title: Amphetamine-induced increases in extracellular dopamine, drug wanting, and novelty seeking: a PET/[11C]raclopride study in healthy men.
abstract: Eight healthy men underwent two positron emission tomography (PET) [11C]raclopride scans, one following placebo, the second following d-amphetamine (0.30 mg/kg, p.o.). PET data were analyzed using: (1) brain parametric maps to statistically generate regions of significant change; and (2) a priori identified regions of interest (ROI) manually drawn on each individual's co-registered magnetic resonance (MR) images. Compared with placebo, d-amphetamine decreased [11C]raclopride binding potential (BP) with significant effects in ventral but not dorsal striatum. Change in BP in the statistically generated cluster correlated with self-reported drug-induced 'drug wanting' (r = 0.83, p =.01) and the personality trait of Novelty Seeking-Exploratory Excitability (r = 0.79, p =.02). The same associations were seen in the manually drawn ROI in ventral striatum but not in dorsal putamen or caudate. Changes in extracellular dopamine (DA) did not correlate with mood. Mesolimbic DA might mediate interest in obtaining reward rather than reward, per se. Individual differences in amphetamine-induced DA release might be related to predispositions to drug and novelty seeking.
authors.affiliation: Department of Psychiatry, McGill University, Montréal, Québec, Canada. marco.leyton@mcgill.ca
authors.forename: Marco
authors.initials: M
authors.lastname: Leyton
authors.forename: Isabelle
authors.initials: I
authors.lastname: Boileau
authors.forename: Chawki
authors.initials: C
authors.lastname: Benkelfat
authors.forename: Mirko
authors.initials: M
authors.lastname: Diksic
authors.forename: Glen
authors.initials: G
authors.lastname: Baker
authors.forename: Alain
authors.initials: A
authors.lastname: Dagher
mesh_terms: D000328:Adult; D000661:Amphetamine / Q000494:pharmacology*; D000704:Analysis of Variance; D016739:Behavior, Addictive / Q000000981:diagnostic imaging / Q000378:metabolism*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000096:biosynthesis*; D005106:Exploratory Behavior / Q000187:drug effects* / Q000502:physiology; D005110:Extracellular Space / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D020891:Raclopride / Q000378:metabolism*; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: D020891:Raclopride; D000661:Amphetamine; D004298:Dopamine