Oozeer视神经纤维膜动力学特性的仿真

Simulation of Dynamic Membrane Properties for Oozeer Optic Nerve

目的对Oozeer视神经纤维的膜特性进行仿真,研究不同离子通道在动作电位产生过程中的作用。方法利用Matlab编程和欧拉数值计算法对Oozeer视神经模型的膜动力学特性进行仿真;相平面图法分析脉冲电流对膜电位的相图和有无A型电流存在的dV/dt对V的相图。结果相图分析表明,动作电位的上升阶段主要是因为传统的快速钠离子流,而A型电流在复极化阶段起主要作用,持续钠离子流和慢速钾离子流的影响较小。A型电流存在时产生延迟的动作电位,且缩短动作电位的持续时间,膜电位升高到尖峰阈值时,膜电位的上升减缓。结论不同离子电流在动作电位形成过程中起不同作用,A型电流使视神经纤维膜动作电位复极化,对超极化后电位起主要作用。

Objective To study the roles of different ion channels during the action potential generation process by simulating the Oozeer Optic Nerve model＇ s membrane properties. Methods The Oozeer optic nerve model＇ s dynamic membrane properties were simulated using Matlab and Euler＇ s method. The phase plots of current versus membrane potential and dV/dt versus V with and without A-type current were analyzed during the im- pulse. Results Four ion channels in Oozeer Optic Nerve Model played different roles in forming the action po- tential. It could be seen that, from the phase diagram of dV/dt versus V, the ascent stage of action potential was mainly affected by the traditional fast sodium current and A-type potassium played a major role in the re- polarization, while the influence of continuous sodium current and slow potassium current was very small. The existence of A-type current would produce delayed action potential and reduce the duration of time. As the membrane potential increased towarded the spiking threshold, the rise of the membrane potential became slow. Conclusion Different ion currents have different effect on the formation of action potential. It is A-type current that influences repolarization of optic nerve fiber action potential as well as hyperpolarization.