TITLE KA
: K-A current for hippocampal interneurons from Lien et al (2002)
: M.Migliore Jan. 2003
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
}
NEURON {
SUFFIX Ika
USEION k READ ek WRITE ik
RANGE gbar, ik
GLOBAL minf, hinf, htau, mtau
}
PARAMETER {
gbar = 0.0002 (mho/cm2)
celsius (degC)
ek (mV) : must be explicitly def. in hoc
v (mV)
a0h=0.17
vhalfh=-105 (mV)
q10=3
hmin=5 (ms)
}
ASSIGNED {
ik (mA/cm2)
minf
mtau (ms)
hinf
htau (ms)
}
INITIAL {
trates(v)
m=minf
h=hinf
}
STATE {m h}
BREAKPOINT {
SOLVE state METHOD cnexp
ik = gbar*m*h*(v - ek)
}
DERIVATIVE state {
trates(v)
m' = (minf-m)/mtau
h' = (hinf-h)/htau
}
PROCEDURE trates(v(mV)) {
LOCAL qt
qt=q10^((celsius-23(degC))/10(degC))
minf = (1/(1 + exp(-(v+41.4(mV))/26.6(mV))))^4
mtau=0.5(ms)/qt
hinf = 1/(1 + exp((v+78.5(mV))/6(mV)))
htau = a0h*1(ms/mV)*(v-vhalfh)/qt
if (htau<hmin/qt) {htau=hmin/qt}
}