Citation

Leyton M, aan het Rot M, Booij L, Baker GB, Young SN, Benkelfat C. J. Psychiatry Neurosci. 2007; 32(2): 129-136.

Affiliation

Department of Psychiatry, McGill University, Montréal, Que. marco.leyton@mcgill.ca

Copyright

(Copyright © 2007, Canadian Medical Association)

DOI

unavailable

PMID

17353942

PMCID

PMC1810580

Abstract

OBJECTIVE: Midbrain dopamine transmission is thought to regulate responses to rewarding drugs and drug-paired stimuli; however, the exact contribution, particularly in humans, remains unclear. In the present study, we tested whether decreasing dopamine synthesis, as produced by acute phenylalanine/tyrosine depletion (APTD), would alter responses to the stimulant drug, d-amphetamine.

METHODS: On 3 separate days, 14 healthy men received d-amphetamine (0.3 mg/kg, given orally) plus a nutritionally balanced amino acid mixture, the phenylalanine/tyrosine-deficient mixture or the phenylalanine/tyrosine-deficient mixture followed by the immediate dopamine precursor, L-DOPA (Sinemet, 2 x 100 mg/25 mg). Responses to these treatments were assessed with visual analog scales, the Profile of Mood States, and a computerized Go/No-Go task.

RESULTS: d-Amphetamine elicited its prototypical subjective effects, but these were not altered by APTD. In comparison, APTD significantly increased commission errors on the Go/No-Go task and did so uniquely in conditions where subjects were rewarded for making correct responses; this effect of APTD was prevented by L-DOPA.

CONCLUSIONS: Together these results support the hypothesis that, in healthy men, dopamine is not closely linked to euphorogenic effects of abused substances but does affect the salience of reward-related cues and the ability to respond to them preferentially.

Language: en