Sex, smoking and striatal dopamine

Objectives Male smokers (SM) have lower DA D2/D3 receptor availability (RA) in putamen (PU) than nonsmokers (NSM)1. We extended this work, by studying women.

Methods SM (both sexes, equal cigarette use and dependence)and NSM were tested with PET and [18F]fallypride to assess D2/D3 RA in the caudate (CA) and PU (SRTM2 model). Data were analyzed with MANCOVA, ANOVAs and t-tests.

Results The main effect of sex and its interaction with smoking were significant (MANOVA). Sex effects were significant (CA & PU), with a significant interaction in PU (ANOVA). Sex differences were significant only in SM.

Conclusions Higher D2/D3 RA in women is a new finding. The results support evidence for lower D2/D3 RA in SM1, but was nonsignificant. As women have higher striatal DA transporter availability than men2, lack of D2/D3 downregulation with smoking in women may reflect more rapid DA reuptake.

Research Support NIH DA020726,DA02253

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