TITLE ichan2.mod
COMMENT
konduktivitas valtozas hatasa- somaban
ENDCOMMENT
UNITS {
(mA) =(milliamp)
(mV) =(millivolt)
(uF) = (microfarad)
(molar) = (1/liter)
(nA) = (nanoamp)
(mM) = (millimolar)
(um) = (micron)
FARADAY = 96520 (coul)
R = 8.3134 (joule/degC)
}
? interface
NEURON {
SUFFIX ichan2
USEION nat READ enat WRITE inat VALENCE 1
USEION kf READ ekf WRITE ikf VALENCE 1
USEION ks READ eks WRITE iks VALENCE 1
NONSPECIFIC_CURRENT il
RANGE gnat, gkf, gks
RANGE gnatbar, gkfbar, gksbar
RANGE gl, el
RANGE minf, mtau, hinf, htau, nfinf, nftau, inat, ikf, nsinf, nstau, iks
}
INDEPENDENT {t FROM 0 TO 100 WITH 100 (ms)}
PARAMETER {
v (mV)
celsius = 6.3 (degC)
dt (ms)
enat (mV)
gnatbar (mho/cm2)
ekf (mV)
gkfbar (mho/cm2)
eks (mV)
gksbar (mho/cm2)
gl (mho/cm2)
el (mV)
}
STATE {
m h nf ns
}
ASSIGNED {
gnat (mho/cm2)
gkf (mho/cm2)
gks (mho/cm2)
inat (mA/cm2)
ikf (mA/cm2)
iks (mA/cm2)
il (mA/cm2)
minf hinf nfinf nsinf
mtau (ms) htau (ms) nftau (ms) nstau (ms)
mexp hexp nfexp nsexp
}
? currents
BREAKPOINT {
SOLVE states
gnat = gnatbar*m*m*m*h
inat = gnat*(v - enat)
gkf = gkfbar*nf*nf*nf*nf
ikf = gkf*(v-ekf)
gks = gksbar*ns*ns*ns*ns
iks = gks*(v-eks)
il = gl*(v-el)
}
UNITSOFF
INITIAL {
trates(v)
m = minf
h = hinf
nf = nfinf
ns = nsinf
VERBATIM
return;
ENDVERBATIM
}
? states
PROCEDURE states() { :Computes state variables m, h, and n
trates(v) : at the current v and dt.
m = m + mexp*(minf-m)
h = h + hexp*(hinf-h)
nf = nf + nfexp*(nfinf-nf)
ns = ns + nsexp*(nsinf-ns)
VERBATIM
return 0;
ENDVERBATIM
}
LOCAL q10
? rates
PROCEDURE rates(v) { :Computes rate and other constants at current v.
:Call once from HOC to initialize inf at resting v.
LOCAL alpha, beta, sum
:q10 = 3^((celsius - 6.3)/10)
q10 = 1 : make temperature independent (BPG)
:"m" sodium activation system - act and inact cross at -40
alpha = -0.3*vtrap((v+60-17),-5)
beta = 0.3*vtrap((v+60-45),5)
sum = alpha+beta
mtau = 1/sum minf = alpha/sum
:"h" sodium inactivation system
alpha = 0.23/exp((v+60+5)/20)
beta = 3.33/(1+exp((v+60-47.5)/-10))
sum = alpha+beta
htau = 1/sum
hinf = alpha/sum
:"ns" sKDR activation system
alpha = -0.028*vtrap((v+65-35),-6)
beta = 0.1056/exp((v+65-10)/40)
sum = alpha+beta
nstau = 1/sum nsinf = alpha/sum
:"nf" fKDR activation system
alpha = -0.07*vtrap((v+65-47),-6)
beta = 0.264/exp((v+65-22)/40)
sum = alpha+beta
nftau = 1/sum nfinf = alpha/sum
}
PROCEDURE trates(v) { :Computes rate and other constants at current v.
:Call once from HOC to initialize inf at resting v.
LOCAL tinc
TABLE minf, mexp, hinf, hexp, nfinf, nfexp, nsinf, nsexp, mtau, htau, nftau, nstau
DEPEND dt, celsius FROM -100 TO 100 WITH 200
rates(v) : not consistently executed from here if usetable_hh == 1
: so don't expect the tau values to be tracking along with
: the inf values in hoc
tinc = -dt * q10
mexp = 1 - exp(tinc/mtau)
hexp = 1 - exp(tinc/htau)
nfexp = 1 - exp(tinc/nftau)
nsexp = 1 - exp(tinc/nstau)
}
FUNCTION vtrap(x,y) { :Traps for 0 in denominator of rate eqns.
if (fabs(x/y) < 1e-6) {
vtrap = y*(1 - x/y/2)
}else{
vtrap = x/(exp(x/y) - 1)
}
}
UNITSON
| 
