title: Effects of CB1 and CRF1 receptor antagonists on binge-like eating in rats with limited access to a sweet fat diet: lack of withdrawal-like responses.
abstract: Positive reinforcement (e.g., appetitive, rewarding properties) has often been hypothesized to maintain excessive intake of palatable foods. Recently, rats receiving intermittent access to high sucrose diets showed binge-like intake with withdrawal-like signs upon cessation of access, suggesting negative reinforcement mechanisms contribute as well. Whether intermittent access to high fat diets also produces withdrawal-like syndromes is controversial. The present study therefore tested the hypothesis that binge-like eating and withdrawal-like anxiety would arise in a novel model of binge eating based on daily 10-min access to a sweet fat diet (35% fat kcal, 31% sucrose kcal). Within 2-3 weeks, female Wistar rats developed binge-like intake comparable to levels seen previously for high sucrose diets (~40% of daily caloric intake within 10 min) plus excess weight gain and adiposity, but absent increased anxiety-like behavior during elevated plus-maze or defensive withdrawal tests after diet withdrawal. Binge-like intake was unaffected by pretreatment with the corticotropin-releasing factor type 1 (CRF(1)) receptor antagonist R121919, and corticosterone responses to restraint stress did not differ between sweet-fat binge rats and chow-fed controls. In contrast, pretreatment with the cannabinoid type 1 (CB(1)) receptor antagonist SR147778 dose-dependently reduced binge-like intake, albeit less effectively than in ad lib chow or sweet fat controls. A priming dose of the sweet fat diet did not precipitate increased anxiety-like behavior, but rather increased plus-maze locomotor activity. The results suggest that CB(1)-dependent positive reinforcement rather than CRF(1)-dependent negative reinforcement mechanisms predominantly maintain excessive intake in this limited access model of sweet-fat diet binges.
authors: Committee on the Neurobiology of Addictive Disorders, SP30-2400, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA.|Neurosciences Graduate Program, University of California, San Diego, 9500 Gilman Dr 0634, La Jolla, CA 92093, USA.
authors: Sarah L
authors: SL
authors: Parylak
authors: Committee on the Neurobiology of Addictive Disorders, SP30-2400, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA.|Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E Concord St, R-618, Boston, MA 02118, USA.
authors: Pietro
authors: P
authors: Cottone
authors: Committee on the Neurobiology of Addictive Disorders, SP30-2400, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA.|Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, 72 E Concord St, R-618, Boston, MA 02118, USA.
authors: Valentina
authors: V
authors: Sabino
authors: Chemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, 5625 Fishers Lane, Bethesda, MD 20892, USA.
authors: Kenner C
authors: KC
authors: Rice
authors: Committee on the Neurobiology of Addictive Disorders, SP30-2400, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, CA 92037, USA.|Neurosciences Graduate Program, University of California, San Diego, 9500 Gilman Dr 0634, La Jolla, CA 92093, USA.
authors: Eric P
authors: EP
authors: Zorrilla
mesh_terms: D000818:Animals; D001007:Anxiety / Q000139:chemically induced / Q000523:psychology; D002032:Bulimia / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology; D063387:Cannabinoid Receptor Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D003345:Corticosterone / Q000378:metabolism; D004041:Dietary Fats / Q000009:adverse effects*; D019422:Dietary Sucrose / Q000009:adverse effects*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D018782:Maze Learning / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology / Q000627:therapeutic use*; D011720:Pyrazoles / Q000494:pharmacology / Q000627:therapeutic use*; D011743:Pyrimidines / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000502:physiology
chemical_list: D063387:Cannabinoid Receptor Antagonists; D004041:Dietary Fats; D019422:Dietary Sucrose; D010880:Piperidines; D011720:Pyrazoles; D011743:Pyrimidines; C412383:R 121919; D018019:Receptors, Corticotropin-Releasing Hormone; C492668:surinabant; D003345:Corticosterone