TITLE potassium Kv3.1 membrane channel for STh COMMENT Potassium Kv3.1 membrane channel for STh. Based on derived kinetics from Wigmore & Lacey 2000. Their primary experiments were performed at 32degC How the q10 works: There is a q10 for the rates (alpha and beta's) called Q10 and a Q10 for the maximum conductance called gmaxQ10. The q10s should have been measured at specific temperatures temp1 and temp2 (that are 10degC apart). Ideally, as Q10 is temperature dependant, we should know these two temperatures. We used to follow the more formal Arrhenius derived Q10 approach. The temperature at which this channel's kinetics were recorded is tempb (base temperature). What we then need to calculate is the desired rate scale for now working at temperature celsius (rate_k). This was given by the empirical Arrhenius equation, using the Q10, but now is using the quick Q10 approximation. ENDCOMMENT UNITS { (mV) = (millivolt) (mA) = (milliamp) } INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} NEURON { SUFFIX Kv31 USEION k READ ki,ek WRITE ik RANGE gk GLOBAL activate_Q10,Q10,gmaxQ10,rate_k,gmax_k,temp1,temp2,tempb } PARAMETER { v (mV) dt (ms) gk = 0.015 (mho/cm2) ek ki celsius activate_Q10 = 1 Q10 = 1.700025939e+00 gmaxQ10 = 1.700025939e+00 temp1 = 20.0 (degC) temp2 = 30.0 (degC) tempb = 32.0 (degC) } STATE { p } ASSIGNED { ik (mA/cm2) pinf ptau (ms) rate_k gmax_k } BREAKPOINT { SOLVE states METHOD cnexp ik = (gk*gmax_k)*p*(v-ek) } UNITSOFF INITIAL { LOCAL ktemp,ktempb,ktemp1,ktemp2 if (activate_Q10>0) { rate_k = Q10^((celsius-tempb)/10) gmax_k = gmaxQ10^((celsius-tempb)/10) }else{ rate_k = 1.0 gmax_k = 1.0 } settables(v) p = pinf } DERIVATIVE states { settables(v) p' = (pinf-p)/ptau } PROCEDURE settables(v) {:Computes rate and other constants at current v. :Call once from HOC to initialize inf at resting v. :Voltage shift (for temp effects) of -5.08 TABLE pinf, ptau DEPEND celsius FROM -100 TO 100 WITH 400 pinf = 1.0/(1.0+exp((v + -0.083699749)/ -9.0)) ptau = ((7.3/(exp((v + 32.9163003)/-14.0)+exp((v + 2.91630025)/16.0)))+1) / rate_k } UNITSON