title: Heroin self-administration: I. Incubation of goal-directed behavior in rats.
abstract: This study used heroin self-administration to investigate incubation of goal-directed heroin-seeking behavior following abstinence. Male Sprague-Dawley rats self-administered heroin on a fixed ratio 10 (FR10) schedule of reinforcement with licking of an empty spout serving as the operant behavior during 14 daily 3 h sessions. After this acquisition period, all rats received a 90 min extinction session following either 1 day or 14 days of home cage abstinence. When the extinction session occurred after only 1 day of home cage abstinence, rats with a history of heroin self-administration divided their responses equally between the previously "active" and "inactive" spouts. However, when the extinction session occurred following 14 days of home cage abstinence, the rats exhibited marked goal-directed heroin-seeking behavior by licking more on the previously "active" than "inactive" spout. These findings demonstrate that heroin-seeking behavior incubates over time, resulting in goal-directed heroin-seeking behavior in rats following 14 days but not 1 day of abstinence. Moreover, this facilitatory effect occurred in response to a different training schedule, lower total drug intake, and shorter periods of daily access than previously reported with heroin.
authors.affiliation: Department of Pharmacology, Pennsylvania State University College of Medicine, R130, 500 University Drive, Hershey, PA 17033, USA. kkuntz@psu.edu
authors.forename: Kara L
authors.initials: KL
authors.lastname: Kuntz
authors.forename: Robert C
authors.initials: RC
authors.lastname: Twining
authors.forename: Anne E
authors.initials: AE
authors.lastname: Baldwin
authors.forename: Kent E
authors.initials: KE
authors.lastname: Vrana
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Grigson
mesh_terms: D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D005108:Extinction, Psychological / Q000187:drug effects; D006040:Goals; D003932:Heroin / Q000008:administration & dosage / Q000494:pharmacology; D006556:Heroin Dependence / Q000523:psychology*; D008297:Male; D009294:Narcotics / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012646:Self Administration; D013375:Substance Withdrawal Syndrome / Q000523:psychology; D014868:Water Deprivation
chemical_list: D009294:Narcotics; D003932:Heroin