丹参酮Ⅱ-A抑制豚鼠单个心肌细胞L型钙电流和缩短动作电位时程效应的相关性分析

Relative analysis of inhibiting effect of L type Ca^(2+) current and shortening effect of action potential duration of danshentong Ⅱ-A in guinea pig ventricular myocytes

目的旨在探讨药物阻断L型钙电流与其缩短心肌细胞动作电位时程（APD）效应之间的相互关系。方法采用膜片钳全细胞式记录方法，同时观察了丹参酮Ⅱ-A（DST）对豚鼠同一个心室肌细胞跨膜电位和L型钙电流的影响，并对药物的有关效应作相关分析。结果DST显著缩短豚鼠心肌单细胞的动作电位时程（APD），呈剂量依赖关系（r=-0.987）;10、20、和40μmol·L-1DST可使L型钙内向峰电流分别减少35.2％、57.7％和74.7％，亦呈浓度依赖方式（r=-0.948）。经相关性分析证实，在本实验采用的DST相应浓度作用下，APDS50、APD90和APD50～10的缩短与L型钙电流峰值的减少之间呈高度正相关（r分别为0.9870、0.9867和0.9896）。结论DST缩短心肌细胞APD和阻断L型钙电流的效应是高度一致的，且以APD50～10表示平台期的长短更合理。

AIM To explore relationship between shortening of action potential duration and blocking of L type Ca2+ current of certain agent. METHODS The effect of danshentong Ⅱ-A (DST) on transmembrane potential and L type Ca2+ channel current in guinea pig single ventricular myocytes were observed simultaneously using patch clamp whole-cell recording technique. RESULTS DST markedly shortened the action potential duration (APD ) in dose-dependency (r=-0. 987); DST 10, 20 and 40μmol· L-1 reduced verapamil-sensitive Ca2+ inward current by 35. 2%, 57. 7% and 74. 7%, respectively, also in dose-dependent manner (r=-0. 948 ). Relative analysis demonstrated that there is significant positive relation between shortening of APD50, APD90, APD50～10 and reducing of L type Ca2+ peak current (r was 0. 9870, 0. 9867 and 0. 9896, respectively) in range of corresponding concentration of DST. CONCLUSIONS The shortening effect of APD in myocardial cell of drug is markly consistent with drug's blocking effect of L type Ca2+ current. And it is reasonable that APDS50～10 is as plateau of APD.