COMMENT kca.mod Calcium-dependent potassium channel Based on Pennefather (1990) -- sympathetic ganglion cells taken from Reuveni et al (1993) -- neocortical cells Author: Zach Mainen, Salk Institute, 1995, zach@salk.edu Kole: the caix increased from 1 -> 4, Ra 0.01 to 0.05 and Rb 0.02 to 0.1, according to Schaefer et al, 2003 to allow BAC firing ENDCOMMENT INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} NEURON { SUFFIX kca USEION k READ ek WRITE ik USEION ca READ cai RANGE n, gkca, ikca, gbar RANGE ninf, ntau GLOBAL Ra, Rb, caix GLOBAL q10, temp, tadj, vmin, vmax } UNITS { (mA) = (milliamp) (mV) = (millivolt) (pS) = (picosiemens) (um) = (micron) } PARAMETER { gbar = 10 (pS/um2) : 0.03 mho/cm2 v (mV) cai (mM) caix = 4 Ra = 0.05 (/ms) : max act rate Rb = 0.1 (/ms) : max deact rate dt (ms) celsius (degC) temp = 23 (degC) : original temp q10 = 2.3 : temperature sensitivity vmin = -120 (mV) vmax = 100 (mV) } ASSIGNED { a (/ms) b (/ms) ik (mA/cm2) ikca (mA/cm2) gkca (pS/um2) ek (mV) ninf ntau (ms) tadj } STATE { n } INITIAL { rates(cai) n = ninf } BREAKPOINT { SOLVE states METHOD cnexp gkca =gbar*n ikca = (1e-4) * gkca * (v - ek) ik = ikca } LOCAL nexp DERIVATIVE states { :Computes state variable n rates(cai) : at the current v and dt. n' = (ninf-n)/ntau } PROCEDURE rates(cai(mM)) { a = Ra * cai^caix b = Rb tadj = q10^((celsius - temp)/10) ntau = 1/tadj/(a+b) ninf = a/(a+b) : tinc = -dt * tadj : nexp = 1 - exp(tinc/ntau) }