林 敏, 朱才兴, 刘 岩, 高进辽, 徐 斌, 傅义程, 蓝云峰, 李 泱, 张建成. 卡维地洛对陈旧性心梗兔代偿区心肌细胞T-钙电流的作用J. 药学学报, 2012,47(2): 180-187.
引用本文: 林 敏, 朱才兴, 刘 岩, 高进辽, 徐 斌, 傅义程, 蓝云峰, 李 泱, 张建成. 卡维地洛对陈旧性心梗兔代偿区心肌细胞T-钙电流的作用J. 药学学报, 2012,47(2): 180-187.
LIN M,ZHU CX,LIU Y,GAO Jinliao,XU B,FU Yicheng,LAN Yunfeng,LI Y,ZHANG Jiancheng. Effect of carvedilol on T-type calcium current in myocytes of non-infarcted area of the rabbit healed myocardial infarctionJ. 药学学报, 2012,47(2): 180-187.
Citation: LIN M,ZHU CX,LIU Y,GAO Jinliao,XU B,FU Yicheng,LAN Yunfeng,LI Y,ZHANG Jiancheng. Effect of carvedilol on T-type calcium current in myocytes of non-infarcted area of the rabbit healed myocardial infarctionJ. 药学学报, 2012,47(2): 180-187.

卡维地洛对陈旧性心梗兔代偿区心肌细胞T-钙电流的作用

Effect of carvedilol on T-type calcium current in myocytes of non-infarcted area of the rabbit healed myocardial infarction

  • 摘要:

    研究卡维地洛 (Car) 对陈旧性心肌梗死兔代偿区心肌细胞T-钙电流 (ICa,T) 的影响及其机制。选择健康兔行冠状动脉前降支结扎术制备陈旧性心梗模型, 分离代偿区心肌细胞, 利用全细胞膜片钳技术记录ICa,T。结果显示, HMI心肌细胞ICa,T电流明显增加, 30 mV, ICa,T的电流密度从 (0.35 ± 0.02) pA/pF增至 (2.36 ± 0.12) pA/pF。同时, HMI可以使ICa,T的稳态激活曲线向超极化方向移动, 延长电流灭活时间常数和缩短失活后恢复时间, 从而增大了电流幅值。1.0 μmol·L−1 卡维地洛一方面直接抑制ICa,T通道的激活过程减少电流密度, 可降至 (1.38 ± 0.07) pA/pF; 另一方面可以恢复代偿细胞被改变的通道门控参数。结果表明, 卡维地洛可直接降低陈旧性心肌梗死兔代偿区心肌细胞ICa,T电流的密度, 改变其门控特性, 这可能有利于减少心梗后心律失常的发生。

     

    Abstract:

    This article reports the investigation of the effect of carvedilol (Car) on T-type calcium current (ICa,T) of noninfarcted ventricular myocytes in rabbit models of healed myocardial infarction (HMI).  Rabbits with left anterior descending artery ligation were prepared and allowed to recover for 8 weeks, as HMI group.  animals undergoing an identical surgical procedure without coronary ligation were served as the sham-operated group (sham group).  Whole cell voltage-clamp techniques were used to measure and compare currents in cells from the different groups.  Noting that ICa,T density in HMI cells increased markedly to −2.36 ± 0.12 pA/pF (at −30 mv) compared with cells of sham, where little ICa,T (−0.35 ± 0.02 pA/pF) was observed.  Meanwhile, further analysis revealed a significant hyperpolarizing shift of steady-state activation curve of ICa,T in HMI cells, where the time constants of deactivation were prolonged and the time of recovery from inactivation was shortened.  Finally, the amplitude of ICa,T was increased.  Carvedilol (1 µmol·L−1) was found to decrease the amplitude of ICa,T to −1.38 ± 0.07 pA/pF through inhibiting process of ICa,T activation.  Furthermore, carvedilol delayed recovery from inactivation of ICa,T and shortened the time constants of deactivation in HMI cells.  This study suggested that the application of carvedilol in HMI cells contributes to the dynamic changes in ICa,T and may account for reduction of incidence of arrhythmia after myocardial infarction.

     

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