海葵毒素anthopleurin-Q对豚鼠心室肌细胞钠电流的作用

摘要

目的:研究从海葵(Anthopleura xanthogrammica)提取的毒素anthopleurin-Q(AP-Q)对豚鼠心室肌钠电流(INa)的作用.方法:用酶消化法分离豚鼠单个心室肌细胞,用全细胞膜片箝技术记录心室肌细胞钠电流.结果:Ap-Q 3-30 nmol/L浓度依赖性地增大INa,ECso为104 nmoL/L(95%可信范围:78-130nmol/L).AP-Q 300 nmol/L使I-V曲线左移,使半数激活电压从(-36.3±2.3)mV变为(-43±3)mV(n=6,P＜0.01),半数失活电压从(-75±6)mV变为(-59±5)mV(n=6,P＜0.01).AP-Q 300nmol/L使INa半数恢复时间从(114±36)ms缩短为(17±2)ms(n=6,P＜0.01),并明显减慢INa的快速失活时间常数(τf).结论:Ap-Q对INa有促进作用并减慢其失活过程.%AIM: To investigate the effects of a sea anemone toxin anthopleurin-Q (AP-Q) isolated from Anthopleura xanthogrammica on sodium current (INa) in isolated guinea pig ventricular myocytes. METHODS: Single myocytes were dissociated by enzymatic dissociation method. INa was recorded using whole-cell patch-clamp technique. RESULTS: AP-Q (3 - 300 mol/L) increased INa in a concentration-dependent manner. The EC50 value for increasing INa Was 104 nmol/L (95 %confidence range: 78 - 130 nmol/L ). AP-Q 300mol/L shifted the I-V curve to the leftward, changed the membrane potential of half maximal activation to rore negative potential from (- 36.3 + 2.3 ) mV to (-43 ±3) mV (n =6, P ＜0.01) and changed the membrane potential of half maximal inactivation to more positive potential from ( - 75 + 6) mV to ( - 59 + 5) mV ( n = 6, P ＜ 0.01 ). AP-Q 300 nmol/L shortened the half-recovery time of INa from (114 + 36) ms to (17 + 2)ms (n = 6, P ＜ 0.01). The fast inactivation time constant (τf) of INa Was markedly increased by AP-Q 300nmol/L. CONCLUSION: AP-Q has a stimulating effect on INa with slowing the inactivation course of INa.