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溶血磷脂酰胆碱对缺血条件下羊浦肯野纤维I_(f)电流的影响

胡优敏, 张照, 高汝驫, 徐有秋

上海第二医科大学生理教研室. 上海 200025

摘要

该文用双微电极电压箝制术观察“缺血”及毒性代谢产物溶血磷脂酸胆碱(LPC)对绵羊心室浦肯野纤维起搏离子流I_(f)的影响。用模拟缺血溶液灌流15，30和60min后，在-60mV～120mV之间的各不同指令电位水平I_(f)离子流幅值均降低(n=5，P＜0.05)，激活达稳态时间及半激活时间延长(n=5，P＜0.05)，稳态激活曲线向超极化方向移位。在正常台氏液中加入2×10~(-5)mol/LIPC，灌流后，各个膜电位水平的浦氏纤维起搏离子流If的幅值显著降低(n=10，P＜0.05)，稳态激活曲线向超极化方向移位，但I_(f)激活达稳态时间及半激活时间均无明显改变。在模拟缺血溶液灌流30min基础上，再加2×10~(-5)mol/LLPC灌流，15min后测得I_(f)幅值进一步减小(n=10，P＜0.05)，加剧了“缺血”对I_(f)离子流的抑制作用。上述结果表明：缺血代谢产物溶血磷脂酸胆碱对心室的正常自律活动具有抑制作用，在模拟缺血条件下，它能使已受抑制的自律活动抑制进一步加深。因此它的存在不会异常增强心室自律性活动而发生快速性室性心律失常。

关键词： 溶血磷脂酰胆碱; 起搏离子流; 心肌缺血

Effect of lysophosphatidylcholine on the pacemaker current I_(f) of sheep cardial purkinje fibers in ischemia-like condition

Hu Youmin, Zhang Zhao, Gao Rubiao, Xu Youqiu

Department of Physiology, Shanghai Second Medical University. Shanghai 200025, China

Abstract

By using two microelectrode voltage clamp technique, the effects of “ischemia” and lysophosphatidylcholine (LPC), a main toxic metaboli te in acute ischendic myocardium,on pacemaker current I_(f) were examined in sheep cardiac Puri nje fibers. Afer perfusion with ischemia-like solution for 15, 30 and 60 min, the amplitude of I_(f) current was decreased at all meInbrane potential levels between -60 mV～-120 mV (n=5, P<0.05), both the activation time and half activation time reaching a steady state value were prolongated (n=5, P<0.05), with a result of shifting activation curve of If to a more hperpolarizing level. In normal Tyrode s0lution, the amplitudes of I_(f) at all measured potential levels were decreased significantly by LPC 2×10~(-5) mol/L (n=10, P<0.05); the steady-state activation curve of I_(f) was shifted to a more hyperpolarizing level but the activation time and half activation time to a steady-state value were not changed.

Key words: Lysophosphatidycholine;Pacemaker current I_(f);Myocardial ischemia

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引用本文：

胡优敏, 张照, 高汝驫, 徐有秋. 溶血磷脂酰胆碱对缺血条件下羊浦肯野纤维I_(f)电流的影响[J]. 生理学报 1997; 49 (5): .

Hu Youmin, Zhang Zhao, Gao Rubiao, Xu Youqiu. Effect of lysophosphatidylcholine on the pacemaker current I_(f) of sheep cardial purkinje fibers in ischemia-like condition. Acta Physiol Sin 1997; 49 (5): (in Chinese with English abstract).