灯盏花素对大鼠心室肌细胞钠通道的影响

目的：研究灯盏花素对大鼠心室肌细胞膜钠通道的影响，在离子通道水平探讨灯盏花素的抗心律失常作用机制。方法：用急性酶解法获得单个大鼠心室肌细胞，标准的全细胞膜片钳技术记录钠通道电流(INa)。结果：(1)灯盏花素呈浓度依赖性抑制INa，在-30mV时，含1、3、30、100mg·L-1灯盏花素的细胞外液分别灌流细胞3min，分别阻断INa峰电流(7.98±0.60)%、(37.73±2.31)%、(65.58±2.90)%和(88.09±5.60)%。INa激活电位为-70mV，最大峰电位为-30mV，翻转电位为5mV，激活和失活过程呈电压和时间依赖性。30mg·L-1灯盏花素使电流电压曲线明显上移,峰值电流从（13.49±1.25）pA/pF减少至（4.78±0.85）pA/pF,n=8，P<0.05，冲洗后可以不完全恢复。（2）灯盏花素能使钠电流失活曲线明显左移。（3）灯盏花素使钠电流激活曲线明显右移。（4）灯盏花素使钠电流复活明显减慢。结论：灯盏花素能够抑制心肌细胞钠通道电流，并呈浓度依赖性。

Effect of breviscapin on INa channel current in isolated rat ventricular myocytes

AIM: To investigate the effects of breviscapine on INa channel in isolated rat ventricular myocytes. METHODS: Single cell of rat ventricular myocyte was isolated by enzymatic dissociation. The whole-cell patch-clamp recording technique was used to observe the change of INa channel current influenced by breviscapine. RESULTS: Breviscapine decreased the INa channel current in a dose-dependent and voltage-dependent manner in rat ventricular myocytes. The current-voltage curve was significantly decreased. Breviscapin at concentrations of 1, 3, 30, 100 mg/L respectively decreased INa current density, which were (7.98±0.60)%, (37.73±2.31)%, (65.58%±2.90)% and (88.09±5.60)%, respectively. INa was inhibited in a voltage-dependent manner, showing a significant attenuating effect at test potentials from -30 mV to 0. The INa inactivation curve was shifted to left and the activation curve was shifted to right. Breviscapine step down the recovery curve significantly. CONCLUSION: Breviscapine concentration-dependently decreased INa channel current in rat ventricular myocytes.