A MODEL OF THE VENTRICULAR CARDIAC ACTION-POTENTIAL - DEPOLARIZATION, REPOLARIZATION, AND THEIR INTERACTION
A MODEL OF THE VENTRICULAR CARDIAC ACTION-POTENTIAL - DEPOLARIZATION, REPOLARIZATION, AND THEIR INTERACTION
复制标题
DOI：
10.1161/01.res.68.6.1501
复制
发表时间：
1991-06-01
影响因子：
20.1
通讯作者：
RUDY, Y
中科院分区：
文献类型：
--
作者：
LUO, CH;RUDY, Y
本文介绍了哺乳动物心肌细胞膜动作电位的数学模型。该模型尽可能基于最近的单细胞和单通道数据，并结合了改变细胞外钾浓度[K]0的可能性。快钠电流I(Na)具有上升速度快(V(Max)=400V/s)和失活恢复慢的特点。与时间无关的钾电流I(K1)包括一个负斜率相，并且随着[K]0的变化表现出显著的交叉现象。与时间相关的钾电流I(K)仅表现出最小程度的交叉。模型中包含了一种在平台电位下激活的新型钾电流。模拟的动作电位复制了实验观察到的[K]0变化对动作电位时程和静息电位的影响。生理模拟的重点是去极化和复极化(即过早刺激)之间的相互作用。结果表明，I(Na)的缓慢恢复在决定细胞反应中的重要性。对周期性刺激的模拟反应包括正常[K]o下的单调Wenckebach模式和交替，而在低[K]o时观察到非单调Wenckebach周期、非周期性模式以及导致不稳定反应(“混沌活动”)的超常兴奋性增强。结果与最近的实验观测结果一致，模型模拟将这些现象与潜在的离子通道动力学联系起来。
A mathematical model of the membrane action potential of the mammalian ventricular cell is introduced. The model is based, whenever possible, on recent single-cell and single-channel data and incorporates the possibility of changing extracellular potassium concentration [K]0. The fast sodium current, I(Na), is characterized by fast upstroke velocity (V(max) = 400 V/sec) and slow recovery from inactivation. The time-independent potassium current, I(K1), includes a negative-slope phase and displays significant crossover phenomenon as [K]0 is varied. The time-dependent potassium current, I(K), shows only a minimal degree of crossover. A novel potassium current that activates at plateau potentials is included in the model. The simulated action potential duplicates the experimentally observed effects of changes in [K]0 on action potential duration and rest potential. Physiological simulations focus on the interaction between depolarization and repolarization (i.e., premature stimulation). Results demonstrate the importance of the slow recovery of I(Na) in determining the response of the cell. Simulated responses to periodic stimulation include monotonic Wenckebach patterns and alternans at normal [K]o, whereas at low [K]o nonmonotonic Wenckebach periodicities, aperiodic patterns, and enhanced supernormal excitability that results in unstable responses ("chaotic activity") are observed. The results are consistent with recent experimental observations, and the model simulations relate these phenomena to the underlying ionic channel kinetics.