Lack of effect of acute dopamine precursor depletion in nicotine-dependent smokers.

ABSTRACT

RATIONALE Nicotine increases dopamine (DA) release but its role in nicotine dependence remains unclear. OBJECTIVE: To assess the role of DA in nicotine craving and self-administration using acute phenylalanine/tyrosine depletion (APTD). METHODS: Fifteen nicotine-dependent men ingested, a minimum of 3days apart, a nutritionally balanced amino acid (AA) mixture (BAL), a mixture deficient in the catecholamine precursors, phenylalanine and tyrosine, and APTD followed by the immediate DA precursor, L-DOPA. Beginning 3h after ingestion of the AA mixture, subjects smoked 4 cigarettes. Craving, mood, and other aspects of subjective state were assessed with self-report scales. Smoking puff topography was measured with a computerized flowmeter. RESULTS: APTD did not change smoking puff topography, cigarette craving, or subjective effects of smoking. CONCLUSIONS: The findings suggest that in nicotine-dependent smokers craving for cigarettes, subjective effects of nicotine, and the self-administration of freely available cigarettes are largely unrelated to acute changes in DA neurotransmission.