在人类慢性心房中,G蛋白结合内向整正K+) 电流 (IK,ACh) 的下调的分子基础:GIRK4 mRNA的下降与IK,ACh的减少以及肌受体介导的动作潜力的缩短有关
1Department of Pharmacology, University of Technology, Dresden, Germany. dobrev@rcs.urz.tu-dresden.de
Circulation
|November 21, 2001
概括
人类的慢性心房 (AF) 降低了G蛋白合的向内调整的K+电流 (IK,ACh) 的调节,并提高了向内调整的K+电流 (IK1) 的调节. 在AF中的这种电力改造使肌细胞适应高速率.
科学领域:
- 心脏病学 心脏病学
- 电子生理学 电子生理学
- 分子生物学分子生物学
背景情况:
- 副交感神经系统与心房动 (AF) 病变发生有关.
- 在慢性AF中,G蛋白结合的向内调整K ((+) 电流 (I ((K,ACh)) 的作用尚不清楚.
研究的目的:
- 调查慢性AF患者在人类心房肌细胞中的I(K,ACh) 和其GIRK4亚单元的变化.
- 检查AF中变异离子电流的功能相关性.
主要方法:
- 隔离的人类心房肌细胞中的电生理学记录.
- 使用竞争性逆转录聚合酶链反应,对GIRK4和Kir2.1mRNA水平进行定量分析.
- 评估动作潜力的持续时间和对肌肉蛋白受体刺激的反应.
主要成果:
- 在AF肌细胞中,I(K,ACh) 密度降低了约50%,GIRK4 mRNA减少.
- 在AF中,向内调整的K ((+) 电流 (I ((K1)) 密度翻了一番,并增加了Kir2.1 mRNA.
- 动作潜力的持续时间在AF中减少,肌肉蛋白受体介导的缩短减弱.
结论:
- 慢性AF导致人类心房中I(K1) 的转录上调和I(K,ACh) 的下调.
- 这些离子通道的变化减弱了肌肉类受体对作用潜力的影响.
- 耳前肌细胞下调I ((K,ACh) 以适应慢性高速率,抵消电力重塑效应.
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