丹皮酚对豚鼠心肌细胞动作电位及钙通道电流的影响

目的 :研究丹皮酚对分离的单个豚鼠心肌细胞动作电位及钙通道电流 (ICa)的影响。方法 :单个细胞膜片钳技术。结果 :①丹皮酚 40 0 μg/ml可使动作电位时程 (APD)明显缩短。APD50 和APD90 分别由给药前的 (35 2±2 7)ms和 (416± 33)ms缩短至 (16 8± 2 0 )ms和 (2 6 5± 2 3)ms(P <0 .0 5 ,n =5 ) ,分别缩短了 5 2 .2 %和 35 .6 % ,而静息电位和动作电位幅值无明显改变 ;② 5 0～ 40 0 μg/ml丹皮酚浓度依赖性阻滞ICa,使其最大峰值由 (916 .7± 197.3)pA分别降至 (5 83 .3± 10 8.8)pA和 (2 5 0 .0± 12 0 .0 )pA(P <0 .0 1) ,抑制率分别为 36 .4%和 72 .7% ,并使ICa的I V曲线上移 ,但不使I V曲线发生偏移。结论 :丹皮酚对ICa的阻滞作用为其抗心律失常作用的主要机制之一

Effect of Paeonol on Action Potentials and CalciumChannel Currents in Isolated Single Ventricular Myocyte of Guinea Pig

Abstract:To observe the effects of Paeonol (Pae) on action potentials and calcium channel curren(I Ca ) in isolated ventricular cells from guinea pig hearts. Methods: Patch clamp whole cell recording techniques were used. Results: The results indicated that:①400 μg/ml Pae could shorten APD 50 and APD 90 from(352±27)ms to(168±20)ms,and(416±33)ms to (265±23)ms(52.2%,35.6%,P<0.05,n=5) respectively, but had no significant effect on rest potential and action potential amplitude,and ② Pae at 50 μg/ml to 400 μg/ml inhibited peak current of I Ca from(916.7±197.3)pA to(583.3±108.8)pA, and(250.0±120.0)pA(36.4% to 72.7%,P<0.01,n=5) respectively.It revealed that Pae blocks I Ca with a concentration dependence manner.Pae shifted up the current voltage curve but exerted no effects on peak current potential. Conclusion: These results suggest that Bolcking effects of Pae on I Ca were the major mechanism of its antiarrhythmic action.