六种强心甙对羊心脏浦肯野纤维钠泵活动的抑制作用  

Inhibitory effects of 6 cardiac glycosides on sodium pump in sheep Purkinje fibers

作　　者：韩大英[1] 

机构地区：[1]首都医学院心血管生理研究室

出　　处：《中国药理学报》1994年第3期244-249,共6页Acta Pharmacologica Sinica

摘　　要：用离子选择微电极定量研究了数种强心甙对羊心脏浦肯野纤维膜钠泵活动的抑制作用,表明从30 nmol·L^(-1)开始a^1Na有较明显的升高,较高浓度(0.4μmol·L^(-1))时a^1Na进一步升高,后除极(DAD)出现时钠泵活动抑制的百分比在不同药物较接近,其范围在52.8％—65.5％。经计算,由于钠泵受抑制细胞摄取Na^+引起的内向电流能引起异常自律活动。The inhibitory effects of 6 cardiac glycosides (digoxin , meproscillarin , acri-hellin , deslanoside, ouabain, K-strophanthin) on sodium pump in sheep Purkinje fibers were studied. Isolated Purkinje fibers were used and stimulated at 0. 4 Hz regularly. Intracel-lular sodium activity (a1Na), potassium activity (a'K ) and membrane potential (Em) were monitored with single barrel normal and ion-selective micro-electrodes. It was shown that a'Na rose definitely from the concentration of 30 nmol·L-1, and became more significant until the dose of 0. 4 μmol·L-1. a'Na rose very much faster within the range of toxic doses (from 1 - 20 μmol·L-1 to 1 mmol·L-1). The occurrence time of delay afterdepolarization (DAD) after adding drugs varied with various drugs used, or with different experiments, hence the time points of DAD and Aa'Na-time, concentration relation curves were quite scattered. But when basing on the appearance of DAD as a common time point we calculated the temporal variation of a'Na before and after toxic effect, the relation curves in a same sort of glycoside were kept uniform. When the toxic effects of glycosides appeared , the inhibition degree of sodium pump activity was quite close ( between 52. 8% and 65.5%), suggesting that there existed close relationship between sodium pump inhibition and toxic effects of glycosides. Intracellular potassium ions lost progressly within the scope of subtoxic doses (10 - 30 nmol·L-1) and lost more significantly within the scope of toxic doses (1 - 20 μmol·L-1). Based on the results of calculation, the inward current induced by the sodium pump inhibition might be responsable for the abnormal automaticity.

关 键 词：浦肯野纤维 微电极 强心甙 膜电位 

分 类 号：R972.1[医药卫生—药品]