#these are the initial values for the variables
c1(0)=1
o1(0)=0
o1p(0)=0.8
#note: o1p(0)=1/(1+(k1m/k1p))
#these are the values of the parameters
param kap=0.5, kam=0.1, kbp=0.10, kbm=0.05, cad=0.2
param V=20, Vca=60,g=10
#these are the rate functions
c2=1-o1-c1
va(c1,o1)=kap*c1-kam*o1
vb(o1,c2)=kbp*cad*o1-kbm*c2
#these are the complete equations
dc1/dt=-va(c1,o1)
do1/dt=va(c1,o1)-vb(o1,c2)
#rapid equilibrium approximation (va(c1,o1) = 0) gives
do1p/dt=-kbp*cad*o1p+kbm*(1-(1+(kam/kap))*o1p)
#the currents
aux i=g*o1*(V-Vca)
aux ip=g*o1p*(V-Vca)
done