Serotonin transporter distribution and density in the cerebral cortex of alcoholic and nonalcoholic comparison subjects:: A whole-hemisphere autoradiography study

Objective: Lesions of the medial prefrontal cortex and dysfunctions in serotonin turnover are two well-established factors associated with impulsive and sociopathic behaviors, but no firm neuroanatomical data have linked these pathophysiological findings. The aims of this study were to identify putative areas in the human brain that are rich in serotonin transporter sites, particularly within the medial prefrontal cortex, and to determine whether serotonin transporter density in this area is altered among alcoholic subjects. Method: Serotonin transporter density was measured among 17 alcoholic and 10 nonalcoholic comparison subjects by postmortem whole-hemisphere autoradiography with [H-3]citalopram. Results: In the human cerebral cortex, serotonin transporter binding sites were concentrated in the perigenual anterior cingulate cortex. Substantially sparser serotonin transporter density (up to 35%) was observed in the perigenual anterior cingulate cortex of alcoholic subjects in relation to nonalcoholic comparison subjects. After adjustment for age and postmortem delay, this finding remained statistically significant. Conclusions: A lower serotonin transporter density among the alcoholic subjects was observed, specifically in the so-called "affect" region, suggesting an association between ethanol addiction and dysfunctional serotonergic neurotransmission in this area.