乙醇对兔心室肌细胞L-型钙离子通道电流的影响

Effects of ethanol on L-type calcium channel current in rabbit ventricular myocytes

【目的】观察乙醇对兔心室肌细胞L-型钙离子通道电流(ICa,L)的影响。【方法】采用蛋白酶消化的成年兔单个心室肌细胞及膜片钳全细胞技术,记录不同浓度乙醇对ICa,L的作用。【结果】(1)乙醇抑制ICa,L峰值,24 mmol/L和240 mmol/L乙醇抑制率差异有统计学意义(P<0.05)。(2)24、80、240 mmol/L乙醇使ICa,L的电流-电压(I-V)曲线上移,在各测试电压下,电流均减小,但不影响曲线形状,用乙醇后最大激活电压仍在0mV左右。【结论】致毒浓度(24 mmol/L)的乙醇对ICa,L具有明显抑制作用。可导致心肌产生负性肌力作用,动作电位时程缩短,诱发心律失常。

[Objective] To study the effects of ethanol at different concentration on L-type calcium channel current （ICa,L） t in rabbit ventricular myocytes. [Methods] Using whole-cell patch-clamp technique in isolated rabbit ventricular myocytes with an enzymatic procedure, IC.,L was recorded before and after application of different concentration of ethanol respec- tively. [Results] （1） Ethanol, 24 mmol/L reduced the peak current of ICa,L. The difference of percentage of inhibition of ethanol between 240 mmol/L and 24 mmol/L was significant （P 〈 0.05）. （2） Ethanol of 24, 80 and 240 mmol/L shifted the I-V curve of Ica,L upward. The contour of I-V curve kept unchanged, and the peak current induced voltage remained at 0mV. [Conclusions] Ethanol may inhibite ICa,L at clinically relevant concentration （24 mmol/L）, contribute to a negative inotropic effect, shortening the action potential duration and induce arrhythmias.