I think I´ve got a fairly detailed description of the problem in my head now (although being detailed doesn´t necessarily mean that it´s right). I will try to write it up so that it makes sense sometime later in the week, and then we can compare notes.
Trouble is, (to quote Homer Simpson) I´m a lazy, lazy man, and I only feel like writing it up because I´m worried that someone (like you!) will ´scoop´ me.
Haha, it sounds like I´m going to rip you off now.
I should never have read your theory!
I think large increases in extracellular ATP may be linked to Naviaux's Cell Danger Response. To be honest though that's about as far as my knowledge goes, i'm sure someone with more knowledge on the subject will put me right!