Short ReportDeletion of mu opioid receptors reduces palatable solution intake in a mouse model of binge eatingAwad, Gaëllea; Roeckel, Laurie-Annea; Massotte, Dominiqueb; Olmstead, Mary C.c; Befort, Katiaa Author Information aLaboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Centre de la Recherche Nationale Scientifique, Université de Strasbourg Faculté de Psychologie bCentre de la Recherche Nationale Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives (INCI), Strasbourg, France cDepartment Psychology, Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada Received 6 January 2019 Accepted as revised 5 June 2019 Correspondence to Mary C. Olmstead, Department of Psychology, Queen’s University, Kingston, ON K7L 3N6, Canada, E-mail: [email protected] Behavioural Pharmacology 31(2&3):p 249-255, April 2020. | DOI: 10.1097/FBP.0000000000000496 Buy Metrics Abstract Binge eating in humans is driven by hedonic properties of food, suggesting that brain reward systems may contribute to this behaviour. We examined the role of mu opioid receptors (MOP) in binge eating by examining sweet solution intake in mice with genetic deletion of the MOP. Wildtype and MOP knockout mice had 4 hours access to food in the home cage combined with limited (4 hours) access to sucrose (17.1% w/v) or saccharin (0.09% w/v), or continuous (24 hours) access to sucrose. Only limited access groups exhibited binge intake, measured as increased solution consumption during the first hour. Knockout mice consumed less solution and food during the first hour as well as less food each day compared with wildtype mice. Limited access groups consumed more food and gained more weight than continuous access groups, and the effect was magnified in saccharin-consuming mice. Indeed, the increased food consumption in animals given limited access to saccharin was so excessive that caloric intake of this group was significantly higher than either of the sucrose groups (limited or continuous access). Within this group, females consumed more food per bodyweight than males, highlighting important sex differences in feeding behaviours under restricted access schedules. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.