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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200.0mmol/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12.5mmol/L的乙醇对心房肌细胞AP各参数无明显影响;25.0～200.0mmol/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200.0mmol/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)。6.25～25.0mmol/L的乙醇对心室乳头状肌细胞AP各参数无明显影响;50.0～200.0mmol/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200.0mmol/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,6.25～200.0mmol/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12.5mmol/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50.0～200.0mmol/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。
In order to study the effect of ethanol on myocardial action potential and its mechanism, we used standard glass microelectrode intracellular recording technique to record the action potential (AP) of isolated rat cardiomyocytes. Whole-cell patch-clamp technique was used to record HEK293 cells (Human Kv1.5, hKv1.5) channel currents, to observe the effects of 6.25, 12.5, 25.0, 50.0, 100.0 and 200.0 mmol / L ethanol on isolated rat atrial and ventricular papillary muscle cells AP parameters of the changes and Kv1.5 channel current. The results showed that there was no significant effect of 6.25 and 12.5mmol / L ethanol on AP parameters of atrial myocytes; 25.0 ~ 200.0mmol / L ethanol could cause the action potential duration (APD), AP complex The action potential duration of 50% repolarization (APD50) and APD90 (90% repolarization, APD90) were significantly prolonged (P <0.05 or P <0.01) ; And 100.0 and 200.0mmol / L of ethanol can also make the action potential amplitude (APA) of atrial myocytes decreased (P <0.05 or P <0.01). 6.25 ~ 25.0mmol / L ethanol had no effect on AP parameters of atrial papillary myocytes; 50.0 ~ 200.0mmol / L ethanol caused a significant prolongation of APD, APD50 and APD90 in atrial papillary myocytes (P <0.05 or P <0.01). Moreover, ethanol (200.0 mmol / L) also decreased the APA of papillary muscle cells (P <0.05). Whole-cell patch clamp results showed that 6.25 ~ 200.0mmol / L of ethanol concentration-dependent inhibition of Kv1.5 channel current. The above results show that 6.25 and 12.5mmol / L ethanol on rat atrial and ventricular papillary muscle AP parameters had no significant effect, while 50.0 ~ 200.0mmol / L ethanol can significantly prolong the isolated rat atrial and ventricular papillary Muscular APD, the mechanism may be related to inhibition of Kv1.5 channel current.