IKr和IK异质性对动作潜力的持续时间及其速率依赖性的影响:一个模拟研究
P C Viswanathan1, R M Shaw, Y Rudy
1Cardiac Bioelectricity Research and Training Center, Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA.
Circulation
|May 11, 1999
概括
心室肌细胞再极化受到缓慢延迟整流器电流 (IKs) 密度变化的影响. 细胞间合显著影响动作潜能持续时间的异质性,影响心律失常风险.
科学领域:
- 心脏电生理学 心脏电生理学
- 计算生物学 计算生物学
- 离子通道生理学 离子通道生理学
背景情况:
- 室腔心肌在离子通道表达和电生理学上表现出异质性.
- 快速 (IKr) 和缓慢 (IKs) 的延迟直流器电流是作用电位再极化和持续时间的关键决定因素.
研究的目的:
- 通过LRd模型研究IKr和IKs异质性对动作潜能持续时间 (APD) 和其速率依赖性的影响.
- 阐明细胞间合在调节心室肌肉内APD异质性的作用.
主要方法:
- 利用哺乳动物心室细胞的LRd计算模型.
- 在不同IKs和IKr密度的条件下模拟的电生理学特性.
- 研究了在多细胞纤维模拟中不同程度的间隙连接合的影响.
主要成果:
- 减少IKs密度 (例如,在M细胞中) 会导致长时间的APD和一个的APD-率关系.
- 积累的IKs激活和增加的-交换电流 (INaCa) 有助于急剧的APD速率适应.
- 细胞间隙连接合显著降低APD异质性;减少合使其最大化.
结论:
- IKs中的异质性:IKr密度是APD及其速率依赖的主要决定因素.
- 完整的心肌中的隙结合在确定APD异质性和再极化分散程度方面发挥着至关重要的作用.
- 这些发现对于理解复极异常和像长QT综合征这样的心律失常具有临床意义.
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