title: Persistent palatable food preference in rats with a history of limited and extended access to methamphetamine self-administration.
abstract: Recent studies have shown that when given a mutually exclusive choice between cocaine and palatable foods, most rats prefer the non-drug rewards over cocaine. Here, we used a discrete choice procedure to assess whether palatable food preference generalizes to rats with a history of limited (3 hours/day) or extended (6 or 9 hours/day) access to methamphetamine self-administration. On different daily sessions, we trained rats to lever-press for either methamphetamine (0.1-0.2 mg/kg/infusion) or palatable food (five pellets per reward delivery) for several weeks; regular food was freely available. We then assessed food-methamphetamine preference either during training, after priming methamphetamine injections (0.5-1.0 mg/kg), following a satiety manipulation (palatable food exposure in the home cage) or after 21 days of withdrawal from methamphetamine. We also assessed progressive ratio responding for palatable food and methamphetamine. We found that independent of the daily drug access conditions and the withdrawal period, the rats strongly preferred the palatable food over methamphetamine, even when they were given free access to the palatable food in the home cage. Intake of methamphetamine and progressive ratio responding for the drug, both of which increased or escalated over time, did not predict preference in the discrete choice test. Results demonstrate that most rats strongly prefer palatable food pellets over intravenous methamphetamine, confirming previous studies using discrete choice procedures with intravenous cocaine. Results also demonstrate that escalation of drug self-administration, a popular model of compulsive drug use, is not associated with a cardinal feature of human addiction of reduced behavioral responding for non-drug rewards.
authors.affiliation: Behavioral Neuroscience Research Branch, Intramural Research Program, NIH, DHHS, National Institute on Drug Abuse, Baltimore, MD, USA.
authors.forename: Daniele
authors.initials: D
authors.lastname: Caprioli
authors.affiliation: Behavioral Neuroscience Research Branch, Intramural Research Program, NIH, DHHS, National Institute on Drug Abuse, Baltimore, MD, USA.
authors.forename: Tamara
authors.initials: T
authors.lastname: Zeric
authors.affiliation: Behavioral Neuroscience Research Branch, Intramural Research Program, NIH, DHHS, National Institute on Drug Abuse, Baltimore, MD, USA.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Thorndike
authors.affiliation: Behavioral Neuroscience Research Branch, Intramural Research Program, NIH, DHHS, National Institute on Drug Abuse, Baltimore, MD, USA.|Neuropsychopharmacology Laboratory, Section Pharmacology, Department Public Health and Community Medicine, University of Verona, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Venniro
mesh_terms: D000818:Animals; D016739:Behavior, Addictive; D001522:Behavior, Animal / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology; D002755:Choice Behavior / Q000187:drug effects*; D003216:Conditioning, Operant; D004195:Disease Models, Animal; D005518:Food Preferences / Q000187:drug effects*; D008297:Male; D008694:Methamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D012646:Self Administration
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine
keywords: Discrete choice; drug priming; extended access; food satiety; limited access; palatable food; preference; progressive ratio; psychostimulants; self-administration