Different nicotinic acetylcholine receptor subtypes mediating striatal and prefrontal cortical [H-3]dopamine release

Different nicotinic acetylcholine receptor subtypes appear to modulate dopamine release from the striatum and prefrontal cortex. In this study a combination Of subtype-selective antagonists and agonists were used to extensively characterize the nAChRs involved in dopamine release from slice preparations of these two brain regions. alpha-conotoxin-MII inhibited nicotine-evoked [H-3]dopamine (DA) release from striatum by 45% but did not affect cortical dopamine release. Neither methyllycaconitine, alpha-bungarotoxin, nor alpha-conotoxin-Iml affected nicotine-evoked [H-3]DA release from either striatum or prefrontal cortex. MG 624 a novel selective nAChR antagonist. inhibited cortical [H-3]DA by 53% but had no effect on striatal release. Compared to nicotine, (+/-)-UB-165 showed less efficacy with respect to dopamine release from striatum, and had no effect on cortical dopamine release. (+/-)-UB-165-evoked striatal dopamine release was completely blocked by mecamylamine, partially blocked (up to 55%) by alpha-conotoxin-Iml and unaffected by methyllycaconitine or alpha-conotoxin-Iml. alpha4beta2* and alpha6beta2beta3* nAChRs appear to play a role in striatal dopamine release, whereas alpha4beta2* nAChRs modulate release from prefrontal cortex. alpha7* nAChRs do not appear to play a role in nAChR-mediated dopamine release front either brain re.-ion. (C) 2004 Elsevier Ltd. All rights reserved.