TITLE Calcium dependent nonspecific cation channel
NEURON {
SUFFIX Ican
NONSPECIFIC_CURRENT i
USEION ca READ cai
RANGE gbar, i, minf, tauinf, m, cai, g, MCa, mm, Shm
GLOBAL tauca
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
(molar) = (1/liter)
(mM) = (millimolar)
(uM) = (micromolar)
}
PARAMETER {
v (mV)
dt (ms)
gbar= 0.003 (mho/cm2) <0,1e9>
e = 10 (mV)
tauca = 800 (ms)
kdcan = .200 (mM)
Shm = 2
}
STATE {
m
g (mho/cm2)
MCa
mm
}
ASSIGNED {
cai (mM)
i (mA/cm2)
minf
tauinf (ms)
}
INITIAL {
rate(v)
m = minf
}
BREAKPOINT {
SOLVE state METHOD cnexp
MCa = (cai/(kdcan + cai)) : different ways to read out all the different gating variables
mm = m*MCa
g = gbar*mm
i = g*(v  e)
}
DERIVATIVE state {
rate(v)
m' = (minf m)/tauinf
}
PROCEDURE rate(v(mV)) {
UNITSOFF
minf = 1/(1+exp((43+vShm)/5.2))
tauinf = 1.6 + 2.7 /(exp((55v)/15) + exp((55v)/(15)))
UNITSON
}
