【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(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,EC₅₀、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。更多还原

【Abstract】 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 nmol/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 300 nmol/L shifted the I-V curve to the leftward, changed the membrane potential of half maximal activation to more 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 (rf) of INa was markedly increased by AP-Q 300 nmol/L. CONCLUSION: AP-Q has a stimulating effect on INa with slowing the inactivation course of INa.更多还原