章abstract::The effect of docosahexaenoic acid (DHA) on nitric oxide (NO) production and inducible NO synthase (iNOS) expression induced by interleukin (IL)-1beta, and whether the effect of DHA is related to its effect on mitogen-activated protein kinase (MAPK) activation were investigated in cultured rat vascular smooth muscle c...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0704768
更新日期:2002-06-01 00:00:00
abstract:BACKGROUND AND PURPOSE:The regulation of vascular soluble guanylyl cyclase (sGC) expression by nitric oxide (NO) is still under discussion. In vitro, NO has been shown to downregulate the expression of sGC but it is unclear if this mechanism is operative in vivo and occurs during nitrate treatment. EXPERIMENTAL APPROA...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/bjp.2008.269
更新日期:2008-10-01 00:00:00
abstract::1. Antidepressant drugs are known to inhibit some changes evoked by glucocorticoids, as well as a hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis, often observed in depression. 2. The aim of present study was to investigate effects of various antidepressant drugs on the glucocorticoid-mediated gene transcri...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703445
更新日期:2000-07-01 00:00:00
abstract::A number of cholinoceptor antagonists used in the treatment of Parkinson's disease were examined for their ability to antagonize either the muscarinic receptor-mediated inhibition of dopamine D1 receptor-stimulated adenylyl cyclase or the muscarinic receptor-mediated stimulation of [3H]-inositol phosphates ([3H]-IPs) ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15474.x
更新日期:1996-06-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Extrahepatic vasodilation and increased intrahepatic vascular resistance represent attractive targets for the medical treatment of portal hypertension in liver cirrhosis. In both dysfunctions, dysregulation of the contraction-mediating Rho kinase plays an important role as it contributes to alter...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2009.00158.x
更新日期:2009-05-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Chronic stress impairs GABAA (GABA type A) receptor-mediated inhibition in the hypothalamic paraventricular nucleus (PVN). It is not clear whether GABAB receptor function is also altered. We hypothesize that chronic stress alters GABAB receptor function in PVN corticotrophin-releasing hormone (CR...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13924
更新日期:2017-09-01 00:00:00
abstract:BACKGROUND AND PURPOSE:The aim of the current study was to investigate the role of arachidonic acid (AA) metabolism via cyclooxygenase (COX) in the endothelial dysfunction of penile arteries from pre-diabetic, obese Zucker rats (OZR). EXPERIMENTAL APPROACH:Penile arteries from OZR and from lean Zucker rats (LZR) were ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2009.00553.x
更新日期:2010-02-01 00:00:00
abstract::1. A crude preparation of toxin was extracted from a sample of mussels Mytilus edulis, part of a batch responsible for many cases of paralytic shellfish poisoning.2. The crude extract was partially purified by absorption on sodium Amberlite ion-exchange resin. Two toxins were recovered by elution from the Amberlite, a...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1970.tb10660.x
更新日期:1970-12-01 00:00:00
abstract::1. The pharmacokinetics of cyclophosphamide were investigated in cancer patients. The data can be characterized by a two-compartment open model. The half life of the elimination phase of the drug ranged between 3 and 11 hours.2. Extensive tubular reabsorption of the drug resulted in the excretion of only a small perce...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1971.tb07199.x
更新日期:1971-11-01 00:00:00
abstract:BACKGROUND AND PURPOSE:This study investigated the role of central sympathetic activity and related mitogen-activated protein kinase (MAPK) signalling in the cardiovascular effects of ethanol in a model of acute renal failure (ARF). EXPERIMENTAL APPROACH:The effects of pharmacological interventions that inhibit periph...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2009.00444.x
更新日期:2009-11-01 00:00:00
abstract::1. alpha 1-Adrenoceptor densities were studied in cardiac membrane preparations from several mammalian species including human failing hearts under identical experiment conditions; the alpha 1-adrenoceptor antagonist, [3H]-prazosin, was used as radioligand. End-stage heart failure (NYHA IV) in human hearts was due to ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb14484.x
更新日期:1992-09-01 00:00:00
abstract::Irritable bowel syndrome is characterized by visceral hyperalgesia commonly associated with stress and inflammatory processes. We investigated the role of tachykinin NK2 receptors in the ability of trinitrobenzenesulphonic acid (TNBS) and stress to enhance the sensitivity of the rat rectum to distension using a select...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703040
更新日期:2000-01-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Methylene blue (MB) is commonly employed as a treatment for methaemoglobinaemia, malaria and vasoplegic shock. An increasing number of studies indicate that MB can cause 5-HT toxicity when administered with a 5-HT reuptake inhibitor. MB is a potent inhibitor of monoamine oxidases, but other targe...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2011.01462.x
更新日期:2012-05-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Allosteric modulators of ionotropic receptors and GPCRs might constitute valuable therapeutic tools for intervention in several diseases, including Parkinson's disease (PD). However, the possibility that some of these compounds could alter neurotransmission in health and disease has not been thor...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12758
更新日期:2014-08-01 00:00:00
abstract::The vasorelaxant activity of eicosapentaenoic acid (EPA, 20:5n-3), the omega-3 polyunsaturated fatty acid, was investigated in isolated Wistar Kyoto (WKY) rat aortae by measuring isometric tension. Eicosapentaenoic acid (1 - 100 microM) relaxed rat aortae contracted with high K(+) (80 mM) or noradrenaline (NA, 1 micro...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703754
更新日期:2000-12-01 00:00:00
abstract::1. A study has been made of the effects of cocaine and sympathetic denervation on responses of the cat spleen to (-)-noradrenaline and (-)-isoprenaline.2. Responses of isolated strips of spleen capsule to (-)-noradrenaline or to (-)-isoprenaline were not affected by reserpine-pretreatment.3. In adult cats, cocaine (1 ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1973.tb08255.x
更新日期:1973-08-01 00:00:00
abstract::1. The mechanisms by which nicorandil causes relaxation of rat isolated small mesenteric arteries mounted on a Mulvany myograph was investigated by use of a combination of putatively mechanism-specific antagonists. 2. In arteries precontracted by the thromboxane-mimetic, U46619, the EC50 for cromakalim and levcromakal...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb16071.x
更新日期:1996-12-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Quercetin lowers plasma glucose, normalizes glucose tolerance tests and preserves pancreatic β-cell integrity in diabetic rats. However, its mechanism of action has never been explored in insulin-secreting β-cells. Using the INS-1 β-cell line, the effects of quercetin were determined on glucose- ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2010.00910.x
更新日期:2010-10-01 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::In perfused rabbit adrenal glands, colchicine (500 muM) inhibited the catecholamine secretion evoked by acetylcholine (20 mug/ml) but not that evoked by excess potassium (60 mM). Since both stimuli are believed to release catecholamines ultimately by the same secretory process, exocytosis, it is concluded that these i...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:
更新日期:1972-05-01 00:00:00
abstract::The mechanism of the long duration of action of salmeterol at beta(2)-adrenoceptors has long been a matter of debate, and is still unresolved. Szczuka and colleagues have both summarized the position to date and suggested a new mechanistic contender, receptor rebinding. Despite this, they still do not come to any clea...
journal_title:British journal of pharmacology
pub_type: 评论,杂志文章,评审
doi:10.1111/j.1476-5381.2009.00370.x
更新日期:2009-09-01 00:00:00
abstract::1. We have investigated the effects of chlorpheniramine, atropine and capsaicin pretreatment on inhaled sodium metabisulphite (MBS)-induced airway microvascular leakage and bronchoconstriction in anaesthetized guinea-pigs in order to clarify the mechanisms involved in these responses. The effects of frusemide and nedo...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb12771.x
更新日期:1992-10-01 00:00:00
abstract::1. We have characterized the 5-hydroxytryptamine (5-HT)-induced calcium signalling in endothelial cells from the human pulmonary artery. Using RT-PCR we show, that of all cloned G-protein coupled 5-HT receptors, these cells express only 5-HT1D beta, 5-HT2B and little 5-HT4 receptor mRNA. 2. In endothelial cells 5-HT i...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb16700.x
更新日期:1996-03-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Memantine and ketamine are clinically used, open-channel blockers of NMDA receptors exhibiting remarkable pharmacodynamic similarities despite strikingly different clinical profiles. Although NMDA channel gating constitutes an important difference between memantine and ketamine, it is unclear how...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.13007
更新日期:2015-03-01 00:00:00
abstract::1. Conscious, Long Evans rats (n = 10), chronically instrumented for the measurement of regional haemodynamics, were studied on 3 consecutive experimental days to assess responses to angiotensin II (AII) (125 pmol kg-1, i.v.) and noradrenaline (1 nmol kg-1, i.v.) in the absence and presence of the AT2-receptor antagon...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb14540.x
更新日期:1992-11-01 00:00:00
abstract::Previous studies have provided evidence for the presence on B cell membrane of adenosine receptors (P1-purinoceptors) of the A1-subtype which inhibit insulin secretion. In this work we have investigated the implication of a guanosine triphosphate (GTP) binding protein (G protein) in the A1 purinoceptor-induced inhibit...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1989.tb11775.x
更新日期:1989-01-01 00:00:00
abstract::1. Human epicardial coronary artery rings, freshly obtained from cardiac transplant patients, were examined for their responses to endothelium-derived relaxing factor (EDRF)-releasing agents. 2. Functional antagonism profoundly influenced relaxation responses in this tissue. Increasing force with concentrations of U46...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1994.tb17109.x
更新日期:1994-12-01 00:00:00
abstract::1. Vasospasm of arterial conduits used for coronary artery surgery is an important cause of graft failure and is likely to result partly from raised levels of vasoconstrictor substances such as thromboxane A(2) and endothelin-1. Our aim was to find pharmacological agents that could prevent agonist-induced vasospasm. 2...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703809
更新日期:2001-01-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Pancreatic cancer is characterized by alterations in several key signalling proteins, including increased expression and activity of the Src tyrosine kinase and focal adhesion kinase (FAK), which have been linked to its chemoresistance. Sustained Src inhibition reactivates survival pathways regul...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/bph.12855
更新日期:2015-01-01 00:00:00
abstract::1. The effects of seven agonist and three antagonist adenosine receptor ligands were compared on the guinea-pig sinoatrial (SA) node (isolated right atrium) and atrioventricular (AV) node (perfused whole heart). Single agonist concentration-effect curves were obtained to 5'-N-ethylcarboxamidoadenosine (NECA), R(-)-N6-...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0701891
更新日期:1998-06-01 00:00:00