牛磺酸对豚鼠乳头状肌慢反应动作电位的影响(英文)

Effects of taurine on slow action potentials in papillary muscles of guinea pig

目的:研究牛磺酸对豚鼠乳头状肌慢反应动作电位的影响.方法:高钾(24 mmol·L^(-1))或河豚毒素(40 μmol·L^(-1))诱发慢反应动作电位.哇巴因诱发振荡后电位.结果:牛磺酸(20mmol·L^(-1))减少V_(max),延长APD_(50)并拮抗氯化钙(3 mmol·L^(-1))增加APA和V_(max)及缩短APD的作用,增加哇巴因诱发OAP所需浓度并延长其发生时间.

AIM: To examine the effects of taurine on the slow action potentials induced by KC1 24 mmol .L-1 or tetrodotoxin 40umol.L-1 in guinea pig papillary muscles. METHODS: The transmembrane AP was recorded by a conventional glass microelectrode filled with KC1 3 mmol.L-1. The muscles were exposed to high K+-Tyrode's solution or perfused with Tyrode's solution containing tetrodotoxin. Ouabain was added in order to induce oscillatory afterpotentials. RESULTS: Taurine 20 mmol.L-1 decreased the maximal upstroke velocity of slow action potential and prolonged the action potential duration at 50 % of repo-larization. The amplitude of slow action potential and the maximal upstroke velocity both increased by CaCl23 mmol.L-1 were antagonized by taurine. Taurine increased the concentration of ouabain for oscillatory afterpo-tential and prolonged the onset time of oscillatory afterpotential. CONCLUSION:Taurine possesses a calcium antagonistic property.