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游离心肌细胞晚钠通道爆发型开放模式的电位依赖性

刘远谋, 王红卫, 李慈珍

上海第二医科大学生理教研室. 上海 200025

摘要

应用膜片箝技术记录豚鼠游离心室肌细胞钠通道电流，发现除极可引起晚钠电流爆发型开放，而复极可终止爆发型活动。爆发型模式的通道电流不仅有浓度依赖性和电位依赖性，其升放时间常数也随箝制电位变正而增大。多步阶梯式除极和叙线除极的实验结果首次表明电位变化愈迅速、除极步数愈多，爆发型出现的机率也就愈高。

关键词： 游离心室肌细胞; 膜片箝; 晚钠电流; 模式; 爆发型

Voltage dependence of late Na channel with burst mode in isolated cardiac myocytes

Liu Yuanmou, Wang Hongwei, Li Cizhen

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

Abstract

Patch clamp technique was employed to record single Na channel currents in isolated guinea-pig ventricular myocytes. Burst mode could be elicited by step depolarization and terminates immediately after repolarization. The unitary current of burst mode was not only dependent on Na concentration in the pipettes but also on the test voltage. The open time constant increased as testing voltage hecomes more positive. The results from stepwise-depolarization and ramp depolarization experiments showed that the more steps or the faster the upstroke velocity of depolarization used, the more the burst mode would occure.

Key words: Isolated ventricular myocytes;Patch clamp;Late Na current;Mode;Burst

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引用本文：

刘远谋, 王红卫, 李慈珍. 游离心肌细胞晚钠通道爆发型开放模式的电位依赖性 [J]. 生理学报 1997; 49 (5): .

Liu Yuanmou, Wang Hongwei, Li Cizhen. Voltage dependence of late Na channel with burst mode in isolated cardiac myocytes. Acta Physiol Sin 1997; 49 (5): (in Chinese with English abstract).