11494398

pubmed:Citation

4

Nicotine and other constituents of tobacco smoke elevate dopamine (DA) and serotonin (5-HT) levels in brain and may cause homeostatic adaptations in DA and 5-HT transporters. Since sex steroids alter DA and 5-HT transporter expression, the effects of smoking on DA and 5-HT transporter availability may differ between sexes. In the present study, DA and 5-HT transporter availabilities were quantitated using single photon emission computed tomography (SPECT) imaging approximately 22 h after bolus administration of [123I]beta-CIT, an analog of cocaine which labels DA and 5-HT transporters. Forty-two subjects including 21 pairs of age-, race-, and gender-matched healthy smokers and nonsmokers (12 female and 9 male pairs) were imaged. Regional uptake was assessed by the outcome measures, V3", which is the ratio of specific (i.e., ROI-cerebellar activity) to nondisplaceable (cerebellar) activity, and V3, the ratio of specific to free plasma parent. Overall, striatal and diencephalic [123I]beta-CIT uptake was not altered by smoking, whereas brainstem [123I]beta-CIT uptake was modestly higher (10%) in smokers vs. nonsmokers. When subgrouped by sex, regardless of smoking status, [123I]beta-CIT uptake was higher in the striatum (10%), diencephalon (15%), and brainstem (15%) in females vs. males. The sex*smoking interaction was not significant in the striatum, diencephalon, or brainstem, despite the observation of 20% higher brainstem [123I]beta-CIT uptake in male smokers vs. nonsmokers and less than a 5% difference between female smokers and nonsmokers. The results demonstrate higher DA and 5-HT transporter availability in females vs. males and no overall effect of smoking with the exception of a modest elevation in brainstem 5-HT transporters in male smokers. Although these findings are preliminary and need validation with a more selective 5-HT transporter radiotracer, the results suggest that brainstem 5-HT transporters may be regulated by smoking in a sex-specific manner.

eng

IM

MEDLINE

0887-4476

Copyright 2001 Wiley-Liss, Inc.

15

NLM

275-84

pubmed-meshheading:11494398-Adult, pubmed-meshheading:11494398-Affect, pubmed-meshheading:11494398-Brain Stem, pubmed-meshheading:11494398-Carrier Proteins, pubmed-meshheading:11494398-Cocaine, pubmed-meshheading:11494398-Corpus Striatum, pubmed-meshheading:11494398-Dopamine Plasma Membrane Transport Proteins, pubmed-meshheading:11494398-Female, pubmed-meshheading:11494398-Humans, pubmed-meshheading:11494398-Iodine Radioisotopes, pubmed-meshheading:11494398-Male, pubmed-meshheading:11494398-Membrane Glycoproteins, pubmed-meshheading:11494398-Membrane Transport Proteins, pubmed-meshheading:11494398-Middle Aged, pubmed-meshheading:11494398-Nerve Tissue Proteins, pubmed-meshheading:11494398-Radiopharmaceuticals, pubmed-meshheading:11494398-Serotonin Plasma Membrane Transport Proteins, pubmed-meshheading:11494398-Sex Characteristics, pubmed-meshheading:11494398-Smoking, pubmed-meshheading:11494398-Tomography, Emission-Computed, Single-Photon

Sex differences in [123I]beta-CIT SPECT measures of dopamine and serotonin transporter availability in healthy smokers and nonsmokers.

Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't