Serotonin 5-HT2 receptor stimulation of dopamine release in the posterior but not anterior nucleus accumbens of the rat

The objective of the present study was to examine the involvement of seroto nin 5-HT2 receptors within the rat nucleus accumbens (Acc) in the regulatio n of dopamine (DA) release using in vivo microdialysis, Perfusion with the 5-HT2 agonist (+)-1 -(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), at concentrations of 25-250 mu M, through microdialysis probes located in the posterior Acc increased extracellular DA levels to a maximum of 200% of bas eline. DOI-induced increases in the extracellular levels of DA were Ca2+ de pendent and were inhibited by co-perfusion with the 5-HT2 antagonist LY-53, 857, DOI enhancement of the extracellular concentrations of DA was observed when probes were implanted in the Acc core and shell regions posterior to anteroposterior +1.2 mm from bregma, whereas a small reduction in the extra cellular levels of DA was observed in the anterior Acc. There were no diffe rences between core and shell subdivisions within either the anterior or th e posterior Ace. These results suggest that activation of 5-HT2 receptors w ithin the posterior, but not anterior, Ace stimulates DA release, indicatin g rostral-caudal differences in the interactions of 5-HT with DA systems in the Acc.