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

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

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。

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 （ APD90 ） 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 APDg0 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 vohage 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 significam 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.