摘要
目的 研究甲状腺素诱发大鼠心肌肥厚模型的心肌细胞瞬时外向钾电流、内向整流钾电流和钙电流的变化。方法 以 ip L -甲状腺素造成大鼠心肌肥厚模型后 ,用膜片钳技术记录心肌细胞瞬时外向钾电流、内向整流钾电流和 L型钙电流。结果 肥厚组心肌细胞瞬时外向钾电流幅度和密度均增加 ,激活动力学特性无改变 ;内向整流钾电流幅度和密度也增加 ,激活动力学特性也无改变 ;而钙电流幅度、细胞膜电容增加 ,电流密度不变 ,半数激活电压 ( V1 /2 )向负电位方向移动 ,斜率 ( k)减小。结论 在甲状腺素诱发大鼠心肌肥厚模型中瞬时外向钾电流、内向整流钾电流和钙电流特性均发生了变化 。
Objective To investigate the changes of transient outward potassium current,inward rectifier potassium current and calcium current in normal and hypertrophied rat ventricular myocytes in thyroxine induced hypertrophy. Methods Myocardial hypertrophy was induced by ip L Thyroxine in rats.The whole cell patch clamp technique was used to record these currents. Results The currents (I k1 and I to ) were larger in hypertrophied cells (571 5,1256 6pA) than that in normal cells (374 1,419 2pA).When related I k1 and I to amplitude to the cell membrane area,as estimated by membrane capacitance measurement,there were significant differences in current density (4 37 vs 5 19,4 94 vs 10 17pA/pF) in both normal and hypertrophied cells,respectively.Whereas I to and I kl revealed the same voltage dependence.The potential giving 50% of activation (V 1/2 ) did not change in hypertrophied cells,neither did the slope of activation curve.The calcium current was found to be larger in hypertrophied cells (783pA) than that in normal cells (433pA).However,there was no significant difference in current density (6 54 vs 8 33pA/pF) between them.The potential giving 50% of activation (V 1/2 ) moved towards more negtive and the slope of activation curve was smaller in hypertrophied cells. Conclusion In the model of thyroxine induced hypertrophy,the properties of transient outward potassium current,inward rectifier potassium current and calcium current had changed a lot,which contributed to the electrophysiologic abnormalities in myocardial hypertrophy.
出处
《中华心律失常学杂志》
2001年第1期44-48,共5页
Chinese Journal of Cardiac Arrhythmias
关键词
心肌肥厚
膜片钳
瞬时外向钾电流
甲状腺素
内向整流钾电流
钙电流
Myocardial hypertrophy
Patch clamp
Transient outward potassium current
Inward rectifier potassium current
Calcium current
