: Rod Photoreceptor Ca and Calcium channel : Ref. Kourenny and Liu 2002 ABME 30 : 1196-1203 : Modification 2004-02-07 NEURON { SUFFIX Ca USEION Ca WRITE iCa VALENCE 2 RANGE gCabar,VhalfCam,SCam RANGE VhalfCah,SCah RANGE eCa,aomCa,bomCa RANGE gammaohCa,deltaohCa } UNITS { (mA) = (milliamp) (mV) = (millivolt) (mS) = (millimho) (mol)= (1) (M) = (mol/liter) (uM) = (micro M) } PARAMETER { : Calcium channel gCabar = 4 (mS/cm2) <0,1e9> :different from ABME paper eCa = 40 (mV) aomCa = 100 (/s) : changed from 3.10/s, 20/s bomCa = 100 (/s) gammaohCa = 10 (/s) deltaohCa =10 (/s) VhalfCam=-10.0 (mV) VhalfCah=11 (mV) SCam =6.0 (mV) SCah =9 (mV) } STATE { mCa hCa } ASSIGNED { gCa (mho/cm2) v (mV) iCa (mA/cm2) infmCa taumCa (ms) infhCa tauhCa (ms) } INITIAL { rate(v) mCa = infmCa hCa = infhCa } BREAKPOINT { SOLVE states METHOD cnexp gCa = (0.001)*gCabar*mCa*hCa : g is in unit of S/cm2 ,i is in unit of mA/cm2 and v is in mV iCa = gCa*(v - eCa) : the current is in the unit of mA/cm2 } DERIVATIVE states { rate(v) mCa' = (infmCa - mCa)/taumCa hCa'= (infhCa-hCa)/tauhCa } FUNCTION alphamCa(v(mV))(/ms) { alphamCa = 0.001*aomCa*exp( (v - VhalfCam)/(2*SCam) ) } FUNCTION betamCa(v(mV))(/ms) { betamCa = 0.001*bomCa*exp( - ( v-VhalfCam)/(2*SCam) ) } FUNCTION gammahCa(v(mV))(/ms) { gammahCa = 0.001*gammaohCa*exp( (v - VhalfCah)/(2*SCah)) } FUNCTION deltahCa(v(mV))(/ms) { deltahCa = 0.001*deltaohCa*exp( - ( v-VhalfCah)/(2*SCah) ) } PROCEDURE rate(v (mV)) { LOCAL a, b,c, d a = alphamCa(v) b = betamCa(v) taumCa = 1/(a + b) infmCa = a/(a + b) c = gammahCa(v) d = deltahCa(v) tauhCa = 1/(c + d) infhCa = d/(c + d) }