TITLE Cerebellum Granule Cell Model COMMENT KDr channel Gutfreund parametrization Author: A. Fontana Last revised: 12.12.98 ENDCOMMENT NEURON { SUFFIX GRC_KV USEION k READ ek WRITE ik RANGE gkbar, ik, g, alpha_n, beta_n RANGE Aalpha_n, Kalpha_n, V0alpha_n RANGE Abeta_n, Kbeta_n, V0beta_n RANGE n_inf, tau_n } UNITS { (mA) = (milliamp) (mV) = (millivolt) } PARAMETER { :Kbeta_n = -0.0125 (/mV) Aalpha_n = -0.01 (/ms-mV) Kalpha_n = -10 (mV) V0alpha_n = -25 (mV) Abeta_n = 0.125 (/ms) Kbeta_n = -80 (mV) V0beta_n = -35 (mV) v (mV) gkbar= 0.003 (mho/cm2) : 0.0015 ek = -84.69 (mV) celsius = 30 (degC) } STATE { n } ASSIGNED { ik (mA/cm2) n_inf tau_n (ms) g (mho/cm2) alpha_n (/ms) beta_n (/ms) } INITIAL { rate(v) n = n_inf } BREAKPOINT { SOLVE states METHOD derivimplicit g = gkbar*n*n*n*n ik = g*(v - ek) alpha_n = alp_n(v) beta_n = bet_n(v) } DERIVATIVE states { rate(v) n' =(n_inf - n)/tau_n } FUNCTION alp_n(v(mV))(/ms) { LOCAL Q10 Q10 = 3^((celsius-6.3(degC))/10(degC)) alp_n = Q10*Aalpha_n*linoid(v-V0alpha_n, Kalpha_n) } FUNCTION bet_n(v(mV))(/ms) { LOCAL Q10 Q10 = 3^((celsius-6.3(degC))/10(degC)) bet_n = Q10*Abeta_n*exp((v-V0beta_n)/Kbeta_n) } PROCEDURE rate(v (mV)) {LOCAL a_n, b_n TABLE n_inf, tau_n DEPEND Aalpha_n, Kalpha_n, V0alpha_n, Abeta_n, Kbeta_n, V0beta_n, celsius FROM -100 TO 30 WITH 13000 a_n = alp_n(v) b_n = bet_n(v) tau_n = 1/(a_n + b_n) n_inf = a_n/(a_n + b_n) } FUNCTION linoid(x (mV),y (mV)) (mV) { if (fabs(x/y) < 1e-6) { linoid = y*(1 - x/y/2) }else{ linoid = x/(exp(x/y) - 1) } }