大蒜素对小鼠心房肌细胞多种钾电流的阻滞效应

Blocking effects of allicin on various potassium currents in mouse atrial myocytes

目的 探讨大蒜素对小鼠心房肌细胞多种钾电流的作用及其机制。方法 采取双酶消化法将单个小鼠心房肌细胞分离出来,灌流法将药物作用于细胞,采用全细胞膜片钳技术,分别记录心房肌细胞的外向钾电流(I_(K,peak))、瞬时外向钾电流(I_(to))和超极化激活延迟整流钾电流(I_(KUr))。结果 钳制电压在+70 mV时,30μmol/L大蒜素可使小鼠心房肌细胞I_(K,peak)、I_(to)和I_(KUr)峰值显著降低,对I_(to)表现出抑制作用,该作用还呈现出一定的浓度依赖性和电压依赖性,半数抑制浓度(IC_(50))为(21.0±3.8)μmol/L。深入研究门控机制结果显示,I_(to)通道稳态失活曲线在大蒜素的作用下发生左移,且失活后再次激活的时间有所延迟,对于通道的关闭态失活过程影响不大,提示大蒜素主要通过抑制通道稳态失活和失活后恢复过程,减少I_(to)电流密度,同时对I_(KUr)也有阻滞作用,进而导致对总的外向电流抑制。结论 大蒜素可以直接降低小鼠心房肌细胞多种钾电流,这为进一步应用于房性心律失常提供潜在的可能。

Objective To study the effect of allicin on various potassium currents in mouse atrial myocytes and its action mechanism.Methods The double-enzyme digestion method was used to isolate a single mouse atrial myocyte,and the perfusion method was used to administer the drug to cells.The whole-cell patch clamp technique was used to record the outward potassium current(I_(K,peak)),the transient outward potassium current(I_(to))and hyperpolarization activated delayed rectifier potassium current(I_(KUr))in atrial myocytes,respectively.Results In presence of 30μmol/L allicin,the peak current of I_(K,peak),I_(Kur) and I_(to) in mice artial myocytes were all significantly reduced at the clamping voltage of+70 mV,and showed inhibitory effect on I_(to) in a concentration-and voltage-dependent way,with half inhibitory concentration(IC_(50))was(21.0±3.8)μmol/L.Further studies on the gating mechanism showed that the steady-state inactivation curve of the I_(to) was shifted to the left by allicin,and the reactivation time was delayed after inactivation,but had little effect on the closed-state inactivation of the channel.It was suggested that allicin could mainly inhibit the steady-state inactivation of the channel and the recovery process after inactivation to reduce the I_(to) current density,and also has a blocking effect on I_(Kur),which lead to the inhibition of the total outward currents.Conclusions Allicin could directly reduce a variety of potassium currents in mouse atrial myocytes,which provide potential for further application in atrial arrhythmia.