Amphetamine-Induced Increases in Extracellular Dopamine, Drug Wanting, and Novelty Seeking: A PET/[11C]Raclopride Study in Healthy Men

• Published in: Neuropsychopharmacology (New York, N.Y.) Vol. 27; no. 6; pp. 1027 - 1035
• Main Authors: Leyton, Marco, Boileau, Isabelle, Benkelfat, Chawki, Diksic, Mirko, Baker, Glen, Dagher, Alain
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.12.2002; Nature Publishing; Nature Publishing Group
• Subjects: Addiction; Adult; Amphetamine - pharmacology; Analysis of Variance; Behavior, Addictive - diagnostic imaging; Behavior, Addictive - metabolism; Biological and medical sciences; Corpus Striatum - diagnostic imaging; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Dopamine - biosynthesis; Exploratory Behavior - drug effects; Exploratory Behavior - physiology; Extracellular Space - diagnostic imaging; Extracellular Space - drug effects; Extracellular Space - metabolism; Humans; Magnetic Resonance Imaging - methods; Male; Medical sciences; Neuropharmacology; Nucleus accumbens; Pharmacology. Drug treatments; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Raclopride - metabolism; Reinforcement; Reward; Tomography, Emission-Computed - methods; Nucleus accumbens; Reinforcement; Reward; Addiction; Amphetamine derivatives; Human; Dopamine; Healthy subject; CNS stimulant; Psychotropic; Oral administration; Corpus striatum; Personality; Novelty Experiencing Scale; Biological activity; Amfetamine; Positron emission tomography; Brain (vertebrata)
• ISSN: 0893-133X; 1740-634X
• DOI: 10.1016/S0893-133X(02)00366-4

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.