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[The modulation of 4-aminopyridine sensitive potassium channel to bifurcationscenario of the spontaneous neural firing rhythms.] [Ariticle in Chinese]

SONG Shao-Li, WEI Chun-Ling, GU Hua-Guang, Liu Zhi-Qiang^*, REN Wei

College of Life Science, Shaanxi Normal University, Xi'an 710062, China

Abstract

Neuronal firing is crucial to the information processing in the nervous system. In order to make a further study of bifurcationscenarios, experiments were performed on neural pacemakers formed at the injured site of rat sciatic nerve subjected to chronic ligatures.We chose the conductance of voltage-dependent potassium ion channels as conditional parameter, and the extracellular calcium concentrationas bifurcation parameter, to give a demonstration of how the firing pattern of neural pacemaker responses to dual parameteradjusting. Among 28 preparations observed, 21 were insensitive to dual parameter adjusting since no change of bifurcation scenariostructure was detected. On the contrary, the residual 7 preparations showed dramatic bifurcation scenario shifting corresponding todifferent dual parameter configuration. Briefly, when concentration of 4-aminopyridine (4-AP), a voltage-dependent potassium ionchannels blocker, was kept at different level and extracellular Ca2+ concentration was decreased gradually, different bifurcation scenariosof firing patterns were exhibited in an identical neural pacemaker. The two-parameter bifurcation scenarios of experimental neuralpacemaker with different parameter configuration were also different. The results show that neural firing pattern is different when theparameter configuration is different, and the bifurcation scenario is a fundamental framework to identify the transitions between firingpatterns.

Key words: neural firing; bifurcation; chaos; 4-aminopyridine

Received: 2009-10-14　　Accepted: 2009-11-19

Corresponding author: 刘志强　　E-mail: zqliu1969@163.com

Citing This Article：

SONG Shao-Li, WEI Chun-Ling, GU Hua-Guang, Liu Zhi-Qiang, REN Wei. [The modulation of 4-aminopyridine sensitive potassium channel to bifurcationscenario of the spontaneous neural firing rhythms.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (1): 35-41 (in Chinese with English abstract).