卡维地洛对兔心房肌细胞动作电位及离子通道的影响

Effects of carvedilol on action potential and ion channels of rabbit atrial cell

目的实验研究卡维地洛影响兔心房肌细胞电生理的效果。方法兔心房肌单个细胞的制备采用酶解法,动作电位和离子通道电流的记录应用全细胞膜片钳技术。结果 1长期应用卡维地洛显著延长复极90%的动作电位时程(APD90),APD90从82±10 ms延长至116±14 ms;2卡维地洛对心房肌细胞L-型钙电流(ICa-L)没有影响;3卡维地洛可显著减小心房肌细胞的瞬时外向钾电流(Ito),Ito从13.87±1.26 pA/pF减小到8.62±0.91 pA/pF。结论卡维地洛可减小Ito并明显延长APD90,为β阻断剂的抗心律失常效应提供了证据。

Objective To research effects on electrophysiological changes of carvedilol in rabbit atrial cell. Methods Twelve rabbits were randomly divided into control group and carvedilol group. The rabbits in the carvedilol group received oral carvedilol for eight weeks. The rab-bits in the control group received a matching saline. Myocytes were isolated enzymatically from the left atrial appendage. The action potential dura-tion（ APD）,L-type calcium current（ ICa-L）,and transient outward potassium current（ Ito）were recorded using the whole cell patch clamp. Results ①In atrial cells from the carvedilol group,the APD90 was significantly longer at 116 ± 14 ms than in cells from the control group at 82 ±10（n=9 cells,P 〈0.05）. ②There was no significant difference in ICa-L between the two groups. ③Ito in the carvedilol group was signifi-cantly lower than that in the control group（8. 62 ± 0. 91vs. 13. 87 ± 1. 26 pA/pF）. Conclusion Chronic treatment with carvedilol can decrease Ito and prolong APD. It provides mechanistic evidence of anti-arrhythmic actions ofβ-blockade.