Muscarinic receptor antagonism causes a functional alteration in nucleus accumbens μ-opiate-mediated feeding behavior

Intra-nucleus accumbens (Acb) infusion of cholinergic muscarinic antagonist, scopolamine (10 μg/0.5 μl), markedly reduced fat intake elicited by intra-Acb treatment of the μ-opioid receptor agonist, DAMGO, with 30 min and 4 h pretreatment intervals. Intra-Acb scopolamine infusions also reduced food intake in food-deprived rats, but not water intake in water-deprived rats. Hence, Acb muscarinic manipulations exhibit some specificity for feeding, perhaps via interactions with the striatal opioid system.