:Kv4 CSI Markov model from Fineberg, Ritter and Covarrubias J Gen Physiol (2012)
:for scheme see Fig. S1 and Table S1 or file "IonChannelLab Files/Kv4 CSI.ichl"
:based on Amarillo et al. J Physiol (2008) and Migliore et al J Comp Neurosci (1999)
:last edited 10-06-2012 by DMR
NEURON {
SUFFIX kv4csi
USEION k READ ek WRITE ik
RANGE g, gmax
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
}
PARAMETER {
gmax = 0.00 (mho/cm2)
celsius (deg C)
F = 9.6485e4 :Faraday constant
R = 8.3145e3 :Gas constant
a = 7 (/ms) :alpha transitions
za = 0.315646648
b = .090 (/ms) :beta transitions
zb = -2.062276
c = 1.01216107 (/ms) :gamma transition
zc = 0.500095665
d = 2.498881 (/ms) :delta transition
zd = -1.1546687
k = 7.69049072 (/ms) :epsilon transition
zk = 0.05502051
l = 4.38562354 (/ms) :phi transition
zl = -0.07092366
f = 0.277130485 :closed-state inactivation allosteric factor f
q = 1.01314807 :closed-state inactivation allosteric factor g
kci = 0.121900093 (/ms) :closed to inactivated transitions
kic = 0.0017935468 (/ms) :inactivated to closed transitions
}
ASSIGNED {
v (mV)
ek (mV)
g (S/cm2)
ik (mA/cm2)
kC01f (/ms)
kC01b (/ms)
kC12f (/ms)
kC12b (/ms)
kC23f (/ms)
kC23b (/ms)
kC34f (/ms)
kC34b (/ms)
kC45f (/ms)
kC45b (/ms)
kCOf (/ms)
kCOb (/ms)
kCI0f (/ms)
kCI0b (/ms)
kCI1f (/ms)
kCI1b (/ms)
kCI2f (/ms)
kCI2b (/ms)
kCI3f (/ms)
kCI3b (/ms)
kCI4f (/ms)
kCI4b (/ms)
kCI5f (/ms)
kCI5b (/ms)
kI01f (/ms)
kI01b (/ms)
kI12f (/ms)
kI12b (/ms)
kI23f (/ms)
kI23b (/ms)
kI34f (/ms)
kI34b (/ms)
kI45f (/ms)
kI45b (/ms)
}
STATE { C0 C1 C2 C3 C4 C5 I0 I1 I2 I3 I4 I5 O }
BREAKPOINT {
SOLVE states METHOD sparse
g = gmax * O
ik = g * (v - ek)
}
INITIAL { SOLVE states STEADYSTATE sparse}
KINETIC states {
rates(v)
~C0 <-> C1 (kC01f,kC01b)
~C1 <-> C2 (kC12f,kC12b)
~C2 <-> C3 (kC23f,kC23b)
~C3 <-> C4 (kC34f,kC34b)
~C4 <-> C5 (kC45f,kC45b)
~C5 <-> O (kCOf,kCOb)
~C0 <-> I0 (kCI0f,kCI0b)
~C1 <-> I1 (kCI1f,kCI1b)
~C2 <-> I2 (kCI2f,kCI2b)
~C3 <-> I3 (kCI3f,kCI3b)
~C4 <-> I4 (kCI4f,kCI4b)
~C5 <-> I5 (kCI5f,kCI5b)
~I0 <-> I1 (kI01f,kI01b)
~I1 <-> I2 (kI12f,kI12b)
~I2 <-> I3 (kI23f,kI23b)
~I3 <-> I4 (kI34f,kI34b)
~I4 <-> I5 (kI45f,kI45b)
CONSERVE C0+C1+C2+C3+C4+C5+I0+I1+I2+I3+I4+I5+O=1
}
PROCEDURE rates(v(millivolt)) {
kC01f = 4*a*exp(za*v*F/(R*(273.16+celsius))) :closed to open pathway transitions
kC01b = b*exp(zb*v*F/(R*(273.16+celsius)))
kC12f = 3*a*exp(za*v*F/(R*(273.16+celsius)))
kC12b = 2*b*exp(zb*v*F/(R*(273.16+celsius)))
kC23f = 2*a*exp(za*v*F/(R*(273.16+celsius)))
kC23b = 3*b*exp(zb*v*F/(R*(273.16+celsius)))
kC34f = a*exp(za*v*F/(R*(273.16+celsius)))
kC34b = 4*b*exp(zb*v*F/(R*(273.16+celsius)))
kC45f = c*exp(zc*v*F/(R*(273.16+celsius)))
kC45b = d*exp(zd*v*F/(R*(273.16+celsius)))
kCOf = k*exp(zk*v*F/(R*(273.16+celsius)))
kCOb = l*exp(zl*v*F/(R*(273.16+celsius)))
kCI0f = kci*(f^4) :closed to inactivated transitions
kCI0b = kic/(f^4)
kCI1f = kci*(f^3)
kCI1b = kic/(f^3)
kCI2f = kci*(f^2)
kCI2b = kic/(f^2)
kCI3f = kci*(f)
kCI3b = kic/(f)
kCI4f = kci
kCI4b = kic
kCI5f = kci*q
kCI5b = kic/q
kI01f = 4*(1/f)*a*exp(za*v*F/(R*(273.16+celsius))) :closed to inactivated transitions
kI01b = d*b*exp(zb*v*F/(R*(273.16+celsius)))
kI12f = 3*(1/f)*a*exp(za*v*F/(R*(273.16+celsius)))
kI12b = 2*f*b*exp(zb*v*F/(R*(273.16+celsius)))
kI23f = 2*(1/f)*a*exp(za*v*F/(R*(273.16+celsius)))
kI23b = 3*f*b*exp(zb*v*F/(R*(273.16+celsius)))
kI34f = (1/f)*a*exp(za*v*F/(R*(273.16+celsius)))
kI34b = 4*f*b*exp(zb*v*F/(R*(273.16+celsius)))
kI45f = q*c*exp(zc*v*F/(R*(273.16+celsius)))
kI45b = (1/q)*d*exp(zd*v*F/(R*(273.16+celsius)))
}
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