TITLE Cerebellum Granule Cell Model COMMENT KCa channel Author: E.D'Angelo, T.Nieus, A. Fontana Last revised: 8.5.2000 ENDCOMMENT NEURON { SUFFIX GRC_KCA USEION k READ ek WRITE ik USEION ca READ cai RANGE gkbar, ik, ica, g, alpha_c, beta_c RANGE Aalpha_c, Balpha_c, Kalpha_c RANGE Abeta_c, Bbeta_c, Kbeta_c RANGE c_inf, tau_c } UNITS { (mA) = (milliamp) (mV) = (millivolt) (molar) = (1/liter) (mM) = (millimolar) } PARAMETER { Aalpha_c = 2.5 (/ms) Balpha_c = 1.5e-3 (mM) :Kalpha_c = -0.085 (/mV) Kalpha_c = -11.765 (mV) Abeta_c = 1.5 (/ms) Bbeta_c = 0.15e-3 (mM) :Kbeta_c = -0.085 (/mV) Kbeta_c = -11.765 (mV) v (mV) cai (mM) gkbar= 0.003 (mho/cm2) ek = -84.69 (mV) celsius = 30 (degC) } STATE { c } ASSIGNED { ik (mA/cm2) ica (mA/cm2) c_inf tau_c (ms) g (mho/cm2) alpha_c (/ms) beta_c (/ms) } INITIAL { rate(v) c = c_inf } BREAKPOINT { SOLVE states METHOD derivimplicit g = gkbar*c ik = g*(v - ek) alpha_c = alp_c(v) beta_c = bet_c(v) } DERIVATIVE states { rate(v) c' =(c_inf - c)/tau_c } FUNCTION alp_c(v(mV))(/ms) { LOCAL Q10 Q10 = 3^((celsius-30(degC))/10(degC)) alp_c = Q10*Aalpha_c/(1+(Balpha_c*exp(v/Kalpha_c)/cai)) } FUNCTION bet_c(v(mV))(/ms) { LOCAL Q10 Q10 = 3^((celsius-30(degC))/10(degC)) bet_c = Q10*Abeta_c/(1+cai/(Bbeta_c*exp(v/Kbeta_c))) } PROCEDURE rate(v (mV)) {LOCAL a_c, b_c TABLE c_inf, tau_c DEPEND Aalpha_c, Balpha_c, Kalpha_c, Abeta_c, Bbeta_c, Kbeta_c, celsius FROM -100 TO 30 WITH 13000 a_c = alp_c(v) b_c = bet_c(v) tau_c = 1/(a_c + b_c) c_inf = a_c/(a_c + b_c) }