海星甾烯AST对离体豚鼠心房肌的作用

Effect of Succinic di- （3β--hydroxyandrost o-5-en-17-one ester （AST） on Isolated Guinea Pig Atria

目的观察从海星提取并经结构修饰而获得的新化合物丁二酸二-3β-羟基雄5烯-17酮酯（AST）对离体豚鼠心房肌的作用，并初步探讨其抗心律失常作用机制。方法采用豚鼠离体心房肌，测定给药前后右心房肌的心肌收缩力、心率，左心房静息后增强作用、正性阶梯现象及不应期的变化。结果AST能明显降低豚鼠离体右心房肌的收缩力，同时减慢其心率；抑制豚鼠离体左心房肌的正性阶梯和静息后增强作用，延长豚鼠左心房的有效不应期。结论AST的抗心律失常作用可能与其降低心房肌的自律性和兴奋性有关。

Objective To observe the effects ofsuccinic di-（3β-hydroxyandrost-5-en-17-one ester （AST） on isolated guinea pig atria, and to discuss the antiarrhythmic mechanism. Methods On isolated guinea pig atria, the effects of AST were studied on myocardial contractility, heart rate, post-rest potentiation, positive staircase phenomenon and effective refractory period. Result In isolated guinea pig right atria, AST significantly lowered myocardial contractility, induced heart rate, depressed the post-rest potentiation and positive staircase phe- nomenon, and prolonged effective refractory period （ERP） of isolated guinea pig left atria. Conclusion AST can lower myocardium rhythm and excitability possibly to be one of the antiarrhythmia mechanisms.