TITLE Small conductance calcium dependent potassium current (SK) of deep cerebellar nucleus (DCN) neuron
COMMENT
This channel's conductance is affected by the calcium concentration which
has been accumulated through the CaHVA channel and kept track of by CaConc.mod.
Calcium entry through the CaLVA channel is kept track of by CalConc.mod
and doesn't affect the SK channel.
Translated from GENESIS by Johannes Luthman and Volker Steuber.
ENDCOMMENT
NEURON {
SUFFIX dcnSK
USEION ca READ cai VALENCE 2
USEION k READ ek WRITE ik
RANGE gbar, z, ik
GLOBAL qdeltat
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
(molar) = (1/liter)
(mM) = (millimolar)
}
PARAMETER {
qdeltat = 1
gbar = 1e-5 (siemens/cm2)
}
ASSIGNED {
v (mV)
ek (mV)
ik (mA/cm2)
cai (mM)
zinf
tauz (ms)
}
STATE {
z : calcium-dependent activation variable
}
INITIAL {
rate(cai)
z = zinf
}
BREAKPOINT {
SOLVE states METHOD cnexp
ik = gbar * z * (v - ek)
}
DERIVATIVE states {
rate(cai)
z' = (zinf - z) / tauz
}
PROCEDURE rate(cai(mM)) {
TABLE zinf, tauz FROM 0 TO 0.01 WITH 300
zinf = cai*cai*cai*cai / (cai*cai*cai*cai + 8.1e-15) : 8.1e-15 is the result of (3e-4)^4
if (cai < 0.005) {
tauz = 1 - (186.67 * cai)
} else {
tauz = 0.0667
}
tauz = tauz / qdeltat
}