葛根素对大鼠心室肌细胞动作电位的影响

目的:从电生理角度探讨葛根素抗心律失常的可能机制。方法:采用膜片钳技术记录大鼠心室肌细胞动作电位(AP)、转染的人胚胎肾细胞缓慢延迟整流钾电流(IKs),观察加药前、后葛根素对AP和IKs的影响。结果:0.01、0.1、1 mmol/L葛根素可浓度依赖性地延长动作电位时程,分别使APD50从(71.8±11.8)ms延长至(86.9±10.7)ms、(100.5±14.1)ms和(123.6±25.4)ms;使APD90从(164.6±21.4)ms延长至(188.3±11.5)ms、(221.6±25.7)ms和(278.7±38.2)ms(n=6,均P0.05),而对RMP、APA和APD20无显著影响。此外,0.01、0.1、1 mmol/L葛根素对IKs抑制率分别为(17.8±2.5)%、(40.4±1.9)%和(60.9±3.2)%(n=6,均P0.05)。结论:葛根素可能通过抑制IKs来延长动作电位时程,发挥抗心律失常作用。

Effects of Puerarin on Action Potential of Ventricular Myocytes of Rats

Objective:To investigate the antiarrhythmic effect of puerarin and the possible mechanism by electrophysiological method.Methods:The action potential (AP) and the slow delayed rectifier potassium current (IKs) were respectively observed in rat ventricular myocytes and transfected human embryonic kidney 293T cells before and after administration of puerarin by patch clamp technique.Results:0.01, 0.1, 1 mmol/L of puerarin remarkably prolonged action potential duration (APD) in a concentration dependent manner. Puerarin (0.01, 0.1, 1 mmol/L) augmented APD50 from (71.8± 11.8) ms to (86.9 ± 10.7) ms, (100.5± 14.1) ms and (123.6± 25.4) ms, as well as APD90, from (164.6± 21.4) ms to (188.3± 11.5) ms, (221.6± 25.7) ms and (278.7± 38.2) ms respectively (n=6, all P<0.05), while it had no significant effect on RMP, APA and APD20. Additionally, puerarin (0.01, 0.1, 1 mmol/L) inhibited IKs by 17.8± 2.5%, 40.4± 1.9% and 60.9± 3.2%, respectively (n=6, all P<0.05).Conclusion:Puerarin apparently extends APD via inhibitting IKs, which could underline its electrophysiological basis of anti-arrhythmic mechanisms.