TITLE Calcium dynamics for N, P/Q, R calcium pool
NEURON {
SUFFIX cadyn
USEION ca READ ica, cai WRITE cai VALENCE 2
RANGE pump, cainf, taur, drive
}
UNITS {
(molar) = (1/liter)
(mM) = (millimolar)
(um) = (micron)
(mA) = (milliamp)
(msM) = (ms mM)
FARADAY = (faraday) (coulomb)
}
PARAMETER {
drive = 10000 (1)
depth = 0.1 (um)
cainf = 10e-6 (mM)
taur = 43 (ms)
kt = 1e-4 (mM/ms)
kd = 1e-4 (mM)
pump = 0.02
}
STATE { cai (mM) }
INITIAL { cai = cainf }
ASSIGNED {
ica (mA/cm2)
drive_channel (mM/ms)
drive_pump (mM/ms)
}
BREAKPOINT {
SOLVE state METHOD cnexp
}
DERIVATIVE state {
drive_channel = -drive*ica/(2*FARADAY*depth)
if (drive_channel <= 0.) { drive_channel = 0. }
drive_pump = -kt*cai/(cai+kd)
cai' = (drive_channel+pump*drive_pump+(cainf-cai)/taur)
}
COMMENT
ENDCOMMENT