title: Individual variation in incentive salience attribution and accumbens dopamine transporter expression and function.
abstract: Cues (conditioned stimuli; CSs) associated with rewards can come to motivate behavior, but there is considerable individual variation in their ability to do so. For example, a lever-CS that predicts food reward becomes attractive and wanted, and elicits reward-seeking behavior, to a greater extent in some rats ('sign-trackers'; STs) than others ('goal-trackers'; GTs). Variation in dopamine (DA) neurotransmission in the nucleus accumbens (NAc) core is thought to contribute to such individual variation. Given that the DA transporter (DAT) exerts powerful regulation over DA signaling, we characterized the expression and function of the DAT in the accumbens of STs and GTs. STs showed greater DAT surface expression in ventral striatal synaptosomes than GTs, and ex vivo fast-scan cyclic voltammetry recordings of electrically evoked DA release confirmed enhanced DAT function in STs, as indicated by faster DA uptake, specifically in the NAc core. Consistent with this, systemic amphetamine (AMPH) produced greater inhibition of DA uptake in STs than in GTs. Furthermore, injection of AMPH directly into the NAc core enhanced lever-directed approach in STs, presumably by amplifying the incentive value of the CS, but had no effect on goal-tracking behavior. On the other hand, there were no differences between STs and GTs in electrically-evoked DA release in slices, or in total ventral striatal DA content. We conclude that greater DAT surface expression may facilitate the attribution of incentive salience to discrete reward cues. Investigating this variability in animal sub-populations may help explain why some people abuse drugs while others do not.
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
authors.forename: Bryan F
authors.initials: BF
authors.lastname: Singer
authors.affiliation: Department of Pharmacology, University of Michigan School of Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Bipasha
authors.initials: B
authors.lastname: Guptaroy
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
authors.forename: Curtis J
authors.initials: CJ
authors.lastname: Austin
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
authors.forename: Isabella
authors.initials: I
authors.lastname: Wohl
authors.affiliation: Department of Psychology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Vedran
authors.initials: V
authors.lastname: Lovic
authors.affiliation: Psychology Department, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Jillian L
authors.initials: JL
authors.lastname: Seiler
authors.affiliation: Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA.
authors.forename: Roxanne A
authors.initials: RA
authors.lastname: Vaughan
authors.affiliation: Department of Pharmacology, University of Michigan School of Medicine, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Gnegy
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
authors.forename: Terry E
authors.initials: TE
authors.lastname: Robinson
authors.affiliation: Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
authors.forename: Brandon J
authors.initials: BJ
authors.lastname: Aragona
mesh_terms: D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D003214:Conditioning, Classical; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D005089:Exocytosis; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D013574:Synaptosomes / Q000378:metabolism
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D000661:Amphetamine; D004298:Dopamine
keywords: Sprague-Dawley rat; amphetamine; conditioning; sign-tracking; voltammetry