TITLE ikdrs :Delayed rectifier potassium current in the interneuron soma NEURON { SUFFIX ikdrs USEION k READ ek WRITE ik RANGE gkdr, gk, ik, qk } UNITS { (molar) = (1/liter) (mV) = (millivolt) (mA) = (milliamp) (mM) = (millimolar) FARADAY = 96485.309 (coul/mole) PI = (pi) (1) } INDEPENDENT {t FROM 0 TO 1 WITH 100 (ms)} PARAMETER { gkdr=1e-3 (mho/cm2) } ASSIGNED { ik (mA/cm2) v (mV) ek (mV) gk (mho/cm2) diam (um) ki (mM) } STATE { n c qk } BREAKPOINT { SOLVE kstate METHOD sparse gk = gkdr*n*n*n*n ik = gk*(v-ek) } INITIAL { n=n_inf(v) c=1-n gk = gkdr*n*n*n*n ik = gk*(v-ek) qk=0 } LOCAL a1, a2 KINETIC kstate { a1 = a_n(v) a2 = a_c(v) ~ c <-> n (a1, a2) CONSERVE n + c = 1 COMPARTMENT diam*diam*PI/4 { qk } ~ qk << (-ik*diam*PI*(1e4)/FARADAY ) } FUNCTION a_n(v(mV)) { TABLE FROM -150 TO 150 WITH 200 a_n = n_inf(v)/tau_act(v) } FUNCTION a_c(v(mV)) { TABLE FROM -150 TO 150 WITH 200 a_c = (1-n_inf(v))/tau_act(v) } FUNCTION n_inf(v(mV)) { n_inf = 1/(1+exp((-4.8-v-30)/13.6)) } FUNCTION tau_act(v(mV)) { tau_act = 1.6/(0.0338338*exp(-v/40)+(0.016*exp(v/5)*(64.9+v))/(-0.00000230599+exp(v/5))) }