Rosenthal J E, Ferrier G R
J Pharmacol Exp Ther. 1982 Apr;221(1):188-96.
The purposes of this study were to determine whether amrinone induces oscillatory afterpotentials (OAP) or aftercontractions (AC) in Purkinje tissue or myocardium, to determine whether a relationship exists between the production of OAP or AC and the inotropic effects of amrinone and to determine possible effects of amrinone on the oscillations and the positive inotropic effect produced by digitalis. Isolated canine papillary and trabecullar muscles, as well as false tendons, were exposed to 5.3 X 10(-4) M amrinone. Some of the preparations had been pretreated with acetylstrophanthidin (AS) in a dose just sufficient to induce OAP or AC. Standard electrophysiologic techniques were used to record transmembrane action potentials. Developed tension also was recorded. Amrinone by itself did not induce OAP or AC in myocardium or false tendons. This was true even when the resting membrane potential of the false tendons was reduced by means of focal current application. Amrinone increased the amplitude of AS-induced oscillations in both myocardium and false tendons. Amrinone increased strength of contraction of untreated myocardium at all basic cycle lengths and of AS-treated myocardium, especially at shorter basic cycle lengths. Amrinone decreased strength of contraction both of untreated and AS-treated false tendons at all basic cycle lengths. The results suggest that there may be important differences in the mechanisms of action of amrinone and digitalis.
本研究的目的是确定氨力农是否会在浦肯野组织或心肌中诱发振荡后电位（OAP）或后收缩（AC），确定OAP或AC的产生与氨力农的正性肌力作用之间是否存在关系，并确定氨力农对洋地黄产生的振荡和正性肌力作用可能产生的影响。将离体犬乳头肌、小梁肌以及腱索暴露于5.3×10⁻⁴M的氨力农。部分标本预先用乙酰洋地黄毒苷（AS）进行预处理，剂量刚好足以诱发OAP或AC。采用标准电生理技术记录跨膜动作电位。同时记录收缩张力。氨力农本身不会在心肌或腱索中诱发OAP或AC。即使通过局部施加电流降低腱索的静息膜电位，情况依然如此。氨力农可增加心肌和腱索中AS诱发的振荡幅度。氨力农可增加未处理心肌在所有基础周期长度下的收缩强度，以及AS处理心肌的收缩强度，尤其是在较短的基础周期长度时。氨力农可降低未处理和AS处理的腱索在所有基础周期长度下的收缩强度。结果表明，氨力农和洋地黄的作用机制可能存在重要差异。
