通心络对血管平滑肌细胞大电导钙激活钾通道的影响

Effects of Tongxinluo on the large conductance calcium-activated potassium channels in vascular smooth muscle cells

目的:观察通心络对血管平滑肌细胞大电导钙激活钾通道(BKCa)的影响,并从分子水平探讨其扩张血管的可能机制。方法:将SD大鼠随机分为对照组、模型组、低剂量通心络组(0.5g.kg-1.d-1)和高剂量通心络组(1.0g.kg-1.d-1),每组12只,采用腹主动脉结扎技术建立高血压大鼠模型。采用酶消化法分离血管平滑肌细胞,应用标准全细胞膜片钳技术记录各组大鼠血管平滑肌细胞膜BKCa电流幅度值(Am)、平均开放时间(To)、平均关闭时间(Tc)及平均开放概率(Po)的变化。结果:与对照组相比,模型组BKCa通道活性增加,Po增高,Tc缩短(均P<0.01);与模型组相比,通心络两组BKCa通道Po增高,Tc缩短,并呈剂量依赖性(均P<0.01)。结论:通心络能激活大鼠血管平滑肌细胞BKCa通道,发挥扩张血管的功效。

Objective：To explore the vasodilatation mechanism of Tongxinluo by investigating the current density of large-conductance calcium-activated potassium channel （BKCa） in vascular smooth muscle cells （VSMC）. Method..SD rats were randomly divided into control group, model group, low-dose-Tongxinluo group and high-dose-Tongxinluo group （12 in each group ）. Hypertensive model was made by ahdomial aorta constriction. VSMC was obtained after digesting by enzyme. The signals of current amplitude （Am）, open dwell-time （To）, close dwell-time （Tc） and open probability （Po） were recorded by patch clamp technique. Result.. Compared with control group, Po was higher and Tc was shortened in model group （both P〈0.01）. Compared with model group, Po was higher and Tc was shortened in two Tongxinluo groups （all P〈0.01）. Conclusion：Tongxinluo shows vasodilator effects by activating BKCa channels of VSMC in rats.