海葵素对大鼠和豚鼠心室肌细胞钾电流的影响

Effects of anthopleurin-Q on potassium currents of ventricular myocytes in rats and guinea pig

目的:研究海葵素-Q(AP-Q)对心室肌细胞钾电流的作用。方法:采用酶解法制备豚鼠和大鼠单个心室肌单细胞,应用全细胞膜片钳记录方法记录心室肌细胞钾电流(Ito、IK和IK1)。结果:AP-Q3-100nmol/L浓度依赖性地阻滞Ito,EC50分别为10.5nmol/L,去极化至+50mV时,AP-Q10nmol/L使Ito从给药前的(13.3+-3.4)pA/pF升至(19.46+-4.3)pA/pF。AP-Q0.1-100nmol/L浓度依赖性地增大IK和尾电流(IK tail),EC50分别为4.7nmol/L和5.0nmol/L。AP-Q1pmol/L-100nmol/L浓度依赖性地增大IK1,EC50值为0.2nmol/L。结论:AP-Q增大IK,Ito和IK1的作用可能是其缩短心室肌动作电位时程(APD),增大静息电位(RP)的原因。

Objective ： To study the effects of anthopleurin-Q （AP-Q） on potassium currents of ventricular myocytes in rats and guinea pig. Methods： The ventricular cells of guinea pigs and S.D. rats were obtained by enzymatic method. Whole cell patch clamp technique was used to record potassium currents, including transient outward potassium currents（Ito）, delayed rectifier potassium current （IK） and inward rectifier potassium current （IKI）. Results： AP-Q 3 -100 nmol/L blocked Ito in a concentration-dependent manner with an EC50 value of 10.5 nmol/L. With ＋50 mV depolarized pulse and 10nmol/LAP-Q,the I50 increased from （13.3±3.4）pA/pFto（19.46±4.3）pA/pF. AP-Q 0.1-100 nmol/Lincreased IK and tail current（ IK tail ） in a concentration-dependent manner with EC50 value of 4.7 nmol/L and 5.0 nmol/L, respectively. AP-Q 1 pmol/L-100 nmol/Lincrease IKI in a concentration- dependent manner with EC50 value of 0.2 nmol/L. Conclusion： Augmented effect of AP-Q on/to, IK and IKI may partly explain its effects of shortening APD and increasing absolute value of RP.