PT - JOURNAL ARTICLE AU - Zhu Li AU - Adam J. Prus AU - Jin Dai AU - Herbert Y. Meltzer TI - Differential Effects of M<sub>1</sub> and 5-Hydroxytryptamine<sub>1A</sub> Receptors on Atypical Antipsychotic Drug-Induced Dopamine Efflux in the Medial Prefrontal Cortex AID - 10.1124/jpet.109.155663 DP - 2009 Sep 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 948--955 VI - 330 IP - 3 4099 - http://jpet.aspetjournals.org/content/330/3/948.short 4100 - http://jpet.aspetjournals.org/content/330/3/948.full SO - J Pharmacol Exp Ther2009 Sep 01; 330 AB - Systemic administration of the M1 receptor agonists N-desmethylclozapine (NDMC) and 4-[3-(4-butylpiperidin-1-yl)-propyl]-7-fluoro-4H-benzo[1,4]oxazin-3-one (AC260584) increase dopamine (DA) efflux in rat medial prefrontal cortex (mPFC). This increase is blocked by systemic administration of both telenzepine, a preferential M1 receptor antagonist, and N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide (WAY-100635), a 5-hydroxytryptamine1A receptor antagonist. The present study sought to determine whether DA efflux in the mPFC induced by the atypical antipsychotic drugs clozapine, risperidone, and olanzapine is also mediated by M1 receptor stimulation and, specifically, to determine whether these effects are mediated M1 receptors in the mPFC through use of in vivo microdialysis in awake, freely moving Sprague-Dawley rats. Telenzepine (3 mg/kg) significantly attenuated clozapine- (20 mg/kg), olanzapine- (10 mg/kg), and risperidone- (1.0 mg/kg) induced increases in mPFC DA efflux. Local mPFC perfusion of NDMC, AC260584, clozapine, risperidone, or olanzapine (10–500 μM), significantly increased DA efflux in the mPFC. Local mPFC perfusion of telenzepine (0.1 μM) prevented increases in mPFC DA efflux induced by systemic administration of AC260584 (10 mg/kg), NDMC (20 mg/kg), and clozapine (10 mg/kg), but not by risperidone (1.0 mg/kg) or olanzapine (10 mg/kg). However, local mPFC perfusion of WAY-100635 (0.1 μM) prevented mPFC DA efflux induced by clozapine, risperidone, and olanzapine, but not by AC260584 or NDMC. These results suggest that the AC260584-, NDMC-, and clozapine-induced DA efflux in the mPFC is mediated directly by mPFC M1 receptors. The American Society for Pharmacology and Experimental Therapeutics