Hey inflo did u get pm?
Guys I confess o haven't read the last few posts but it seems to me that sammy is right on the money. Dopamine and serotonin arent even the same class of transmitter substance. While chemically they are kissing cousins, the brain uses them in vary different ways. Serotonin is a neuromodulator while dopamine is a neuro transmitter. The difference is that serotonin is more like a hormone. Evolutionary it came first, therefore, all our serotonin is released from the back of rhe brain(cerebullum, pons l etc ). From these areas serotonin is released regularly where it spreads out through the entire brain.
The vital part of the discussion is that serotonin effects how dopamine works, though not vice versa. Dopamine acts by hopping miniscule distances between cells - it's basically how the brain gets shit done when time is of the essence. Meanwhile, whenever dopamine is released across a synapse, the receiving cell will also have a few serotonin molecules already attached to it. Serotonins job is to mitigate the effects of the dopamine. Its kind of like a smoother and more consistent version of GABA. For anyone interested, this whole process I have outlined is called "neural integration".
Quickly, shambles point about serotonin system is an interesting one. I hope someone else can add to this but s good starting point is that a neurochemical would, on its own, be completely useless. It would be like mailing a letter to someone at random instead of someone specific. No, brain chemicals also need addresses. That's what a receptor is for, and as a result the brain has shit loads of different ones. Back in 2000 they had found 16 separate serotonin receptors.
I'm about to pass out - sorry I went on and couldn't wrap up properly.