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兔肺静脉肌袖心肌细胞动作电位的特性和一些离子流机制

丁怀玉, 杨新春, 刘秀兰, 刘泰摓, 鲍荣凤

首都医科大学附属北京朝阳医院心脏中心.北京 100020

摘要

研究兔肺静脉肌袖心肌细胞（cardiomyocytes from rabbit pulmonary vein sleeves, PVC）动作电位的特性和一些离子流机制-----内向整流钾电流（I_(Kl)）、瞬时外向钾电流（I_(To)）和非选择性阳离子流（I_(NSCC)），并与左心房心肌细胞（left atrial cardiomyocytes，LAC）进行比较。采用全细胞膜片钳技术，记录动作电位和上述各离子流。发现PVC动作电位时程（action potential duration，APD）较LAC的明显延长，并可以诱发出第二平台反应。PVC上存在I_(NSCC)。 PVC的I_(Kl)、I_(To)和I_(NSCC)电流密度均较LAC的明显减小。PVC和LAC存在复极离子流的差异，这种差异构成了两者动作电位差异的基础，进而可能成为肺静脉肌袖致心律失常特性的重要离子流机制。

关键词： 兔; 肺静脉; 动作电位; 离子通道

Characteristics of the action potentials and the underlying ionic mechanisms in the cardiomyocytes from rabbit pulmonary vein sleeves

Ding Huaiyu, Yang Xinchun, Liu Xiulan, Liu Taifeng, Bao Rongfeng

Heart Center, Beijing Chaoyang Hospital Affiliated to the Capital University of Medical Sciences.Beijing 100020

Abstract

To investigate the characteristics of action potentials and their ionic mechanism in cardiomyocytes from rabbit pulmonary vein sleeves （PVC）, and to compare them with those in left atrial cardiomyocytes （LAC）, the technique of whole-cell patch clamp was applied. We used current-clamp technique to record action potentials, and voltage-clamp technique to record ionic currents. PVC had longer action potential duration （APD） than LAC, and therefore a second plateau response could be induced easily, suggesting a strong tendency of early afterdepolarization （EAD） genesis in PVC. Non-selective cation current （I_(NSCC)） was first recorded in both LAC and PVC. This I_(NSCC) was permeable to K~(+), Na~(+) and Cs~(+), sensitive to GdCl_(3) but not sensitive to 4-AP. The current densities of inward rectifier potassium current （I_(Kl)）, transient outward potassium current （I_(To)） and I_(NSCC) were all significantly less in PVC than those in LAC. These differences in repolarizing ionic currents between PVC and LAC form a basis of the differences in their action potential configurations and might be an important ionic mechanism of the arrhythmogenic characteristics of pulmonary vein muscle sleeves.

Key words: Rabbit;pulmonary veins;Action potentials;ionic channels

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引用本文：

丁怀玉, 杨新春, 刘秀兰, 刘泰摓, 鲍荣凤. 兔肺静脉肌袖心肌细胞动作电位的特性和一些离子流机制[J]. 生理学报 2006; 58 (2): .

Ding Huaiyu, Yang Xinchun, Liu Xiulan, Liu Taifeng, Bao Rongfeng. Characteristics of the action potentials and the underlying ionic mechanisms in the cardiomyocytes from rabbit pulmonary vein sleeves. Acta Physiol Sin 2006; 58 (2): (in Chinese with English abstract).