SEROTONIN POTENTIATES DOPAMINE INHIBITION OF VENTRAL TEGMENTAL AREA NEURONS
Brodie, Mark S., E. Bradshaw Bunney.
Department of Physiology and Biophysics, University of Illinois at Chicago,
College of Medicine, Chicago, IL 60612 U.S.A. and Department of Emergency
Medicine, University of Illinois at Chicago, College of Medicine, Chicago, IL
APStracts 3:0117N, 1996.
SUMMARY AND CONCLUSIONS
1. The ventral tegmental area (VTA) has been implicated in both the rewarding
effects of drugs of abuse and the etiology of schizophrenia. We report here
that serotonin potentiates the inhibitory effect of dopamine on dopaminergic
VTA neurons. Dopamine (0.5 - 10 [mu]M) inhibited the spontaneous firing of
putative dopamine-containing neurons of the VTA. Serotonin (5 - 10 [mu]M)
itself did not significantly alter the spontaneous firing rate; however, in
the presence of serotonin, the inhibitory potency of dopamine was
significantly increased. 2. The inhibitory potency of the dopamine agonist
quinpirole was also increased by serotonin. 3. Serotonin-induced potentiation
was also produced by the selective 5-HT 2 agonist, DOI ((+/-)-2,5-dimethoxy-4-
iodoamphetamine), and was reversed by the selective 5-HT 2 antagonist
ketanserin. 4. This novel action of serotonin on dopaminergic neurons has
important implications for the development of drugs to treat schizophrenia,
and for the identification of agents which will be useful in treating drug
abuse disorders like alcoholism.
Received 18 April 1996; accepted in final form 5 June 1996.
APS Manuscript Number J325-6.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96