丹参注射液对模拟缺血预适应引起兔心室肌细胞动作电位和ATP敏感性钾电流变化的影响

目的:探讨丹参注射液对模拟缺血预适应引起兔心室肌细胞动作电位和ATP敏感性钾电流(IK(ATP))变化的影响,试图揭示其保护心肌缺血-再灌注损伤,抗缺血性心律失常作用的离子机制。方法:采用酶解法分离兔左心室细胞,按先后顺序,用正常Tyrode液和模拟缺血液以及模拟缺血液加丹参(750 mg.L-1)灌流,利用膜片钳全细胞记录技术记录不同条件下动作电位和IK(ATP)前后变化。结果:①模拟缺血液灌流后动作电位时程(APD)复极化的50%(APD50)和90%(APD90)分别缩短(与正常组相比P<0.05,n=12);模拟缺血液加丹参灌流,APD50和APD90缩短更加明显,分别缩短了80.46%和71.87%(与正常组相比P<0.01,与模拟缺血液组相比P<0.05,n=12)。静息电位和动作电位幅值无明显改变;②经模拟缺血液灌流,引起IK(ATP)通道的开放,膜电流显示外向性直线形,发生率为58.33%(7/12,P<0.05)。模拟缺血液加丹参,更容易引起IK(ATP)开放,膜电流曲线完全成为直线,诱发率为91.67%(11/12,与正常组和模拟缺血液组相比P<0.05);③Glibenclimide能使这种外向性直线形膜电流恢复为“N”形,证明这种膜电流为IK(ATP);经丹参作用后,改用正常Tyrode液冲洗,心肌细胞上结合的丹参可以被洗脱以及从模拟缺血液中得到恢复。结论:丹参能产生类似心肌缺预适应的病理生理过程,起到了ATP敏感性钾通道开放剂效应,这可能是丹参对心肌缺血预适应的保护作用具有增强效应电生理基础。

Effects of Salvia Miltiorrhiza on Action Potential and ATP-Sensitive Potassium Currents Interfered by Ischemic Preconditioning in Ventricular Myocytes of Rabbit

Objective: To investigate the mechanism of salvia miltiorrhiza on protection myocardial ischemic reperfusion injure and antiarrthymias and study the effects of salvia miltiorrhiza on action potentials(AP) and ATP-sensitive potassium currents(I_(K(ATP))) interfered by ischemic preconditioning(IP) in ventricular myocytes of rabbit.Methods: Single myocytes were dissociated by enzymatic dissociation method.Groups were divided into ① normal Tyrode' solution perfusion;② IP solution perfusion;③ added salvia miltiorrhiza injection(750 mg·L~(-1)) to perfuse in IP solution.The changes of AP and I_(K(ATP))were recorded by whole-cell patch clamp technique under all conditions respectively.Results: ① APD_(50) and APD_(90) on IP perfusion were shortened significantly(P<0.05,n=12),after perfusion with salvia miltiorrhiza group,APD_(50)and APD_(90) were shortened further(to 80.46%,71.87%,with control respectively,P<0.01,with IP,P<0.05,n=12,respectively);but resting potentials and amplitude of action potentials were no changes.② After perfusion with IP,the figures of membrane current changed from "N" type to line type;the door of I_(KATP) was easily opened,and the induced rates were 58.33%(7/12,P<0.05).After perfusion with salvia miltiorrhiza,membrane current shifted outside outstandingly,and I-V curve of I_(K(ATP))almost became a type of line,showing that salvia miltiorrhiza injection induced a very big outward current(91.67%,11/12,with control and IP respectively,P<0.01).③ Above the type of line could be blocked by Glibenclimide and changed into the type of "N";salvia miltiorrhiza would be washed out from ventricular myoctes through perfused by Tyrode solution.Conclusion: Salvia miltiorrhiza injection can be burdened effect of ATP-sensitive potassium channel opener.These may be electrophysiologic basis that salvia miltiorrhiza injection can increase effect about cardioprotection of IP in ventricular myocytes.