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Eur J Neurosci. 2016 Mar;43(5):662-70. doi: 10.1111/ejn.13134. Epub 2016 Jan 7.

Individual variation in incentive salience attribution and accumbens dopamine transporter expression and function.

Author information

1
Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA.
2
Department of Pharmacology, University of Michigan School of Medicine, University of Michigan, Ann Arbor, MI, USA.
3
Department of Psychology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
4
Psychology Department, University of Illinois at Chicago, Chicago, IL, USA.
5
Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA.

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.

KEYWORDS:

Sprague-Dawley rat; amphetamine; conditioning; sign-tracking; voltammetry

PMID:
26613374
PMCID:
PMC4783234
[Available on 2017-03-01]
DOI:
10.1111/ejn.13134
[Indexed for MEDLINE]
Free PMC Article

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