中文摘要：

目的利用人胚肾293细胞表达心脏钠通道SCN5A基因并研究其钠电流特性和对钠通道阻滞剂的反应性。方法野生型SCN5A基因和SCN1B基因共表达于人胚肾293细胞,应用全细胞膜片钳技术记录给药（氟卡尼与利多卡因）前后的钠电流。结果 SCN5A基因转染效率约为60%;测试电压为-40mV时记录到钠电流峰值大小约为-8nA;100μmol/L的氟卡尼轻度抑制钠电流,使钠电流峰值减少（21.1±4.6）%[（-435.8±30.5）pA/pF vs.（-343.9±27.1）pA/pF,P〈0.01];氟卡尼使钠通道激活曲线和失活曲线均呈负向移动,改变的幅值分别是-6.08mV[（-51.88±1.20）mVvs.（-57.96±0.79）mV,P〈0.05]和-9.08mV[（-94.12±0.13）mVvs.（-103.20±0.11）mV,P〈0.05];1Hz和10Hz频率刺激时,氟卡尼使钠电流分别减少（64.5±10.7）%和（83.5±12.2）%（P〈0.01）;30μmol/L利多卡因使钠通道失活后快恢复时间常数和慢恢复时间常数分别延长2倍和3倍。结论表达心脏钠通道SCN5A基因的人胚肾293细胞模型可用于基因特异性的钠通道阻滞剂安全性与药效学筛查。

英文摘要：

Objective To investigate the features of the cardiac sodium channel （SCN5A） expressed in the human embry- onic kidney cells,and to test its response to the sodium channel blockers. Methods Wild-type SCN5A gene was co-expressed with SCN1B gene in human embryonic kidney cells and the membrane currents were measured using a whole-cell patch clamp technique in the absence or presence of flecainide and lidocaine. Results The transfection efficiency of SCN5A gene was about 60%. The peak sodium current amplitude recorded at a test pulse of -40 mV was -8 nA;the peak sodium current amplitude was decreased by （21.1±4. 6）% [（-435.8±30. 5） pA/pF vs. （-343.9±27. 1） pA/pF,P〈0.01] in the presence of 100 μmol/L flecainide. The treatment with flecainide resulted in a negative shift of both curves of the voltage dependence of activation [-6.08 mV,（-51.88±1.20） mV vs. （-57.96±0. 79） mV,P〈0.05] and of inactivation [-9.08 mV, （-94. 12±0. 13） mV vs. （-103.20±0. 11） mV,P〈0. 05]. At stimulus frequencies of 1 Hz and 10 Hz, flecainide produced （64.5± 10.7） % and （83.5±12.2） % （P〈0. 01） reduction in sodium current, respectively. The presence of 30 μmol/L lidocaine led to a 2-fold prolongation of the constant of fast recovery time and a 3-fold prolongation of the constant of slow recovery time from the inactivation status of the sodium channel. Conclusion The human embryonic kidney cells which express the cardiac sodium channel can be used to screen the safety and pharmacodynamics of gene-specific sodium channel blockers.