Posted by Zeke on April 18, 2000, at 15:13:52
In reply to Re: Cam - serotonin and dopamine opposition, posted by Cam W. on April 17, 2000, at 21:49:55
Serotonin and dopamine opposition -- well yes and no...
The actions of neurotransmitters are complex. Saying DA and 5HT antagonize one another (or one another's actions) is best viewed as a generalization. Many subcortical circuits use serotonin at one junction and dopamine at another.
Consider also that dopamine and serotonin also act to oppose (inhibit) themselves, eg, through autoreceptors. (Or through action: ACh 'opposes' its actions in the PNS.)
Other considerations:
Be careful generalizing from results of studies in persons with abnormal brain chemistry like schizophrenia. (Does a non-schizophrenic brain act like a schizophrenic brain? In schizophrenia, some dopamine circuits are hyperactive, some hypoactive.)
Be careful generalizing transmitter function with higher level functions such as mood; Different dopamine agonists have different effects for example on mood: amphetamine tends to improve mood while levodopa tends to lower mood.
IMHO, much is to be learned from the happenings inside neurons. Along with genetics this will involve neurosteroids etc. This seems to me why antidepressants have an effective (affective) time lag whis their synaptic action is immediate.
Another complicating issue is the recent finding that transmission can occur electrically without any neurotransmitter (in certain processes).
Lastly, if one transmitter inhibits the other, we can say 'oppose' or we can say 'modulate'. I tend to see DA/5HT more in the 'modulate' sense.
poster:Zeke
thread:29285
URL: http://www.dr-bob.org/babble/20000411/msgs/30465.html