【摘要】 本文报告了抗心律失常新药常咯啉对心肌电活动的作用。适当浓度的常咯啉使心肌细胞的动作电位0相的振幅和最大去极化速率减小,2相的复极化速率增大,持续期间缩短,而有效不应期在绝大多数情况下反有延长。心肌活动频率较高时,药物效应更为显著,发展更为迅速。常咯啉能减少无明显外因作用时出现的和由哇巴因引起的心肌自发活动,能对抗乌头碱引起的自发活动。从以上结果来看,常咯啉的作用大概是使控制钠沟道启闭的 m 和 h 两参数的变化时程减慢,使控制动作电位2相的离子外流沟道的 X₁参数加大。文中还讨论了常咯啉对抗心肌自发活动的机理,常咯啉作为抗心律失常药物的分类何题,以及常咯啉对心肌电活动的效应与抗心律失常作用之间的关系问题。更多还原

【Abstract】 The effects of a synthetic new potent antiarrhythmic drug Changrolin（4-{3＇,5＇-bis[（N-pyrroolidinyl）methylene]-4＇-hydroxyphenyl}aminoquinozoline）onthe electrical activity of the endocardial cells of the isolated ventricular septumof guinea pig stimulated repeatedly had been observed by means of capillary glassmicroelectrodes.After treating with Changrolin with concentration around 24μg/ml,the membrane potential of the cell remained practically unchanged,yet theamplitude and the maximum depolarization rate of phase O of the action potentialdecreased,the rate of repolarization of phase 2 increased while its durationshortened.In most cases the effective refractory period prolonged markedly.Theabove mentioned effects of Changrolin developed more promptly and prominentlyas the frequency of stimulation increased from 60 per minute to 200 per minute.Changrolin could decrease the frequency of spontaneous activity of the preparationas well as the rhythmic activity induced by ouabain.It could even abolish com-pletely the rhythmic activity induced by aconitine.It was argued that Changrolincould alter the opening and closing processes of the sodium channel of the membraneduring its activity by influencing the time course of development and restorationof the gating parameters m and h of the respective processes as well as increaseingthe parameter x₁ suggested by McAllister et al.which controls the ionic channelfor the outward current during phase 2 of the action potential.The possiblemechanism of antiarrhythmic action and the possible classification of Changrolinhas been discussed on the basis of the observed effects of Changrolin on theelectrical activity of myocardial cells.更多还原