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乙醇对大鼠心肌动作电位及人Kv1.5通道的影响

胡浩, 周筠, 孙强, 于晓江, 张宏丽, 马欣, 刘传镐, 臧伟进^*

西安交通大学医学院药理学系，西安 710061

摘要

为了研究乙醇对心肌动作电位的作用及其机制，本实验采用标准玻璃微电极细胞内记录技术记录离体大鼠心肌细胞的动作电位(action potential, AP)，采用全细胞膜片钳技术记录HEK293细胞上表达的人Kv1.5 (human Kv1.5, hKv1.5)通道电流，观察6.25、12.5、25.0、50.0、100.0及200.0 mmol/L的乙醇对离体大鼠心房肌和心室乳头状肌细胞AP各参数的改变及对Kv1.5通道电流的影响。结果显示，6.25和12.5 mmol/L的乙醇对心房肌细胞AP各参数无明显影响；25.0~200.0 mmol/L的乙醇可引起心房肌细胞的动作电位时程(action potential duration, APD)、AP复极至50%的时程(action potential duration of 50% repolarization, APD50)及AP复极至90%的时程(action potential duration of 90% repolarization, APD90)明显延长(P < 0.05或P < 0.01)；而且100.0和200.0 mmol/L的乙醇还可使心房肌细胞的动作电位幅值(action potential amplitude, APA)降低(P < 0.05或P < 0.01)。6.25~25.0 mmol/L的乙醇对心室乳头状肌细胞AP各参数无明显影响；50.0~200.0 mmol/L的乙醇可引起心室乳头状肌细胞的APD、APD50及APD90明显延长(P < 0.05或P < 0.01)；而且200.0 mmol/L的乙醇还可使心室乳头状肌细胞的APA降低(P < 0.05)。全细胞膜片钳结果显示，6.25~200.0 mmol/L的乙醇可浓度依赖性地抑制Kv1.5通道电流。以上结果表明，6.25和12.5 mmol/L乙醇对离体大鼠心房肌、心室乳头状肌AP各参数无明显影响，而50.0~200.0 mmol/L乙醇可明显延长离体大鼠心房肌、心室乳头状肌APD，其作用机制可能与抑制Kv1.5通道电流有关。

关键词： 乙醇; 心肌; 动作电位时程; Kv1.5通道

分类号：R3

[Effects of ethanol on action potential of rat myocardium and human Kv1.5 channel.] [Article in Chinese]

HU Hao, ZHOU Jun, SUN Qiang, YU Xiao-Jiang, ZHANG Hong-Li, MA Xin, LIU Chuan-Hao, ZANG Wei-Jin^*

Department of Pharmacology, School of Medicine, Xi’an Jiaotong University, Xi’an 710061, China

Abstract

The purpose of the present study was to investigate the effects of different concentrations of ethanol on action potential (AP) in the isolated rat myocardium and the possible mechanism of electric-physiological changes. Standard microelectrode technique was used to record AP in isolated rat myocardium, and whole cell patch clamp technique was used to record the human Kv1.5 (hKv1.5) channel currents in HEK293 cells. The effects of different concentrations of ethanol (6.25, 12.5, 25.0, 50.0, 100.0 and 200.0 mmol/L) on AP parameters in rat atrium and papillary and Kv1.5 channel currents in HEK293 cells were analyzed. The results showed that in isolated atrium, action potential amplitude (APA), action potential duration (APD), action potential duration of 50% repolarization (APD50) and action potential duration of 90% repolarization (APD90) were not affected by 6.25 and 12.5 mmol/L ethanol, while APD, APD50 and APD90 were prolonged significantly by 25.0–200.0 mmol/L ethanol (P < 0.05 or P < 0.01), and APA was reduced with 100.0 and 200.0 mmol/L ethanol (P < 0.05 or P < 0.01). In isolated papillary, APA, APD, APD50 and APD90 were not affected by 6.25–25.0 mmol/L ethanol, while APD, APD50 and APD90 were prolonged significantly with 50.0–200.0 mmol/L ethanol (P < 0.05 or P < 0.01), and APA was reduced with 200.0 mmol/L ethanol (P < 0.05). The Kv1.5 channel currents were inhibited by ethanol in a concentration dependent manner in HEK293 cells. These findings suggest that 6.25 and 12.5 mmol/L ethanol produce no effects on AP parameters, and 50.0–200.0 mmol/L ethanol prolong APD significantly in isolated rat atrium and papillary. The prolonged effect on APD in isolated myocardium may be due to the inhibition of the Kv1.5 channel currents.

Key words: Ethanol; myocardium; action potential duration; Kv1.5 channel

收稿日期：2011-01-13　　录用日期：2011-04-07

通讯作者：臧伟进　　E-mail: zwj@mail.xjtu.edu.cn

引用本文：

胡浩, 周筠, 孙强, 于晓江, 张宏丽, 马欣, 刘传镐, 臧伟进. 乙醇对大鼠心肌动作电位及人Kv1.5通道的影响[J]. 生理学报 2011; 63 (3): 219-224.

HU Hao, ZHOU Jun, SUN Qiang, YU Xiao-Jiang, ZHANG Hong-Li, MA Xin, LIU Chuan-Hao, ZANG Wei-Jin. [Effects of ethanol on action potential of rat myocardium and human Kv1.5 channel.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (3): 219-224 (in Chinese with English abstract).