无钾、低钠溶液诱发的豚鼠乳头肌触发活动及维拉帕米和蝙蝠葛苏林碱的抑制效应

Triggered Activity Induced by K\++ Free, Na\++ Deficient Solu tion in Guinea Pig Papillary Muscle: the Effects of Verapamil and Daurisoline

延迟后除极引起的触发活动是心律失常发生的细胞机制之一。触发活动是由于心肌细胞 [Ca2 +] i升高并使之发生振荡所致。本实验应用标准微电极技术 ,观察了豚鼠乳头肌标本用含四乙基胺的无钾、低钠溶液灌流后 ,诱导触发活动的情况。结果表明 ,上述溶液可诱导出较稳定且可逆的触发活动。维拉帕米 ( 11μm ol/L )和蝙蝠葛苏林碱 ( 50 μm ol/L)对触发活动均有一定的抑制作用 ,但不能完全消除电位振荡。这种触发活动模型有助于研究抗心律失常药对心肌电活动的作用机制。

Triggered activity induced by delayed afterdepolarizations has been suggested as a cellular mechanism for some arrhythmias. The development of triggered activity should be favored by conditions that increase myoplasmic Ca\+\{2+\} and induce spontaneous oscillatory fluctuation of [Ca 2+ ] i. Using standard microelectrode technique, we observed the electrical activity in guinea pig papillary muscles after perfusion with a K\++ free Na\++ deficient solution containing tetraethylammonium(TEA). The results showed that the solution containing TEA could develop a highly reliable and readily reversible triggered activity. Both of verapamil (11 μmol/L) and daurisoline (50 μmol/L) could inhibit the triggered activity, but not underlying voltage oscillations. The triggered activity induced by TEA solution well suited for studying the effects of antiarrhythmic drugs on this type of electrical activity.