TITLE Slow Ca-dependent potassium current : : Ca++ dependent K+ current responsible for slow AHP NEURON { SUFFIX kca USEION k READ ko, ki WRITE ik USEION ca READ cai RANGE gbar, po, ik GLOBAL m_inf, tau_m } UNITS { (mA) = (milliamp) (mV) = (millivolt) (molar) = (1/liter) (mM) = (millimolar) } ASSIGNED { : parameters needed to solve DE v (mV) celsius (degC) ek (mV) cai (mM) : initial [Ca]i ik (mA/cm2) po ki (mM) ko (mM) m_inf tau_m (ms) : h_inf :inactivation : tau_h (ms) : taumin } PARAMETER { gbar = 10 (mho/cm2) : ek (mV) taumin = 0 (ms) :(150) b = 0.008 (/ms) : changed oct 17, 2006 for pfc (0.3) :b = 0.8 : value for CA1 neuron(2006) : tau_h = 300 (ms) } STATE { m } BREAKPOINT { SOLVE states METHOD cnexp ek = 25 * log(ko/ki) po = m*m ik = gbar*po*(v - ek) : potassium current induced by this channel } DERIVATIVE states { rates(cai) : m'=(-1/(tau_m))*(m-(m_inf)) m' = (m_inf - m) / tau_m : old equation : h'=(h_inf - h)/tau_h } INITIAL { rates(cai) m = 0 : m = m_inf : h = h_inf } PROCEDURE rates(cai(mM)) { LOCAL a : a=100 : m_inf=(a*cai*cai)/(a*cai*cai+b) : tau_m=(1/(a*cai*cai+b)) :old equations a = cai/b m_inf = a/(a+1) : tau_m=600 tau_m = taumin+ 1(ms)*1(mM)*b/(cai+b) :inactivation : h_inf= ah/(ah+1) }