TITLE T-type calcium current (Cav3.3) UNITS { (mV) = (millivolt) (mA) = (milliamp) (S) = (siemens) (molar) = (1/liter) (mM) = (millimolar) FARADAY = (faraday) (coulomb) R = (k-mole) (joule/degC) } NEURON { SUFFIX cat33 USEION cal READ cali, calo WRITE ical VALENCE 2 RANGE pbar, ical } PARAMETER { pbar = 0.0 (cm/s) :q = 1 : room temperature 21 C q = 3 : body temperature 35 C } ASSIGNED { v (mV) ical (mA/cm2) ecal (mV) celsius (degC) cali (mM) calo (mM) minf mtau (ms) hinf htau (ms) } STATE { m h } BREAKPOINT { SOLVE states METHOD cnexp ical = pbar*m*m*m*h*ghk(v, cali, calo) } INITIAL { rates() m = minf h = hinf } DERIVATIVE states { rates() m' = (minf-m)/mtau*q h' = (hinf-h)/htau*q } PROCEDURE rates() { UNITSOFF minf = 1/(1+exp((v-(-81))/(-5.8))) mtau = (2.3+20/(1+exp((v-(-60))/9)))*3 hinf = 1/(1+exp((v-(-78.3))/6.5)) htau = 125+140/(1+exp((v-(-60))/3)) UNITSON } FUNCTION ghk(v (mV), ci (mM), co (mM)) (.001 coul/cm3) { LOCAL z, eci, eco z = (1e-3)*2*FARADAY*v/(R*(celsius+273.15)) if(z == 0) { z = z+1e-6 } eco = co*(z)/(exp(z)-1) eci = ci*(-z)/(exp(-z)-1) ghk = (1e-3)*2*FARADAY*(eci-eco) } COMMENT Rat Cav3.2 channels were isolated and transfection of human embryonic kidney cells was performed [1]. Electrophysiological recordings were done in 21 C. NEURON model by Alexander Kozlov . Kinetics of m3h type was used [2-4]. Activation time constant was scaled up accordingly. [1] Iftinca M, McKay BE, Snutch TP, McRory JE, Turner RW, Zamponi GW (2006) Temperature dependence of T-type calcium channel gating. Neuroscience 142(4):1031-42. [2] Crunelli V, Toth TI, Cope DW, Blethyn K, Hughes SW (2005) The 'window' T-type calcium current in brain dynamics of different behavioural states. J Physiol 562(Pt 1):121-9. [3] Wolf JA, Moyer JT, Lazarewicz MT, Contreras D, Benoit-Marand M, O'Donnell P, Finkel LH (2005) NMDA/AMPA ratio impacts state transitions and entrainment to oscillations in a computational model of the nucleus accumbens medium spiny projection neuron. J Neurosci 25(40):9080-95. [4] Evans RC, Maniar YM, Blackwell KT (2013) Dynamic modulation of spike timing-dependent calcium influx during corticostriatal upstates. J Neurophysiol 110(7):1631-45. ENDCOMMENT