丹酚酸B对大鼠心室肌细胞瞬时外向钾电流和L型钙电流的阻滞作用

Effect of salvianolic acid B on transient outward potassium current and L-type calcium current in isolated rat ventricular myocytes

目的研究从丹参中分离提取的药物单体——丹酚酸B对大鼠心肌细胞上的瞬时外向钾电流(Ito)、内向整流钾电流(IK1)和L型钙电流(ICa,L)的电生理学作用。方法用酶解法分离大鼠心室肌细胞,全细胞膜片钳技术记录Ito、IK1和ICa,L。每个细胞采用加药前后自身对照,用含100μmol/L丹酚酸B的细胞外液灌流心室肌细胞,记录加药前、后的电流,所有数据均在细胞破膜后20min内完成。结果 100μmol/L的丹酚酸B对Ito和ICa,L具有抑制作用,使Ito和ICa,L最大激活峰值电流密度下降,电流密度-电压曲线下移;且丹酚酸B主要抑制Ito的快速电流成分Itof,而对Ito的缓慢电流成分Itos无明显作用。在60mV测试电压下,Itof的最大激活峰值电流密度从23.51±3.29pA/pF降为16.85±2.36pA/pF,抑制率为28.31%±10.6%(n=8,P<0.05)。在-10mV测试电压下,100μmol/L丹酚酸B作用后ICa,L的最大激活峰值电流密度从-8.66±-2.40pA/pF降为-5.91±-2.14pA/pF,抑制率为31.84%±10.23%(n=11,P<0.05)。丹酚酸B使Ito通道失活后的恢复减慢,但不改变ICa,L的通道动力学。丹酚酸B对IK1无显著作用。结论丹酚酸B对Ito和ICa,L具有阻滞作用,而对IK1无显著作用。

Objective To investigate the effects of salvianolic acid B, an aqueous component of Danshen （salvia miltiorrhiza）, on transient outward potassium current （ Ito ）, inward rectifier potassium currents （ IKI ） and L-type calcium current （ICa,L） in rat ventricular myocytes. Methods Ventricular myocytes were enzymatically isolated from male Sprague-Dawley rats. Whole cell patch-clamp technique was used to record the Ito, IKI and ICa.L in the ventricular myocytes. 100 μmol/L salvianolic acid B was added into the suspension of the myocytes. The data were collected in 20 minutes after the cell membrane rupturing. Results Salvianolic acid B with a concentration of 100 μmol/L decreased the Ito, and ICa,L in rats ventricular myocytes. Further analysis showed that it mainly decreased the fast component of Ito （ Itof ）, but had little effect on the slow component of Ito （Itos ）. At the concentration of 100 μmol/L, salvianolic acid B blocked the peak current and shifted down the current-voltage relation curve of Ito and ICa,L, but had no effect on IKI channel. At membrane voltage of 60 mV, the drug decreased the peak Itof from 23.51 ± 3.29 pA/pF to 16.85 ± 2.36 pA/pF, with the rate of 28.31% ± 10.6% （ n = 8, P 〈 0.05）. And, at membrance voltage of - 10 mV, salvianolic acid B decreased the peak ICa,L from -8.66 ± -2.40 pA/pF to -5.91 ± -2.14 pA/pF, with the rate of 31.84% ± 10.23% （n = 11 ,P 〈0.05）. Salvianolic acid B delayed the recovery from inactivation of Ito, but did not effected the kenetics of ICa,L channel. Conclusion Salvianolic acid B blocks Ito and ICa.L, but have no effect on IKI in ventricular myocytes of rats. [ Chinese Journal of Cardiac Pacing and Electrophysiology ,2010 ,24 （4） ：344 - 348 ]