title: Effects of co-administration of 2-arachidonylglycerol (2-AG) and a selective µ-opioid receptor agonist into the nucleus accumbens on high-fat feeding behaviors in the rat.
abstract: Previous research has demonstrated that the nucleus accumbens is a site where opioids and cannabinoids interact to alter feeding behavior. However, the influence of the endocannabinoid 2-arachidonylglycerol (2-AG) on the well-characterized model of intra-accumbens opioid driven high-fat feeding behavior has not been explored. The present experiments examined high-fat feeding associated behaviors produced by the interaction of 2-AG and the μ-opioid receptor agonist DAla(2),N,Me-Phe(4),Gly-ol(5)-enkaphalin (DAMGO) administered into the nucleus accumbens. Sprague-Dawley rats were implanted with bilateral cannulae aimed at the nucleus accumbens and were co-administered both a sub-threshold dose of 2-AG (0 or 0.25 μg/0.5 μl/side) and DAMGO (0, 0.025 μg or 0.25 μg/0.5 μl/side) in all dose combinations, and in a counterbalanced order. Animals were then immediately allowed a 2h-unrestricted access period to a palatable high-fat diet. Consumption, number and duration of food hopper entries, and locomotor activity were all monitored. DAMGO treatment led to an increase in multiple behaviors, including consumption, duration of food hopper entry, and locomotor activity. However, combined intra-accumbens administration of DAMGO and a subthreshold dose of 2-AG led to a significant increase in number of food hopper entries and locomotor activity, compared to DAMGO by itself. The results confirm that intra-accumbens administration of subthreshold dose of the endogenous cannabinoid 2-AG increases the DAMGO-induced approach and locomotor behaviors associated with high-fat feeding.
authors.affiliation: Department of Psychological Sciences, University of Missouri, Columbia, MO, United States; Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States; Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO, United States.
authors.forename: Kyle E
authors.initials: KE
authors.lastname: Parker
authors.affiliation: Department of Psychological Sciences, University of Missouri, Columbia, MO, United States; Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.
authors.forename: Jordan G
authors.initials: JG
authors.lastname: McCall
authors.affiliation: Department of Psychological Sciences, University of Missouri, Columbia, MO, United States; Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.
authors.forename: Sophia R
authors.initials: SR
authors.lastname: McGuirk
authors.affiliation: Department of Psychological Sciences, University of Missouri, Columbia, MO, United States; Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.
authors.forename: Seema
authors.initials: S
authors.lastname: Trivedi
authors.affiliation: Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States.
authors.forename: Dennis K
authors.initials: DK
authors.lastname: Miller
authors.affiliation: Department of Psychological Sciences, University of Missouri, Columbia, MO, United States; Christopher Bond Life Sciences Center, University of Missouri, Columbia, MO, United States. Electronic address: willm@missouri.edu.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Will
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D063386:Cannabinoid Receptor Agonists / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage*; D063388:Endocannabinoids / Q000494:pharmacology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D005989:Glycerides / Q000494:pharmacology*; D008297:Male; D008845:Microinjections; D009714:Nucleus Accumbens / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000701:Analgesics, Opioid; D001095:Arachidonic Acids; D063386:Cannabinoid Receptor Agonists; D004041:Dietary Fats; D063388:Endocannabinoids; D005989:Glycerides; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; C094503:glyceryl 2-arachidonate
keywords: 2-arachidonylglycerol; Approach; Cannabinoid; Consumption; DAMGO; Feeding; High fat; Nucleus accumbens; Opioid; Palatable food; Reward