用外界刺激调节窦房结心房体系中的异常搏动行为

Elimination of Abnormal Pacemaking by External Stimulation in an Intact SA Node-Atrium Model

本文引入外部扰动对副交感神经系统分泌乙酰胆碱的影响,利用计算机模拟考察了外部扰动对窦房结组织动作电位积极的调控作用.可以观察到,在老龄化心脏体系中,由于窦房结组织中钠电流的降低或活性细胞数量的减少,会引起心脏起搏活动的变慢甚至出现死振.不过该死振现象可以通过引入外部低频信号来减轻或消除.再者,体系内外环境噪声也有类似的作用效果.上述现象表明,在控制心脏的起搏活动过程中,外部扰动有着重要的调节作用.

In this study,by theoretic simulation we have studied the important role of an external stimulation on the pacemaking action of SA node（SAN）tissue.When introducing an external stimulus to activity of vagal tone activity,a concentration dependent effect of acetylcholine（ACh：a neurotransmitter）released by parasympathetic nerves system is considered.Our results display that in senile heart,decrease of INafrom the SAN or increase of the death number of SAN cells slows down or even induce the cease of cardiac pacemaking. However,such ceased cardiac behavior can be resumed by adding external fluctuations.In addition,the similar effect of noise is also discussed.This phenomenon suggests the positive role of external signal in adjusting the pacemaker activity.