TITLE HH Ttype calcium channel
NEURON {
SUFFIX Icat
USEION ca WRITE ica
RANGE gbar, ica, g, h, m, sha, shi, k_tauH
GLOBAL minf, hinf, mtau, htau
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
}
PARAMETER {
v (mV)
gbar = 0.036 (mho/cm2) <0,1e9>
e = 100 (mV)
sha = 0
shi = 0
k_tauH = 1
}
STATE {
m
h
g (mho/cm2)
}
ASSIGNED {
ica (mA/cm2)
minf
hinf
mtau (ms)
htau (ms)
}
INITIAL {
rates(v)
m = minf
h = hinf
}
BREAKPOINT {
SOLVE states METHOD cnexp
g = gbar*m*m*h
ica = g*(v  e)
}
DERIVATIVE states {
: computes state variables m and h at present v, t
rates(v)
m' = (minf  m)/mtau
h' = (hinf  h)/htau
}
PROCEDURE rates(v(mV)) {
UNITSOFF
mtau = 1.5 + 3.5/(exp((v+30sha)/15) + exp((v+30sha)/(15)))
minf = 1/(1+exp((v+44sha)/5.5))
htau = 10 + 40/(exp((v+50shi)/15) + exp((v+50shi)/(15)))
hinf = k_tauH*1/(1+exp((v+70shi)/(4)))
UNITSON
}
