心肌梗死后β2受体对心肌细胞L型钙通道电流的调控作用  

The regulation effects of β2 adrenergic receptor on ICaL in myocytes from infarcted heart

作　　者：杨蕙[1] 伍卫[2] 邓春玉[3] 

机构地区：[1]广州市第一人民医院,510180 [2]中山大学附属第二医院 [3]广东省心血管病研究所

出　　处：《中华心律失常学杂志》2009年第2期150-154,共5页Chinese Journal of Cardiac Arrhythmias

基　　金：广州市科技攻关引导项目（200423-E0331）

摘　　要：目的研究β2肾上腺素受体（β2受体）对心肌梗死后心肌细胞L型钙通道电流（‰）的调控作用。方法Wistar大鼠随机分为正常对照和心肌梗死组，制作心肌梗死模型。分离心肌细胞，应用全细胞膜片钳技术，观察心肌梗死后ICaL变化，先后给予β2受体激动剂salbutamol（10μmol／L）及β2受体阻滞剂ICI118，551（0．1μmol／L）后再观察ICaL的变化。结果心肌梗死后8周ICaL显著减低37．0％（P〈0.05）。在正常和梗死后8周后心肌细胞，β2受体激动剂均显著增加ICaL（P〈0．05），心肌梗死后对ICaL的调节作用较正常心肌细胞增强（23．4％±1．7％对33．1％±3．3％，P〈0.05），这种作用可被抑制型G调节蛋白（Gi蛋白）抑制剂放大，被环磷酸腺苷依赖蛋白激酶（PKA）拈抗剂抑制。结论β2受体对ICaL具有调节作用，且心肌梗死后这种调节作用增强，提示心肌梗死后β2受体在恶性心律失常发生中的作用可能提高。Objective To investigate the regulatory effects of β2-adrenergic receptor（β2-AR） on L- type calcium current （ICaL） in myocytes from infarcted heart. Methods Adult Wistar rats were randomly divided into two groups, the control group and the post-myocardial infarction （ MI ） group. The rat chest was opened and the left anterior descending coronary artery was ligated. The control group rats underwent sham-operated without coronary artery ligation. Myocytes were enzymatically disassociated by Langedorff perfusion. The whole cell-patch clamp recording technique was used to record ICaL in specific pipette solution and superfusion according to specific holding potential and command potential program. The responses of cardiomyocytes to IB2- AR agonist salbutamol （ 10 μmol/L）and then to β2-AR antagonist ICI118,551 （0. 1 μmol/L）were examined. Results ICaL in ventricular myocytes from the border zone of infarcted heart decreased by 37.0% significantly after MI（ P 〈0. 05 ）. β2-AR agonist increased ICaL more dramatically in myocytes from post-MI heart than in controls（23.4%±1.7% vs 33.1% ±3.3%, P〈0.05）. Conclusion The regulatory effects of β2-AR on ICaL in myocytes are stronger after MI. It was suggested that β2-AR may responsible for the genesis of malignant arrhythmia after MI.

关 键 词：心肌梗死 Β2肾上腺素受体 L型钙通道电流 

分 类 号：R542.22[医药卫生—心血管疾病]