TITLE LCa calcium channel with fixed reversal potential : LCa channel with parameters from US Bhalla and JM Bower, : J. Neurophysiol. 69:1948-1983 (1993) : Andrew Davison, The Babraham Institute, 1998. NEURON { SUFFIX lcafixed USEION ca WRITE ica RANGE gcabar, ica GLOBAL sinf, rinf, stau, rtau } UNITS { (mA) = (milliamp) (mV) = (millivolt) (molar) = (1/liter) (mM) = (millimolar) } INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} CONSTANT { eca = 70 (mV) } PARAMETER { v (mV) dt (ms) gcabar = 0.120 (mho/cm2) <0,1e9> : eca = 70 (mV) } STATE { r s } ASSIGNED { ica (mA/cm2) sinf rinf stau (ms) rtau (ms) } INITIAL { rates(v) s = sinf r = rinf } BREAKPOINT { SOLVE states METHOD cnexp ica = gcabar*s*r*(v - eca) } DERIVATIVE states { rates(v) s' = (sinf - s)/stau r' = (rinf - r)/rtau } FUNCTION alp(v(mV),i) (/ms) { if (i==0) { alp = 7.5(/ms)/(1 + exp((-v *1(/mV) + 13)/7)) }else if (i==1){ alp = 0.0068(/ms)/(1 + exp((v *1(/mV) + 30)/12)) } } FUNCTION bet(v(mV),i)(/ms) { if (i==0) { bet = 1.65(/ms)/(1 + exp((v *1(/mV) - 14)/4)) }else if (i==1){ bet = 0.06(/ms)/(1 + exp(-v* 1(/mV)/11)) } } PROCEDURE rates(v(mV)) {LOCAL a, b TABLE sinf, rinf, stau, rtau FROM -100 TO 100 WITH 200 a = alp(v,0) b=bet(v,0) stau = 1/(a + b) sinf = a/(a + b) a = alp(v,1) b=bet(v,1) rtau = 1/(a + b) rinf = a/(a + b) }