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131 lines
2.5 KiB
131 lines
2.5 KiB
2 years ago
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TITLE nap.mod Persistent sodium conductance
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COMMENT
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Persistent sodium current from deSchutter and Bower, J. Neurophys.
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71:375, 1994.
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2/10/02, 10/10/2014. P. Manis.
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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 nap
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USEION na READ ena WRITE ina
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RANGE nap_inf, nap_tau, napi_inf, napi_tau
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RANGE gbar, gnap
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RANGE nap_A, nap_B, nap_C, nap_D, nap_E, nap_F, nap_G, nap_H
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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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ena (mV) : = 50.0 (mV)
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gbar = 0.00001 (mho/cm2) <0,1e9>
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q10tau = 3.0
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q10g = 2.0
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nap_shift = 0 (mV)
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nap_A = 200 (/ms): parameters from Bowers et al.
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nap_B = 1
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nap_C = -18 (mV)
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nap_D = -16 (mV)
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nap_E = 25 (/ms)
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nap_F = 1
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nap_G = 58 (mV)
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nap_H = 8 (mV)
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}
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STATE {
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nap napi
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}
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ASSIGNED {
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gnap (mho/cm2)
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ina (mA/cm2)
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nap_inf
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nap_tau (ms)
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nap_tau1 (/ms)
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nap_tau2 (/ms)
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napi_inf
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napi_tau (ms)
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napi_tau1 (/ms)
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napi_tau2 (/ms)
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qg () : computed q10 for gnabar based on q10g
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q10 ()
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}
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BREAKPOINT {
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SOLVE states METHOD cnexp
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gnap = gbar*nap*nap*nap*napi
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ina = gnap*(v-ena)
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}
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INITIAL {
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qg = q10g^((celsius-22)/10 (degC))
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q10 = q10tau^((celsius - 22)/10 (degC)) : if you don't like room temp, it can be changed!
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rates(v)
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nap = nap_inf
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napi = napi_inf
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}
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DERIVATIVE states {
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rates(v)
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nap' = (nap_inf - nap) / nap_tau
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napi' = (napi_inf - napi) / napi_tau
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}
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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 x
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: "nap" persistent sodium system
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nap_inf = na_p(v + nap_shift)
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nap_tau1 = nap_A/(nap_B + exp((v + nap_shift + nap_C)/nap_D))
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nap_tau2 = nap_E/(nap_F + exp((v + nap_shift + nap_G)/nap_H))
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nap_tau = 1./(nap_tau1 + nap_tau2)
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:nap_tau = na_ptau(v + nap_shift)
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: "nap" persistent sodium system - inactivation...
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napi_inf = na_pi(v + nap_shift)
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napi_tau1 = (1 (/ms)) /(0.06435/(1+exp((v + nap_shift + 73.26415)/3.71928 (mV))))
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napi_tau2 = (0.13496 (/ms))/(1 +exp((v + nap_shift + 10.27853)/(-9.09334 (mV))))
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napi_tau = 1 /(napi_tau1 + napi_tau2)
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}
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LOCAL p
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FUNCTION na_p(v (mV)) { : persistent sodium activation
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: Bowers
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p = nap_A/(nap_B + exp((v + nap_shift + nap_C)/nap_D))
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na_p = p/(p+nap_E/(nap_F + exp((v + nap_shift + nap_G)/nap_H)))
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}
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FUNCTION na_pi(x (mV)) { : persistent sodium inactivation
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: Bowers
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na_pi = 0.06435/(1+exp((x+73.26415)/3.71928 (mV)))
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na_pi = na_pi/(na_pi + (0.13496/(1+exp((v+10.27853)/(-9.09334 (mV))))))
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}
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