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小鼠心室肌细胞外向电流的特征分析

周军, 郝雪梅, 王忠民, 金满文, 钱家庆, 刘泰Feng

北京大学生物膜与膜生物工程国家重点实验室. 北京 100871；同济医科大学基础医学院. 湖北, 武汉430030

摘要

用全细胞膜片箝技术研究了小鼠心室肌细胞去极化激活的非钙依赖性外向电流的特征 。短时去极化至—50mv以上电位可引发快速上升的外向钾电流, 之后缓慢衰减至一平台 。在改变保持电位时, 该峰电流与平台电流的比值也发生改变。外向电流的衰减过程可 用双指数方式很好拟合, 而在500ms预脉冲刺激后再经去极化刺激的电流时程适合单指 数方式。

关键词： 钾通道; 电生理学; 心脏; 小鼠; 全细胞膜片箝技术

Characterization of outward current in mouse ventricular myocytes

Zhou Jun, Hao Xuemei, Wang Zhongmin, Jin Manwen, Qian Jiaqing, Liu Taifeng

National Key Laboratory of Biomembrane and Membrane Bioengineering, College of Biosciences, Peking University. Beijing 100871； China

Abstract

During brief depotarizations to potentials positive to-50mV, outward K~(+) currents in these cells rise rapidly to a peak followed by a slower decay to an apparent plateau. The relative peak to plateau amplitudes in a single cell varied as a function of the holding potential (HP) from which the currents were evoked. Reversal potentials for the peak and plateau components were -64.3±3.9mV and -53.3±2.9mV, respectively(uncorrected for junction potentials). The outward current decay is well described by double exponential fits, whereas the time course of peak I_(out) decay following a 500 ms prepulse is best fitted by single exponential function, indicating the presence of two distinct components, I_(kf) and I_(ks), of the outward currents in mouse ventricular cells. Application of 4-AP were accompanied by a marked attenuation of peak I_(out) and plateau I_(out), indicating that both I_(kf) and I_(ks) display similar sensitivities to 4-AP.

Key words: Potassium channel;Electrophysiology;Heart;Mouse;Whole-cell patch-clamp technique

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引用本文：

周军, 郝雪梅, 王忠民, 金满文, 钱家庆, 刘泰Feng. 小鼠心室肌细胞外向电流的特征分析[J]. 生理学报 1995; 47 (6): .

Zhou Jun, Hao Xuemei, Wang Zhongmin, Jin Manwen, Qian Jiaqing, Liu Taifeng. Characterization of outward current in mouse ventricular myocytes. Acta Physiol Sin 1995; 47 (6): (in Chinese with English abstract).