: HH TEA-sensitive Purkinje potassium current : Created 8/5/02 - nwg : Suffix from kpkj to Kv3_4 NEURON { SUFFIX Kv3_4 USEION k READ ek WRITE ik RANGE gkbar, ik RANGE minf, hinf, mtau, htau } UNITS { (mV) = (millivolt) (mA) = (milliamp) } CONSTANT { q10 = 3 } PARAMETER { v (mV) gkbar = .004 (mho/cm2) mivh = -24 (mV) mik = 15.4 (1) mty0 = .00012851 mtvh1 = 100.7 (mV) mtk1 = 12.9 (1) mtvh2 = -56.0 (mV) mtk2 = -23.1 (1) hiy0 = .31 hiA = .69 hivh = -5.802 (mV) hik = 11.2 (1) ek } ASSIGNED { ik (mA/cm2) minf mtau (ms) hinf htau (ms) qt } STATE { m h } INITIAL { rates(v) m = minf h = hinf qt = q10^((celsius-37 (degC))/10 (degC)) } BREAKPOINT { SOLVE states METHOD cnexp ik = gkbar * m^3 * h * (v - ek) } DERIVATIVE states { rates(v) m' = (minf - m) / mtau h' = (hinf - h) / htau } PROCEDURE rates( Vm (mV)) { LOCAL v v = Vm + 11 : Account for Junction Potential minf = 1/(1+exp(-(v-mivh)/mik)) mtau = (1000) * mtau_func(v) /qt hinf = hiy0 + hiA/(1+exp((v-hivh)/hik)) htau = 1000 * htau_func(v) / qt } FUNCTION mtau_func (v (mV)) (ms) { if (v < -35) { mtau_func = (3.4225e-5+.00498*exp(-v/-28.29))*3 } else { mtau_func = (mty0 + 1/(exp((v+mtvh1)/mtk1)+exp((v+mtvh2)/mtk2))) } } FUNCTION htau_func(Vm (mV)) (ms) { if ( Vm > 0) { htau_func = .0012+.0023*exp(-.141*Vm) } else { htau_func = 1.2202e-05 + .012 * exp(-((Vm-(-56.3))/49.6)^2) } }