Loss of function and gain of function mutations of the sodium channel were investigated using an intact two-dimensional rabbit sinoatrial node (SAN) and atrial cell model. The effects of three external stimuli (acetylcholine secretion by the vagal nerve, acid-base concentration, and tissue temperature) on cardiac pacemaker function and conduction were studied. Our results show that these two groups of mutations have different effects on pacemaker function and conduction. Furthermore, we found that the negative effects of these mutations could be altered by external stimuli. The bradycardic effects of mutations were magnified by an increase in acetylcholine level. Changes in acid-base concentration and tissue temperature increased the ability of the SAN to recover its pacemaker function. The results of this study increase our understanding of sodium channel disorders, and help to advance research on the treatment of these conditions.
目的:本文采用VC语言编程,借助MFC(Microsoft Foundation Classes)模块强大的绘图功能,用于仿真模拟心脏等复杂非线性体系的动力学过程。方法:首先,利用MFC程序模块整合的视图开发功能,将复杂体系各控制参量设置为面板上不同按钮,通过点击按钮观察复杂体系动力学过程随控制参数变化的情况;其次,通过添加放大或缩小功能按钮,可以方便地观察复杂相图的局部分形细节;再者,添加恰当的鼠标响应效果,可以实时观察不同条件下的动态演化效果。结果:利用视图仿真重点研究了心脏体系窦房结组织搏动过程,实时观察外界环境刺激对其起搏活动的调控作用,动态跟踪不同参数条件下,膜电压产生及传导的演化过程。通过仿真模拟与实验数据对比,揭示环境扰动与心律失常之间的内在联系及作用机制。结论:将MFC用于视图仿真,具有方便的可扩展性、直观形象的可视化效果、便利的局部放大功能等优点。模拟过程既直观形象,又方便明了,便于将来构建心脏等复杂系统的三维模型,进一步研究心脏的搏动过程。
