Role of calcium conductance in firing behavior of retinal ganglion cells  

作　　者：Wang, Dan Qiao, Qingli Xie, Nan 

机构地区：[1]Tianjin Med Univ, Sch Biomed Engn, Tianjin 300070, Peoples R China

出　　处：《Neural Regeneration Research》2011年第3期231-235,共5页中国神经再生研究（英文版）

基　　金：the National Natural Science Foundation of China,No. 30870649;Science and Technology 973 Project,No. 2005CB724302

摘　　要：Fohlmeister-Coleman-Miller model of retinal ganglion cells consists of five ion channels; these are sodium channels, calcium channels, and 3 types of potassium channels. An increasing number of studies have investigated sodium channels, voltage-gated potassium channels, and delayed rectifier potassium channels. However, little is known about calcium channels, and in particular the dynamics and computational models of calcium ions. Retinal prostheses have been designed to assist with sight recovery for the blind, and in the present study, the effects of calcium ions in retinal ganglion cell models were analyzed with regard to calcium channel potential and calcium-activated potassium potential. Using MATLAB software, calcium conductance and calcium current from the Fohlmeister-Coleman-Miller model, under clamped voltages, were numerically computed using backward Euler methods. Subsequently, the Fohlmeister-Coleman-Miller model was simulated with the absence of calcium-current （lca） or calcium-activated potassium current （lK, Ca）. The model was also analyzed according to the phase plane method. The relationship curve between peak calcium current and clamped potentials revealed an inverted bell shape, and the calcium-activated potassium current increased the frequency of firing and the peak of membrane potential. Results suggested that calcium ion concentrations play an important role in controlling the peak and the magnitude of peak membrane voltage in retinal ganglion cells.Fohlmeister-Coleman-Miller model of retinal ganglion cells consists of five ion channels; these are sodium channels, calcium channels, and 3 types of potassium channels. An increasing number of studies have investigated sodium channels, voltage-gated potassium channels, and delayed rectifier potassium channels. However, little is known about calcium channels, and in particular the dynamics and computational models of calcium ions. Retinal prostheses have been designed to assist with sight recovery for the blind, and in the present study, the effects of calcium ions in retinal ganglion cell models were analyzed with regard to calcium channel potential and calcium-activated potassium potential. Using MATLAB software, calcium conductance and calcium current from the Fohlmeister-Coleman-Miller model, under clamped voltages, were numerically computed using backward Euler methods. Subsequently, the Fohlmeister-Coleman-Miller model was simulated with the absence of calcium-current （lca） or calcium-activated potassium current （lK, Ca）. The model was also analyzed according to the phase plane method. The relationship curve between peak calcium current and clamped potentials revealed an inverted bell shape, and the calcium-activated potassium current increased the frequency of firing and the peak of membrane potential. Results suggested that calcium ion concentrations play an important role in controlling the peak and the magnitude of peak membrane voltage in retinal ganglion cells.

关 键 词：action potential calcium conductance computational neuron model Fohlmeister-Coleman-Miller model retinal ganglion cell 

分 类 号：Q463[生物学—生理学] TP311.56[自动化与计算机技术—计算机软件与理论]