optimize_cells/kad.mod at master · neurosutras/optimize_cells · GitHub

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TITLE K-A channel from Klee Ficker and Heinemann
: modified to account for Dax A Current ----------
: M.Migliore Jun 1997

NEURON {
	SUFFIX kad
	USEION k READ ek WRITE ik
    RANGE gkabar,gka,ik
    RANGE ninf,linf,taul,taun
    RANGE vhalfn,vhalfl
    GLOBAL lmin,nscale,lscale
}

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
	(mS) = (millisiemens)
    (mol) = (1)
}

PARAMETER {
    temp    =   24			(degC)

    gkabar  			(mho/cm2)

    vhalfn  =   -1			(mV)
    a0n     =   .1			(/ms)
    zetan   = -1.8			(1)
    gmn     = 0.39			(1)
    pw      =   -1			(1)
    tq      =  -40			(mV)
    qq      =    5			(mV)
    nmin    =  0.1			(ms)
    nscale  =    1

    vhalfl  =  -56 			(mV)
    a0l     = 0.05			(/ms)
    zetal   =    3			(1)
    lmin    =    2			(ms)
    lscale  =    1

    q10     =    5
    qtl     =    1
    gml     =    1			(1)
}

STATE {
	n
    l
}

ASSIGNED {
	v		    (mV)
    ik          (mA/cm2)
    ninf
    linf
    taul        (ms)
    taun        (ms)
    gka         (mho/cm2)
    qt
    celsius     (degC)
    ek          (mV)
}

INITIAL {
    rates(v)
    n=ninf
    l=linf
}

BREAKPOINT {
	SOLVE states METHOD cnexp
	gka = gkabar*n*l
	ik = gka*(v-ek)
}

DERIVATIVE states {
    rates(v)
    n' = (ninf-n)/taun
    l' = (linf-l)/taul
}

FUNCTION alpn(v(mV)) {
    LOCAL zeta
    zeta=zetan+pw/(1+exp((v-tq)/qq))
    alpn = exp(zeta*(v-vhalfn)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius)))
}

FUNCTION betn(v(mV)) {
    LOCAL zeta
    zeta=zetan+pw/(1+exp((v-tq)/qq))
    betn = exp(zeta*gmn*(v-vhalfn)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius)))
}

FUNCTION alpl(v(mV)) {
    alpl = exp(zetal*(v-vhalfl)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius)))
}

FUNCTION betl(v(mV)) {
    betl = exp(zetal*gml*(v-vhalfl)*1.e-3(V/mV)*9.648e4(coulomb/mol)/(8.315(joule/mol/degC)*(273.16(degC)+celsius)))
}

PROCEDURE rates(v (mV)) { :callable from hoc
    LOCAL a,qt
    qt=q10^((celsius-temp)/10(degC))
    a = alpn(v)
    ninf = 1/(1 + a)
    taun = betn(v)/(qt*a0n*(1+a))
	if (taun<nmin) {taun=nmin}
    taun = taun/nscale

    a = alpl(v)
    linf = 1/(1+ a)
	taul = 0.26(ms/mV)*(v+50)/qtl
	if (taul<lmin/qtl) {taul=lmin/qtl}
    taul = taul/lscale
}