通过阻塞快速延迟整流器电流来证明心房鼻相互作用
E Etienne Verheijck1, Ronald Wilders, Lennart N Bouman
1Academic Medical Center, Department of Physiology, Task Force Heart Failure and Aging, University of Amsterdam, The Netherlands. e.verheijck@amc.uva.nl
Circulation
|February 21, 2002
概括
大心室通常会保护心腔节点 (SA) 免受过度活动的影响. 阻断一个关键的心脏电流 (I(K,r)) 揭示了心房.
科学领域:
- 心血管生理学心血管生理学
- 心脏电生理学心脏电生理学
- 离子通道功能 离子通道功能
背景情况:
- 鼻腔 (SA) 节点启动心跳,但需要保护它免受心房的抑制作用.
- 中部SA节点区域可能会经历最小的心房过极化.
- 了解心房-鼻腔相互作用对于正常的心脏节拍至关重要.
研究的目的:
- 为了研究心房在调节SA节点节拍中的作用.
- 要确定阻断快速延迟整流器电流 (I(K,r)) 对心房 sinus 相互作用的影响.
- 阐明SA节点保护SA节点免受心房影响的机制.
主要方法:
- 利用HERG通道阻断剂E-4031来评估心房-鼻腔相互作用.
- 在体外检查了I(K,r) 阻塞对SA节点和心房电生理学的影响.
- 采用计算机模拟来建模心房-鼻腔电相互作用.
主要成果:
- 在SA节点中阻断I(K,r) 改变了动作电位的配置,但当连接到心房时不会导致停止.
- 耳前膜潜力不受I(K,r) 阻塞的影响,保持SA节点上的超极化负载.
- 将SA节点与心房分离,导致心脏起器在I(K,r) 阻塞时停止,证实了功能性心房-鼻腔相互作用.
结论:
- 大心脏对中央SA节点施加显著的超极化负荷,调节节拍.
- 这种相互作用是控制正常心律的关键机制.
- 这些发现可能解释了长QT2综合征患者中缺少鼻停止的原因,这些患者具有HERG突变.
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