RT Journal Article SR Electronic T1 Dopamine D3 Receptors Modulate Evoked Dopamine Release from Slices of Rat Nucleus Accumbens Via Muscarinic Receptors, But Not from the Striatum JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 994 OP 998 VO 291 IS 3 A1 Yamada, Shigeto A1 Harano, Mutsuo A1 Annoh, Naoko A1 Tanaka, Masatoshi YR 1999 UL http://jpet.aspetjournals.org/content/291/3/994.abstract AB It is not clear whether dopamine D3 receptor contributes to the regional difference in dopamine antagonist-induced increase in the evoked dopamine release from the nucleus accumbens and striatum. We investigated the regional differences in augmentation of electrically evoked dopamine release induced by preferential dopamine D2 or D3 receptor antagonists from slices of the rat striatum and nucleus accumbens. Haloperidol, a preferential dopamine D2 receptor antagonist, enhanced the evoked dopamine release from both the striatum and nucleus accumbens. Preferential dopamine D3 antagonists,cis-(+)-(1S,2R)-5-methoxy-1-methyl-2-(di-n-propylamino)tetralin HCl [(+)-UH232] and 5,6-dimethoxy-2-(di-n-propylamine)indan (U-99194A) resulted in a greater increase in the evoked dopamine released from the nucleus accumbens compared with that from the striatum. Moreover, U-99194A attenuated the quinpirole-induced reduction of evoked dopamine release from the nucleus accumbens but not from the striatum. When slices were superfused with pirenzepine, a muscarinic receptor antagonist, the increase in the evoked dopamine release by (+)-UH232 or U-99194A was reduced in the nucleus accumbens to the same level as that in the striatum. Our results indicate that the preferential D3 receptor antagonists-induced increase in evoked dopamine release is probably mediated by the cholinergic system in the nucleus accumbens, which contains more postsynaptic dopamine D3receptors than the striatum. The American Society for Pharmacology and Experimental Therapeutics