# Calcium-induced calcium release
# Goldbeter, Dupont & Berridge (1990)

XX=X*X
YY=Y*Y
VV2=v2*XX/(K22+XX)
VV3=v3*(YY/(KR2+YY))*(XX*XX/(KA4+XX*XX))
B=B0*exp(-alpha*t)

dX/dt=v0+v1*B-VV2+VV3-k4*X+k5*Y
dY/dt=VV2-VV3-k5*Y

p v0=1, v1=7.3, v2=65, v3=500, k4=10, k5=1 
p K22=1, KR2=4, KA4=.6561
p  B0=1, alpha=.25

done