I'm really interested on which brain receptors MPA works on.
I still wonder if it works on seretonin at all - personally i never felt any seretonin action at all...
To the best of my knowledge, all of the major monoamine neurotransmitters (so, notably, serotonin, dopamine, noradrenaline etc.) are affected to some extent. Seems fairly likely that it's a releasing agent of dopamine and noradrenaline and that it's also a MAOI and competitive MA transporter antagonist (based on a combination of anecdotal and experimental evidence and speculation that I've come across). Although the serotonin element is almost invisible, it's probably there somewhere even if only as a byproduct of its role as a MAOI. Overall, the effects are very probably an increase in levels of several neurotransmitters with dopamine and/or noradrenaline being hit substantially more than the other monoamines.
It doesn't make for great reading tbh. I really need to quit using this stuff.