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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(I_(Na))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 3-30nmol/L浓度依赖性地增大I_(Na),EC_(50)、为104nmol/L(95％可信范围:78-130nmol/L)。AP-Q 300nmol/L使I-V曲线左移,使半数激活电压从(-36.3±2.3)mV变为(-43±23)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I_(Na)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I_(Na)的快速失活时间常数(τ_f)。结论:AP-Q对I_(Na)有促进作用并减慢其失活过程。
OBJECTIVE: To study the effect of anthopleurin-Q (AP-Q) extracted from Anthopleura xanthogrammica on sodium current (I_(Na)) in ventricular myocytes of guinea pigs. METHODS: Single ventricular myocytes of guinea pigs were isolated by enzymatic digestion and sodium currents in ventricular myocytes were recorded using whole cell patch clamp technique. Results: AP-Q 3-30nmol/L concentration-dependently increased I_(Na), EC_(50), 104nmol/L (95% confidence range: 78-130nmol/L). AP-Q 300 nmol/L shifts the IV curve to the left, so that the half activation voltage is changed from (-36.3±2.3) mV to (-43±23) mV (n=6, P<0.01), and the half inactivation voltage is from (-) 75±6) mV becomes (-59±5) mV (n=6, P<0.01). AP-Q 300nmol/L reduced the I_(Na) half recovery time from (114±36) ms to (17±2) ms (n=6, P<0.01), and significantly slowed the rapid loss of I_(Na). Live time constant (τ_f). CONCLUSION: AP-Q has a promoting effect on I_(Na) and slows its inactivation.