:Migliore file Modify by Maciej Lazarewicz (mailto:mlazarew@gmu.edu) May/16/2001
TITLE Borg-Graham type generic K-AHP channel
NEURON {
SUFFIX KahpM95
USEION k READ ek WRITE ik
USEION ca READ cai
RANGE gbar,ik, gkahp
GLOBAL inf,tau
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
}
PARAMETER {
celsius = 6.3 (degC)
gbar = .003 (mho/cm2)
n = 4
cai = 50.e-6 (mM)
a0 = 1e8 (/ms-mM-mM-mM-mM) :b0/(20e-4^4)
b0 = .5e-2 (/ms) :0.5/(0.100e3)
v (mV)
ek (mV)
q10=3
}
STATE { w }
ASSIGNED {
ik (mA/cm2)
gkahp (mho/cm2)
inf
tau
}
BREAKPOINT {
SOLVE state METHOD cnexp
gkahp = gbar*w
ik = gkahp*(v-ek)
}
INITIAL {
rate(cai)
w=inf
}
FUNCTION alp(cai (mM)) {
alp = a0*cai^n
}
DERIVATIVE state { : exact when v held constant; integrates over dt step
rate(cai)
w' = (inf - w)/tau
}
PROCEDURE rate(cai (mM)) { :callable from hoc
LOCAL a,qt
qt=q10^((celsius-24)/10)
a = alp(cai)
tau = 1/(qt*(a + b0))
inf = a*tau*qt
}