TITLE T-calcium channel : gate h, taus Kloeckner 99 and Chemin 2002; : gate m: Lee, Dand 99 : q10s Coulter 89 UNITS { (mA) = (milliamp) (mV) = (millivolt) : hier eigene Befehle (molar) = (1/liter) (mM) = (millimolar) FARADAY = 96520 (coul) R = 8.3134 (joule/degC) KTOMV = .0853 (mV/degC) F = 96485 (coul) } PARAMETER { v (mV) celsius = 6.3 (degC) PcaTbar = .000011 (cm/s) cai (mM) cao (mM) q10Ampl=3.3 q10m=3.55 q10h=2.8 } NEURON { SUFFIX cat USEION ca READ cai,cao WRITE ica RANGE PcaTbar,cai } STATE { m h } ASSIGNED { ica (mA/cm2) PcaT (cm/s) } INITIAL { m = minf(v) h = hinf(v) } UNITSOFF BREAKPOINT { SOLVE states METHOD cnexp PcaT = PcaTbar*m*m*h ica = PcaT*ghk(v,cai,cao) } DERIVATIVE states { : exact when v held constant m' = (minf(v) - m)/m_tau(v) h' = (hinf(v) - h)/h_tau(v) } FUNCTION ghk(v(mV), ci(mM), co(mM)) (mV) { LOCAL a, qtAmpl qtAmpl=q10Ampl^((celsius-23)/10) a=2*F*v/(R*(celsius+273.15)*1000) ghk=qtAmpl*2*F/1000*(co - ci*exp(a))*func(a) } FUNCTION func(a) { if (fabs(a) < 1e-4) { func = -1 + a/2 }else{ func = a/(1-exp(a)) } } FUNCTION hinf(v(mV)) { TABLE FROM -150 TO 150 WITH 3000 :Mitti hinf = 1/(1+exp((v+72)/3.7)) } FUNCTION minf(v(mV)) { TABLE FROM -150 TO 150 WITH 3000 :Mitti minf = (1/(1+exp(-(v+31.4)/8.8)))^0.5 } FUNCTION m_tau(v(mV)) (ms) { LOCAL f1,f2, qtm TABLE FROM -150 TO 150 WITH 3000 :Mitti qtm=q10m^((celsius-23)/10) f1=1/(1+exp(-(v-7.63)/28.47))+0.01 f2=62.82/(1+exp((v+37.02)/5.27))+3.78 m_tau=f1*f2/qtm } FUNCTION h_tau(v(mV)) (ms) { LOCAL alphah, localhinf,qth TABLE FROM -150 TO 150 WITH 3000 :Mitti qth=q10h^((celsius-23)/10) localhinf = 1/(1+exp((v+72)/3.7)) alphah=0.0021/(1+exp((v+65.77)/4.32)) h_tau = localhinf/(qth*alphah) } UNITSON