TITLE slow ATP diffusion
NEURON{
POINT_PROCESS AtP_slow
RANGE atp,h,c0cleft
RANGE tx1, k, hydrolysis}
UNITS{
(molar)=(1/liter)
(uM)=(micromolar)
(um)=(micron)
(nA)=(nanoamp)
}
CONSTANT {
PI=3.1415927
}
PARAMETER {
c0cleft = 1 (uM):initial quantity atp
h(um)
tx1(ms)
k = 10
}
ASSIGNED{
atp (uM)
hydrolysis (uM)
}
INITIAL {
:tx1=10
atp=0
}
BREAKPOINT
{
at_time(tx1)
if (t<=tx1){
atp=0
}
if(t>tx1) {
UNITSOFF
hydrolysis = 0.1*c0cleft*(1-exp(k*(tx1-t)))
atp = c0cleft*(1-exp(0.00025*(tx1-t))) - hydrolysis
if(atp>c0cleft){atp=c0cleft}
if(atp<0){atp=0}
}
}
NET_RECEIVE (weight)
{
tx1=t
}