TITLE Kct current
COMMENT Equations from
Shao L.R., Halvorsrud R., Borg-Graham L., Storm J.F. The role of BK-type Ca2_-dependent K+ channels in spike broadening during repetitive firing in rat hippocampal pyramidal cells J.Physiology (1999),521:135-146
The Krasnow Institute
George Mason University
Copyright Maciej Lazarewicz, 2001
(mlazarew@gmu.edu)
All rights reserved.
ENDCOMMENT
NEURON {
:SUFFIX mykca
SUFFIX kctin
USEION k READ ek WRITE ik
USEION ca READ cai
RANGE gkcbar,ik
}
UNITS {
(molar) = (1/liter)
(mM) = (millimolar)
(S) = (siemens)
(mA) = (milliamp)
(mV) = (millivolt)
}
PARAMETER {
gkcbar = 0 (S/cm2)
:gkbar = 1.0e-3 (S/cm2)
}
ASSIGNED {
v (mV)
cai (mM) :26/10/04 htan se sxolio
celsius (degC)
ek (mV)
ik (mA/cm2)
k1 (/ms)
k2 (/ms)
k3 (/ms)
k4 (/ms)
q10 (1)
}
STATE { cst ost ist }
BREAKPOINT {
SOLVE kin METHOD sparse
ik = gkcbar * ost *( v - ek )
}
INITIAL {
SOLVE kin STEADYSTATE sparse
}
KINETIC kin {
: rates(v, cani)
rates(v, cai)
~cst<->ost (k3,k4)
~ost<->ist (k1,0.0)
~ist<->cst (k2,0.0)
CONSERVE cst+ost+ist=1
}
:change feb8th for pfc
:PROCEDURE rates( v(mV), cani(mM)) {
PROCEDURE rates( v(mV), cai(mM)) {
: k1=alp( 0.1, v, -10.0, 1.0 ) : original
k1=alp( 0.01, v, -10.0, 1.0 ) :increases the current
k2=alp( 0.1, v, -120.0, -10.0 ) :original (0.1, -120, -10)
: k3=alpha( 0.001, 1.0, v, -20.0, 7.0 ) *1.0e8* ( cai*1.0(/mM) )^3 :original
k3=alpha( 0.001, 1.0, v, -20.0, 7.0 ) *1.0e8* (cai*1.0(/mM) )^3
:k3 changes the attenuation
k4=alp( 0.2, v, -44.0, -5.0 ) :original
: k4=alp( 0.2, v, -44.0, -5.0 )
}
FUNCTION alpha( tmin(ms), tmax(ms), v(mV), vhalf(mV), k(mV) )(/ms){
alpha = 1.0 / ( tmin + 1.0 / ( 1.0 / (tmax-tmin) + exp((v-vhalf)/k)*1.0(/ms) ) )
}
FUNCTION alp( tmin(ms), v(mV), vhalf(mV), k(mV) )(/ms){
alp = 1.0 / ( tmin + exp( -(v-vhalf) / k )*1.0(ms) )
}