TITLE Cerebellum Granule Cell Model
COMMENT
CaHVA channel
Author: E.D'Angelo, T.Nieus, A. Fontana
Last revised: 8.5.2000
ENDCOMMENT
NEURON {
SUFFIX GRC_CA
USEION ca READ eca WRITE ica
RANGE gcabar, ica, g, alpha_s, beta_s, alpha_u, beta_u
RANGE Aalpha_s, Kalpha_s, V0alpha_s
RANGE Abeta_s, Kbeta_s, V0beta_s
RANGE Aalpha_u, Kalpha_u, V0alpha_u
RANGE Abeta_u, Kbeta_u, V0beta_u
RANGE s_inf, tau_s, u_inf, tau_u
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
}
PARAMETER {
:Kalpha_s = 0.063 (/mV) Checked!
:Kbeta_s = -0.039 (/mV) Checked!
:Kalpha_u = -0.055 (/mV) Checked!
:Kbeta_u = 0.012 (/mV) Checked!
Aalpha_s = 0.04944 (/ms)
Kalpha_s = 15.87301587302 (mV)
V0alpha_s = -29.06 (mV)
Abeta_s = 0.08298 (/ms)
Kbeta_s = -25.641 (mV)
V0beta_s = -18.66 (mV)
Aalpha_u = 0.0013 (/ms)
Kalpha_u = -18.183 (mV)
V0alpha_u = -48 (mV)
Abeta_u = 0.0013 (/ms)
Kbeta_u = 83.33 (mV)
V0beta_u = -48 (mV)
v (mV)
gcabar= 0.00046 (mho/cm2)
eca = 129.33 (mV)
celsius = 30 (degC)
}
STATE {
s
u
}
ASSIGNED {
ica (mA/cm2)
s_inf
u_inf
tau_s (ms)
tau_u (ms)
g (mho/cm2)
alpha_s (/ms)
beta_s (/ms)
alpha_u (/ms)
beta_u (/ms)
}
INITIAL {
rate(v)
s = s_inf
u = u_inf
}
BREAKPOINT {
SOLVE states METHOD derivimplicit
g = gcabar*s*s*u
ica = g*(v - eca)
alpha_s = alp_s(v)
beta_s = bet_s(v)
alpha_u = alp_u(v)
beta_u = bet_u(v)
}
DERIVATIVE states {
rate(v)
s' =(s_inf - s)/tau_s
u' =(u_inf - u)/tau_u
}
FUNCTION alp_s(v(mV))(/ms) { LOCAL Q10
Q10 = 3^((celsius-20(degC))/10(degC))
alp_s = Q10*Aalpha_s*exp((v-V0alpha_s)/Kalpha_s)
}
FUNCTION bet_s(v(mV))(/ms) { LOCAL Q10
Q10 = 3^((celsius-20(degC))/10(degC))
bet_s = Q10*Abeta_s*exp((v-V0beta_s)/Kbeta_s)
}
FUNCTION alp_u(v(mV))(/ms) { LOCAL Q10
Q10 = 3^((celsius-20(degC))/10(degC))
alp_u = Q10*Aalpha_u*exp((v-V0alpha_u)/Kalpha_u)
}
FUNCTION bet_u(v(mV))(/ms) { LOCAL Q10
Q10 = 3^((celsius-20(degC))/10(degC))
bet_u = Q10*Abeta_u*exp((v-V0beta_u)/Kbeta_u)
}
PROCEDURE rate(v (mV)) {LOCAL a_s, b_s, a_u, b_u
TABLE s_inf, tau_s, u_inf, tau_u
DEPEND Aalpha_s, Kalpha_s, V0alpha_s,
Abeta_s, Kbeta_s, V0beta_s,
Aalpha_u, Kalpha_u, V0alpha_u,
Abeta_u, Kbeta_u, V0beta_u, celsius FROM -100 TO 30 WITH 13000
a_s = alp_s(v)
b_s = bet_s(v)
a_u = alp_u(v)
b_u = bet_u(v)
s_inf = a_s/(a_s + b_s)
tau_s = 1/(a_s + b_s)
u_inf = a_u/(a_u + b_u)
tau_u = 1/(a_u + b_u)
}