TITLE na3 : Na current for axon. No slow inact. : M.Migliore Jul. 1997 INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} NEURON { SUFFIX nax USEION na READ ena WRITE ina RANGE gbar GLOBAL minf, hinf, mtau, htau,thinf, qinf } PARAMETER { gbar = 0.010 (mho/cm2) tha = -30 (mV) : v 1/2 for act qa = 7.2 (mV) : act slope (4.5) Ra = 0.4 (/ms) : open (v) Rb = 0.124 (/ms) : close (v) thi1 = -45 (mV) : v 1/2 for inact thi2 = -45 (mV) : v 1/2 for inact qd = 1.5 (mV) : inact tau slope qg = 1.5 (mV) mmin=0.02 hmin=0.5 q10=2 Rg = 0.01 (/ms) : inact recov (v) Rd = .03 (/ms) : inact (v) thinf = -50 (mV) : inact inf slope qinf = 4 (mV) : inact inf slope ena (mV) : must be explicitly def. in hoc v (mV) dt (ms) celsius=24 (degC) } UNITS { (mA) = (milliamp) (mV) = (millivolt) (pS) = (picosiemens) (um) = (micron) } ASSIGNED { ina (mA/cm2) thegna (mho/cm2) minf hinf mtau (ms) htau (ms) } STATE { m h} INITIAL { trates(v) m=minf h=hinf thegna = gbar*m*m*m*h ina = thegna * (v - ena) } BREAKPOINT { SOLVE states thegna = gbar*m*m*m*h ina = thegna * (v - ena) } LOCAL mexp, hexp, sexp PROCEDURE states() { trates(v) m = m + mexp*(minf-m) h = h + hexp*(hinf-h) VERBATIM return 0; ENDVERBATIM } PROCEDURE trates(vm) { LOCAL a, b, qt qt=q10^((celsius-24)/10) a = trap0(vm,tha,Ra,qa) b = trap0(-vm,-tha,Rb,qa) mtau = 1/(a+b)/qt if (mtau 1e-6) { trap0 = a * (v - th) / (1 - exp(-(v - th)/q)) } else { trap0 = a * q } }