摘要
大鼠心室肌纤维经低温(4℃)处理19—21小时后,动作电位幅度及复极50％时的动作电位时程无明显变化,而复极90％的时程明显延长。低钾(0.75—1.5mmol/L)灌流可使低温处理的标本产生迟后去极化(DAD)以及由此产生触发性活动(TA)。施与额外电刺激对TA无影响,或引起该节律的重排,然而不能使之终止。肾上腺素(1μg/ml)或高钙(5.4mmol/L)可以增加DAD幅度,从而使TA更易发生。TI^+(1.5mmol/L)及Mn^(2+)(3mmol/L)可抑制DAD及TA。以上结果表明,低温处理后大鼠心室肌细胞电生理特性发生改变,对钠钾泵抑制剂—低钾—敏感性增高,因而易产生DAD及TA。
After cold treatment (4℃) for 19-21 h, the amplitude of action potential and the action potential duration at 50% of repolarization of the rat ventricular fibers were unchanged significantly, whereas that of 90% of repolarization increased remarkably.Low K+(0.75-1.5 mrnol/L) superfusion might induce delayed af terdepolarization (DAD) and triggered activity (TA) in the papillary muscle fibers treated with cold storage. Application of electrical stimulation either did not affect or only resettle the rhythm of the TA, but it could not stop it.Adrenaline (1μg/ml) or high. concentration of Ca2+ (5.4 mmol/L) could iacrease the amplieude of DAD and made the TA more easily be induced. Both T1+ (1.5 mmol /L) and Mn2+ (3mmol/L) could inhibit DAD and TA. The results showed that the electrophisiological properties of the ventricular fibers of rat heart were changed after cold storage. It is suggested that the sensitivity of Na-pump in the cell membrane is increased to the pump-inhibitors and the DAD and TA are induced more easily by low K+ superfusion after cold treatment.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1989年第6期754-758,共5页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金
关键词
心室肌
触发性活动
低钾
大鼠
Action potential
Ventricular fiber
Cold treatment
Low K+
Triggered activity
