TITLE K-A channel from Klee Ficker and Heinemann : modified to account for Dax A Current ---------- : M.Migliore Jun 1997 NEURON { SUFFIX kap USEION k READ ek WRITE ik RANGE gkabar,gka,ik RANGE ninf,linf,taul,taun RANGE vhalfn,vhalfl GLOBAL lmin,nscale,lscale } UNITS { (mA) = (milliamp) (mV) = (millivolt) (mol) = (1) } PARAMETER { temp = 24 (degC) gkabar (mho/cm2) vhalfn = 11 (mV) a0n = 0.05 (/ms) zetan = -1.5 (1) gmn = 0.55 (1) pw = -1 (1) tq = -40 (mV) qq = 5 (mV) nmin = 0.1 (ms) nscale = 1 vhalfl = -56 (mV) a0l = 0.05 (/ms) zetal = 3 (1) lmin = 2 (ms) lscale = 1 q10 = 5 } STATE { n l } ASSIGNED { v (mV) ik (mA/cm2) ninf linf taul (ms) taun (ms) gka (mho/cm2) qt celsius (degC) ek (mV) } INITIAL { rates(v) n=ninf l=linf } BREAKPOINT { SOLVE states METHOD cnexp gka = gkabar*n*l ik = gka*(v-ek) } DERIVATIVE states { rates(v) n' = (ninf-n)/taun l' = (linf-l)/taul } FUNCTION alpn(v(mV)) { LOCAL zeta zeta=zetan+pw/(1+exp((v-tq)/qq)) alpn = exp(zeta*(v-vhalfn)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius))) } FUNCTION betn(v(mV)) { LOCAL zeta zeta=zetan+pw/(1+exp((v-tq)/qq)) betn = exp(zeta*gmn*(v-vhalfn)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius))) } FUNCTION alpl(v(mV)) { alpl = exp(zetal*(v-vhalfl)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius))) } FUNCTION betl(v(mV)) { betl = exp(zetal*(v-vhalfl)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius))) } PROCEDURE rates(v (mV)) { :callable from hoc LOCAL a,qt qt=q10^((celsius-temp)/10(degC)) a = alpn(v) ninf = 1/(1 + a) taun = betn(v)/(qt*a0n*(1+a)) if (taun