Muscarinic, but not nicotinic, acetylcholine receptor blockade in the ventral tegmental area attenuates cue-induced sucrose-seeking

• Published in: Behavioural brain research Vol. 291; pp. 372 - 376
• Main Authors: Addy, Nii A., Nunes, Eric J., Wickham, Robert J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.09.2015
• Subjects: Animals; Appetitive Behavior - drug effects; Appetitive Behavior - physiology; Cohort Studies; Conditioning, Operant - drug effects; Conditioning, Operant - physiology; Cues; Dietary Sucrose - administration & dosage; Dose-Response Relationship, Drug; Feeding Behavior - drug effects; Feeding Behavior - physiology; Male; Mecamylamine; Mecamylamine - pharmacology; Mesolimbic dopamine system; Motivation - drug effects; Motivation - physiology; Muscarinic Antagonists - pharmacology; Neuropsychological Tests; Nicotinic Antagonists - pharmacology; NMDA receptor; Rats, Sprague-Dawley; Receptors, Muscarinic - metabolism; Receptors, Nicotinic - metabolism; Reward; Reward-seeking behavior; Scopolamine; Scopolamine - pharmacology; Self Administration; Ventral Tegmental Area - drug effects; Ventral Tegmental Area - metabolism; Mesolimbic dopamine system; Scopolamine; NMDA receptor; Reward-seeking behavior; Mecamylamine
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2015.05.036

•We examined cue-induced sucrose-seeking during blockade of VTA AChRs or NMDARs.•VTA scopolamine infusion attenuated cue-induced sucrose-seeking.•VTA mecamylamine infusion did not alter cue-induced sucrose-seeking.•VTA AP5 infusion did not alter cue-induced sucrose-seeking. The mesolimbic dopamine (DA) system is known to play a role in cue-mediated reward-seeking for natural rewards and drugs of abuse. Specifically, cholinergic and glutamatergic receptors in the ventral tegmental area (VTA) have been shown to regulate cue-induced drug-seeking. However, the potential role of these VTA receptors in regulating cue-induced reward seeking for natural rewards is unknown. Here, we examined whether blockade of VTA acetylcholine receptors (AChRs) and N-methyl-d-aspartate receptors (NMDARs) would alter cue-induced sucrose seeking in male Sprague-Dawley rats. Subjects underwent 10 days of sucrose self-administration training (fixed ratio 1 schedule) followed by 7 days of forced abstinence. On withdrawal day 7, rats received bilateral VTA infusion of vehicle, the muscarinic AChR antagonist scopolamine (2.4 or 24μg/side), the nicotinic AChR antagonist mecamylamine (3 or 30μg/side), or the NMDAR antagonist AP-5 (0.1 or 1μg/side) immediately prior to examination of cue-induced sucrose-seeking. Scopolamine infusion led to robust attenuation, but did not completely block, sucrose-seeking behavior. In contrast, VTA administration of mecamylamine or AP-5 did not alter cue-induced sucrose-seeking. Together, the data suggest that VTA muscarinic AChRs, but not nicotinic AChRs nor NMDARs, facilitate the ability of food-associated cues to drive seeking behavior for a food reward.