TITLE Calcium dependent potassium channel
: Implemented in Rubin and Cleland, J. Neurophysiol 2006
: KCa channel with parameters from US Bhalla and JM Bower,
: J. Neurophysiol. 69:19481983 (1993)
: Adapted from /usr/local/neuron/demo/release/nachan.mod  squid
: by Andrew Davison, The Babraham Institute.
: 240898
: Modified by GL !!!
NEURON {
SUFFIX Ikca
USEION k READ ek WRITE ik
USEION ca READ cai
RANGE gkbar, ik, Yconcdep, Yvdep
GLOBAL Yalpha, Ybeta
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
(molar) = (1/liter)
(mM) = (millimolar)
}
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
PARAMETER {
v (mV)
dt (ms)
gkbar= 0.120 (mho/cm2) <0,1e9>
ek = 80 (mV)
Ybeta = 0.05 (/ms)
cai (mM) := 1e5 (mM)
}
STATE {
Y
}
ASSIGNED {
ik (mA/cm2)
Yalpha (/ms)
Yvdep
Yconcdep (/ms)
}
INITIAL {
rate(v,cai)
Y = Yalpha/(Yalpha + Ybeta)
}
BREAKPOINT {
SOLVE state METHOD cnexp
ik = gkbar*Y*(v  ek)
}
DERIVATIVE state {
rate(v,cai)
Y' = Yalpha*(1Y)  Ybeta*Y
}
PROCEDURE rate(v(mV),cai(mM)) {
vdep(v)
concdep(cai)
Yalpha = Yvdep*Yconcdep
}
PROCEDURE vdep(v(mV)) {
TABLE Yvdep FROM 100 TO 100 WITH 100
Yvdep = exp((v*1(/mV)65)/27) : exp((v*1(/mV)+70)/27)
}
PROCEDURE concdep(cai(mM)) {
TABLE Yconcdep FROM 0 TO 50 WITH 2000
if ( fabs(cai0.015) < 1e5) {
Yconcdep = 500(/ms)/(1/0.0013 + 0.5*(0.015cai)/0.0013^2 )
:Yconcdep = 500(/ms)*( 0.015cai*1(/mM) )/( exp((0.015cai*1(/mM))/0.0013) 1 )
} else {
Yconcdep = 500(/ms)*( 0.015cai*1(/mM) )/( exp((0.015cai*1(/mM))/0.0013) 1 )
:Yconcdep = 500(/ms)*0.005/( exp(0.005/0.0013) 1 )
}
}
