Mantelli L, Manzini S, Mugelli A, Ledda F
Arch Int Pharmacodyn Ther. 1981 Nov;254(1):99-108.
The ability of some drugs to affect calcium movements in cardiac fibers was tested using a simple method. Guinea-pig ventricular strips were depolarized by 22 mM K+ and their mechanical activity was restored by histamine (10(-5) M); in in these conditions, the effects on contractility of the classic calcium antagonistic drugs nifedipine, verapamil and D600, of the antiarrhythmic drugs lidocaine, quinidine and propafenon, and of a barbiturate, thiopental, were assessed. These drugs were chosen because all of them have been reported as affecting cardiac contractility. It was observed that the ED50 values obtained for the calcium antagonists were in good agreement with those calculated by other authors using different techniques. Moreover, it was found that at high concentrations either the antiarrhythmic drugs or thiopental showed a cardiodepressant activity; the likely explanation of their effects is discussed.
使用一种简单方法测试了某些药物影响心脏纤维中钙运动的能力。豚鼠心室肌条用22 mM K⁺使其去极化，并用组胺（10⁻⁵ M）恢复其机械活性；在这些条件下，评估了经典钙拮抗药硝苯地平、维拉帕米和D600、抗心律失常药利多卡因、奎尼丁和普罗帕酮以及一种巴比妥类药物硫喷妥钠对收缩性的影响。选择这些药物是因为据报道它们都会影响心脏收缩性。观察到钙拮抗剂获得的半数有效量（ED50）值与其他作者使用不同技术计算的值非常一致。此外，发现高浓度时抗心律失常药物或硫喷妥钠均表现出心脏抑制活性；讨论了其作用的可能解释。
