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微电极矩阵研究小鼠胚胎心脏电生理活动

段亚琦, 唐明, 梁华敏, JÜrgen Hescheler

华中科技大学同济医学院生理学系，卫生部肺疾病实验室. 湖北，武汉430030；德国科隆大学神经生理学系. 科隆D-50931

摘要

该实验采用一种新方法-----微电极矩阵技术从整体水平研究小鼠胚胎离体整体心脏电生理活动。作者用微电极矩阵记录与60个电极相接触的心肌细胞的电活动(细胞外记录)，称为场电位(field potentials, FPs)，并与全细胞膜片钳记录的动作电位(action potentials, APs)(细胞内记录)进行比较，发现心房、心室处场电位形态类似于负向的细胞动作电位，场电位时程亦与动作电位时程类似。为研究兴奋的传导，作者比较了不同电极处场电位发生时间，发现在房室结构还未形成的胚胎发育d9.5(E9.5)已经观察到明显的房室传导延迟(A--V delay) [(50.21±9.7) ms]，而心室不同部位兴奋几乎是同步的。在发育晚期(E16.5)，房室传导延迟为(82.21±10.50) ms。进一步研究基本的神经体液因素对心脏兴奋的调控，表明：在E9.5，异丙肾上腺素(isoproterenol，Iso)使胚胎兴奋频率加快(34.04±7.31)%，房室传导延迟缩短(20.00±6.44)%，同时场电位时程增宽；相反，卡巴唑(carbachol, CCh) 则使兴奋频率降低(42.32±5.36)%，房室传导缩短(26.00±4.81)%，场电位时程减小。 而在E16.5，Iso的作用显著增强，兴奋频率加快(101.54±10.23)%，房室传导延迟缩短(56.62±6.43)%，而CCh则几乎使所有晚期心脏兴奋完全消失。所以，心脏的传导系统在胚胎发育早期4个腔室还未形成时已经建立，神经体液因子对心脏基本电生理活动的调控是在发育过程中逐渐成熟的。

关键词： 微电极记录; 场电位; 动作电位

Investigation on spontaneous electrical activity of murine embryonic heart using microelectrode arrays

Duan Yaqi, Tang Ming, Liang Huamin, JÜrgen Hescheler

Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Pulmonary Disease Laboratory of Ministry of Health of China. Wuhan 430030, China；Institute of Neurophysiology, University of Cologne, Cologne D-50931, Germany

Abstract

In our studies, we have applied a novel tool----microelectrode arrays (MEA), to investigate the electrophysiological properties of murine embryonic hearts in vitro. The electrical signals were recorded from the areas of the heart adhering to the 60 MEA electrodes, being called field potentials (FPs). As an extracelluar recording, the waveform of the FP appeared similar to a reversed action potential obtained from single cell by whole cell current clamp and the FP duration was comparable with the action potential duration. To study propagation of spontaneous electrical activity, we have compared the occurrence time of FPs recorded from different electrodes. It is shown that there was already an apparent A-V delay [(50.21±9.7) ms] at day 9.5 post coitum (E9.5) when heart was still tubular-like and atrium and ventricle were not separated anatomically, while occurence of FP at different electrodes of ventricular area were almost synchronous. Further, we looked into the modulation of spontaneous electrical activity during cardiac development: at E9.5 of embryonic development, 1 #mu#mol/L of isoproterenol (Iso) increased beating frequency by (34.04±7.31)%, shortened the A-V delay by (20.00±6.44)% and prolonged FP duration. In contrast, 1 #mu#mol/L of carbachol (CCh) slowed down beating frequency by (42.32±5.36)%, A-V conduction by (26.00±4.81)% and shortened FP duration; however at late stage (E16.5), the regulatory effect of Iso and CCh was strengthened. Therefore we conclude that cardiac conduction system is already established at E9.5 when the four-chambered heart is not formed yet and the regulation of spontaneous activity by sympathetic and para-sympathetic system is gradually matured during cardiac development.

Key words: Microelectrode arrays;Field potential;Action potential

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引用本文：

段亚琦, 唐明, 梁华敏, JÜrgen Hescheler. 微电极矩阵研究小鼠胚胎心脏电生理活动[J]. 生理学报 2006; 58 (1): .

Duan Yaqi, Tang Ming, Liang Huamin, JÜrgen Hescheler. Investigation on spontaneous electrical activity of murine embryonic heart using microelectrode arrays. Acta Physiol Sin 2006; 58 (1): (in Chinese with English abstract).