title: Effects of nucleus accumbens amphetamine administration on performance in a delay discounting task.
abstract: Chronic administration of cocaine can cause pronounced and enduring cognitive alterations such as increases in impulsive choice. Chronic cocaine can also result in enhanced dopamine (DA) release in the nucleus accumbens (NAc) in response to reward-related cues. It is possible that this enhanced DA release in the NAc is a mechanism by which cocaine increases impulsive choice. To date, however, the specific role of DA in the NAc in impulsive choice is unclear. To begin to address this, rats received acute microinjections of the indirect DA agonist amphetamine directly into the NAc prior to testing in a delay discounting task in which rats chose between a small, immediate and a large, delayed food reward. When delays to the large reward increased within test sessions, amphetamine increased choice of the large reward. When delays decreased within test sessions, however, amphetamine decreased choice of the large reward. These findings suggest that, rather than specifically mediating impulsive choice, DA neurotransmission in the NAc is necessary for flexible adaptation of choice strategies in the presence of shifting reward contingencies. These results further indicate that enhancements in NAc DA release likely do not account for lasting increases in impulsive choice caused by chronic cocaine.
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States. Electronic address: orsini@ufl.edu.
authors.forename: Caitlin A
authors.initials: CA
authors.lastname: Orsini
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 1 Church St., Fl7, New Haven, CT, 06510, United States.
authors.forename: Marci R
authors.initials: MR
authors.lastname: Mitchell
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States.
authors.forename: Sara C
authors.initials: SC
authors.lastname: Heshmati
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States.
authors.forename: Kristy G
authors.initials: KG
authors.lastname: Shimp
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Spurrell
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States; Department of Neuroscience, University of Florida College of Medicine, P.O. Box 100244, Gainesville, FL, 32610-0244, United States; Center for Addiction Research and Education, University of Florida, United States.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Bizon
authors.affiliation: Department of Psychiatry, University of Florida College of Medicine, P.O. Box 100256, Gainesville, FL, 32610-0256, United States; Department of Neuroscience, University of Florida College of Medicine, P.O. Box 100244, Gainesville, FL, 32610-0244, United States; Department of Psychology, University of Florida, United States; Center for Addiction Research and Education, University of Florida, United States. Electronic address: setlow@ufl.edu.
authors.forename: Barry
authors.initials: B
authors.lastname: Setlow
mesh_terms: D000661:Amphetamine / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D065786:Delay Discounting / Q000187:drug effects* / Q000502:physiology; D004298:Dopamine / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007175:Impulsive Behavior / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D011581:Psychological Tests; D020318:Rats, Long-Evans; D012201:Reward
chemical_list: D015259:Dopamine Agents; D000661:Amphetamine; D004298:Dopamine
keywords: Amphetamine; Delay discounting; Dopamine; Impulsive choice; Intertemporal choice; Nucleus accumbens