Prejunctionally mediated inhibition of neurotransmission by isoprenaline in rat vas deferens
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摘要Effects of isoprenaline on monophasic contractions evoked by electric field stimulation were studied in rat isolated prostatic vas deferens. Isoprenaline reduced electrically evoked contractions (EC50: 0.27 +/- 0.05 mu M), and propranolol concentration-dependently antagonized the effect of isoprenaline. In contrast, isoprenaline (0.3-3 mu M) did not affect the contractile response induced by exogenous noradrenaline or ATP, while forskolin (100 nM) attenuated agonist-induced contraction. In some tissues, adrenergic and purinergic components of the electrically evoked contraction were isolated by exposure to alpha,beta-methylene ATP (3 mu M) and prazosin (3 mu M), respectively. Isoprenaline induced a greater inhibition of purinergic than adrenergic component of the electrically evoked contraction. Iberiotoxin (50 nM), glibenclamide (3 mu M), 4-aminopyridine (0.3 mM) and tetraethylammonium ions (1 mM) attenuated the effect of isoprenaline. These results indicate that isoprenaline-induced inhibition of the electrically evoked (both purinergic and adrenergic) contraction was mediated primarily through activation of prejunctional beta-adrenoceptors, which probably inhibited release of contractile transmitters from sympathetic nerves supplying vas deferens. Lack of effect of isoprenaline on agonist-induced contraction does not favour a functional role of beta-adrenoceptors in vas smooth muscle.
著者Huang Y, Lau CW, Chan NWK, Yao XQ, Chan FL
期刊名稱Life Sciences
出版年份1998
月份10
日期30
卷號63
期次23
出版社PERGAMON-ELSEVIER SCIENCE LTD
頁次2107 - 2113
國際標準期刊號0024-3205
電子國際標準期刊號1879-0631
語言英式英語
關鍵詞field stimulation; isoprenaline; K+ channels; neurotransmission; propranolol; vas deferens
Web of Science 學科類別Medicine, Research & Experimental; MEDICINE, RESEARCH & EXPERIMENTAL; Pharmacology & Pharmacy; PHARMACOLOGY & PHARMACY; Research & Experimental Medicine

上次更新時間 2020-14-10 於 01:21