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138 lines
2.8 KiB
138 lines
2.8 KiB
2 years ago
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TITLE pyrna.mod DCN pyramidal cell model sodium channel
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COMMENT
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Revised version of DCN Pyramidal cell model sodium channel
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This model implements part of a Dorsal Cochlear Nucleus Pyramidal point cell
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based on kinetic data from Kanold and Manis (1999) and Kanold's dissertation (1999)
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-- 15 Jan 1999 P. Manis
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This mechanism is the fast sodium channel portion of the model.
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Orignal: 2/10/02. P. Manis.
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Extraced from Pyr.mod, 7/24/2014.
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ENDCOMMENT
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UNITS {
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(mA) = (milliamp)
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(mV) = (millivolt)
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}
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NEURON {
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THREADSAFE
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SUFFIX napyr
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USEION na READ ena WRITE ina
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RANGE gna, minf, hinf, ninf, gbar : sodium channels and delayed rectifier
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RANGE mtau, htau, ntau : time constants for sodium channels and delayed rectifier
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}
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INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
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PARAMETER {
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v (mV)
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celsius (degC)
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dt (ms)
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ek (mV) : = -81.5 (mV)
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ena (mV) : = 50.0 (mV)
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gbar = 0.02857 (mho/cm2) <0,1e9>
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mtau0 = 0.05 (ms) <0.01,100>
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htau0 = 0.5 (ms) <0.1,100>
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ntau = 0.5 (ms) <0.1,100>
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}
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STATE {
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m h
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}
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ASSIGNED {
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gna (mho/cm2)
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ina (mA/cm2)
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minf hinf mtau htau
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}
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LOCAL mexp, hexp
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BREAKPOINT {
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SOLVE states METHOD cnexp
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gna = gbar*m*m*h
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ina = gna*(v - ena)
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}
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UNITSOFF
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INITIAL {
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rates(v)
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m = minf
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h = hinf
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}
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DERIVATIVE states {
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rates(v)
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m' = (minf - m) / mtau
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h' = (hinf - h) / htau
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}
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LOCAL q10
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PROCEDURE rates(v(mV)) { :Computes rate and other constants at current v.
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:Call once from HOC to initialize inf at resting v.
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LOCAL alpha, beta, sum
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TABLE minf, mtau, hinf, htau DEPEND celsius FROM -200 TO 100 WITH 400
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UNITSOFF
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q10 = 3^((celsius - 22)/10)
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: "m" sodium activation system
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minf = na_m(v)
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mtau = na_mt(v)
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: "h" sodium inactivation system
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hinf = na_h(v)
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htau = na_ht(v)
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}
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: Make these as functions so we can view them from hoc, although this
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: may slow things down a bit
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FUNCTION na_m(x) { : sodium activation
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na_m = 1/(1+exp(-(x+38)/3.0)) : POK version
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: na_m = alphbet(x,35,0,5,-10) :de Schutter (doesn't work well in our version)
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: na_m = na_m/(na_m + alphbet(x,7,0,65,20))
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}
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FUNCTION na_mt(x) { : sodium activation with taus
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na_mt = mtau0 : flat time constants
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: na_mt = alphbet(x,35,0,5,-10)
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: na_mt = 1/(na_mt + alphbet(x,7,0,65,20))
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}
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FUNCTION na_h(x) { : sodium inactivation
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na_h = 1/(1+exp((x+43)/3.0)) : flat time constants (POK version)
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: na_h = alphbet(x,0.225,1,80,10)
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: na_h = na_h/(na_h + alphbet(x,7.5,0,-3,-18))
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}
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FUNCTION na_ht(x) { : sodium inactivation tau
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na_ht = htau0 : POK: flat time constants
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: na_ht = alphbet(x,0.225,1,80,10) : de Schutter version (doesn't work well with other stuff)
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: na_ht = 1/(na_ht + alphbet(x,7.5,0,-3,-18))
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}
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FUNCTION alphbet(x,A,B,C,D) { : alpha/beta general functions for
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: transcrbing GENESIS models
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alphbet = A/(B+exp((x+C)/D))
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}
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UNITSON
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