TITLE Sodium persistent current for RD Traub, J Neurophysiol 89:909-921, 2003 COMMENT Implemented by Maciej Lazarewicz 2003 (mlazarew@seas.upenn.edu) ENDCOMMENT INDEPENDENT { t FROM 0 TO 1 WITH 1 (ms) } UNITS { (mV) = (millivolt) (mA) = (milliamp) } NEURON { SUFFIX nap USEION na READ ena WRITE ina RANGE i, minf, mtau, gnap, gbar :, vhalf, k } PARAMETER { gbar = 1e-4 (mho/cm2) v ena (mV) k = 5 (mV) vhalf = -48 (mV) } ASSIGNED { ina (mA/cm2) i (mA/cm2) minf (1) mtau (ms) gnap (mho/cm2) } STATE { m } BREAKPOINT { SOLVE states METHOD cnexp gnap = gbar * m ina = gnap * ( v - ena ) i = ina } INITIAL { rate(v) m = minf } DERIVATIVE states { rate(v) m' = ( minf - m ) / mtau } UNITSOFF PROCEDURE rate(v (mV)) { if (v < -67.5 ) { minf = 0 } else{ minf = 1 / ( 1 + exp( ( vhalf - v ) / k ) ) } if( v < -40.0 ) { mtau = 100*(0.025 + 0.14 * exp( ( v + 40 ) / 10 )) }else{ mtau = 100*(0.02 + 0.145 * exp( ( - v - 40 ) / 10 )) } } UNITSON