title: Effects of acute and chronic flunitrazepam on delay discounting in pigeons.
abstract: Delay to delivery of a reinforcer can decrease responding for that reinforcer and increase responding for smaller reinforcers that are available concurrently and delivered without delay; acute administration of drugs can alter responding for large, delayed reinforcers, although the impact of chronic treatment on delay discounting is not well understood. In this experiment, the effects of repeated administration of the benzodiazepine flunitrazepam were studied in 6 pigeons responding on one key to receive food that was delivered immediately and on a second key to receive a larger amount of food that was delivered following delays which increased across a single session. Pigeons responded predominantly for the large reinforcer when there were no delays and when delays were short; however, as delays increased, responding for the large reinforcer decreased. Acutely, flunitrazepam (0.32, 1.0 and 3.2 mg/kg) dose-dependently increased responding for the large reinforcer, shifting the discounting curve rightward and upward. Repeated administration of flunitrazepam (0.32, 1.0 and 3.2 mg/kg, each for six sessions, separated by one session during which vehicle was administered) did not markedly alter its effects on responding for the large reinforcer, indicating that the development of tolerance to this effect of flunitrazepam is modest under these conditions.
authors.affiliation: Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 7764, San Antonio, Texas 78229, USA.
authors.forename: Amy K
authors.initials: AK
authors.lastname: Eppolito
authors.forename: Charles P
authors.initials: CP
authors.lastname: France
authors.forename: Lisa R
authors.initials: LR
authors.lastname: Gerak
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001245:Association Learning / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D005445:Flunitrazepam / Q000494:pharmacology*; D007175:Impulsive Behavior / Q000523:psychology*; D007266:Inhibition, Psychological; D007273:Injections, Intramuscular; D009042:Motivation / Q000187:drug effects*; D012055:Reinforcement Schedule; D013998:Time Perception / Q000187:drug effects*
chemical_list: D014151:Anti-Anxiety Agents; D005445:Flunitrazepam