# Morris-Lecar-like beta-cell

init v=-65.0, n=0.00016, c=0.2

# equations
dv/dt=(i+gl*(vl-v)+gk*n*(vk-v)- Ica(v) - Ikca(v,c) + gkatp*(vk-v))/cm
dn/dt=(ninf(v)-n)/tau(v)
dc/dt=f*(-alpha*ica(v) - kc*c)
# where
minf(v)=.5*(1+tanh((v-v1)/v2))
ninf(v)=.5*(1+tanh((v-v3)/v4))
tau(v)=1/(phi*cosh((v-v3)/(2*v4)))
#
# For bifurcation diagram, set auto=1 and use gkcastar as the bifurcation
# parameter:
param gkcastar=100.0, auto=0
#
param vk=-75, vl=-75, vca=25
param i=0, gk=2700, gl=150, gca=1000, cm=5300
param v1=-20.0, v2=24, v3=-16, v4=11.2, phi=0.035
param gkca=2000.0, Kca=5.0
# Ikca
ikca(v,c) = auto*gkcastar*(v-vk) + (1-auto)*gkca/(1+(Kca/c))*(v-vk)
# Calcium Handling
par alpha=4.50e-6, kc=0.15, f=0.001
# Ikatp
par gkatp=0.0
ica(v) = gca*minf(v)*(v-vca)

# track some currents
aux Condkca=gkca/(1+(Kca/c))
aux Ica=gca*minf(V)*(V-Vca)
aux Ik=gk*n*(V-Vk)
aux Curkca=Ikca(v,c)

@ meth=cvode, atol=1.0e-6, tol=1.0e-6, dt=10.0, total=40000, maxstor=10000
@ xp=t, yp=v, bound=100000000
@ xlo=0, xhi=40000, ylo=-70, yhi=-10

done