Lack of effect of acute dopamine precursor depletion in nicotine-dependent smokers.
BACKGROUND
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.
Casey
Kevin F
KF
Department of Psychiatry, McGill University, 1033 Pine Avenue West, Montreal, Quebec, Canada H3A 1A1.
Benkelfat
Chawki
C
Young
Simon N
SN
Leyton
Marco
M
D000328:Adult; D018753:Diet, Protein-Restricted / Q000379:methods*; D004298:Dopamine / Q000502:physiology*; D015259:Dopamine Agents / Q000008:administration & dosage; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D010147:Pain Measurement / Q000379:methods; D010649:Phenylalanine / Q000172:deficiency; D012646:Self Administration; D011795:Surveys and Questionnaires; D013997:Time Factors; D014029:Tobacco Use Disorder / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D014443:Tyrosine / Q000172:deficiency
D015259:Dopamine Agents; D014443:Tyrosine; D007980:Levodopa; D010649:Phenylalanine; D004298:Dopamine