Nucleus accumbens serotonin transporters in alcoholics measured by whole-hemisphere autoradiography

Nucleus accumbens (NAC) is regulated by the dopaminergic and serotonergic pathways, and it is a brain area with a crucial role in the rewarding effects of ethanol. In this preliminary study, possible alterations of [3H]citalopram binding to serotonin transporter (SERT) were evaluated in the NAC of Cloninger type 1 and 2 alcoholics (nine and seven subjects, respectively), and nonalcoholic controls (10 subjects) by human postmortem whole-hemisphere autoradiography.The [3H]citalopram binding in the NAC was 35% higher in the alcoholics than in the controls; in the type 1 alcoholics, the binding was 54% and in the type 2 alcoholics it was 17% higher. Although the effect size showed medium effects (0.49–0.60), the results did not reach statistical significance due to large standard deviations. The [3H]citalopram binding declined significantly with age in the controls, but not in the alcoholics. In the controls, there was a significant positive correlation between the [3H]citalopram binding in the NAC and in the anterior cingulate gyrus, an area in which the [3H]citalopram binding has been shown to be lower among alcoholics. On the contrary, a significant negative correlation was observed in the type 2 alcoholics and no correlation in the type 1 alcoholics. In addition, there was a strong tendency toward a positive correlation between the SERT and dopamine transporter binding in the type 2 alcoholics, but not in the other groups. These preliminary results suggest a differential monoaminergic imbalance in type 1 and 2 alcoholism in brain areas important for the regulation of motivation, reward, and reinforcement.