黄芪总黄酮对豚鼠心室肌细胞动作电位和延迟整流钾电流的作用

目的:研究黄芪总黄酮(TFA)对豚鼠心室肌细胞动作电位(AP)和延迟整流钾电流(IK)的作用。方法:实验采用标准玻璃微电极细胞内记录心室肌细胞AP和全细胞膜片钳技术记录IK。结果:应用TFA 20 mg/kg后心室肌AP的幅度从给药前的(70.25±5.97)mV降低到(58.73±4.86)mV(n=6,P<0.05);AP时程(APD90)从给药前的(236.08±17.63)ms延长到(282.13±22.01)ms(n=6,P<0.05)。应用TFA 40 mg/kg后心室肌AP的幅度从给药前的(72.65±5.12)mV降低到(48.32±8.76)mV(n=6,P<0.05);AP时程(APD90)的从给药前的(265.34±14.82)ms延长到(315.46±24.33)ms(n=6,P<0.05)。而应用TFA 20 mg/kg后,在+50 mV指令电压下,心室肌细胞的IK从(1.21±0.24)nA降至(0.96±0.27)nA(n=6P<0.01),应用TFA 40 mg/kg后心室肌细胞的IK从(1.45±0.36)nA下降到(1.01±0.27)nA,差异有显著性(n=6P<0.01)。结论:TFA可以降低心室肌AP幅值,延长AP时程,抑制心室肌细胞的IK幅值,并且有一定的剂量依赖性。

Effects of totalflavonoids of astragalus (TFA) on the action potential and delayde rectifier potassium channel in ventricular myocyte of guinea pig

Objective:To study the effects of Totalflavonoids of Ast ragalus(TFA) on the action potential and the delayed rectifier potassium channel in ventricular myocardium of guinea pig.Method:The action potential and the delayed rectifier potassium current was recorded in guinea pig ventricular myocyte by using of standard microelectrodes and whole cell patch clamp technique.Result:The action potential amplitude(APA) of ventricular myocardium was decreased from(70.25±5.97)mV to(58.73±4.86)mV(n=6,P<0.05),the duration(APD_(90))of ventricular myocardium was expanded from(236.08±17.63)ms to(282.13±22.01)ms(n=6,P<0.05) after application of TFA dosage of 20 mg/kg.The APA of ventricular myocardium was decreased from(72.65±5.12)mV to(48.32±8.76)mV(n=6,P<0.05)and the APD_(90) of ventricular myocardium was prolonged from(265.34±14.82)ms to(315.46±24.33)ms(n=6,P<0.05)after application of TFA dosage of 40 mg/kg.Under the command voltage of 50 mV,IK in TFA dosage of 20 mg/kg decreased from(1.21±0.24)nA to(0.96±0.27) nA.While IK in TFA dosage of 40 mg/kg decreased from (1.45±0.36)nA to(1.01±0.27)nA.There is significant difference between control group(n=6 P<0.01),and application of TFA dosage of 20 mg/kg and 40 mg/kg.Conclusion:It has been suggested that TFA decrease action potential amplitude,prolong action potential duration and inhibit delayed rectifier potassium current of ventricular myocyte in guinea pig remarkably with concentration-dependence.