Lower serotonin transporter binding in caudate in alcoholics

Abstract

Dorsal striatum is regulated by the serotonergic system, and it is a brain area with a role in the development of obsessive thought patterns, which may be related to addiction. In this study, possible alterations of [(3)H]citalopram binding to serotonin transporter (SERT) were evaluated in the dorsal striatum of Cloninger type 1 and 2 alcoholics, and nonalcoholic control subjects by postmortem whole-hemisphere autoradiography in humans. The SERT binding was significantly lower (-26%, effect size 1.74) in the caudate body of alcoholics. The SERT binding tended to be lower also in the other parts of the dorsal striatum in alcoholics, but the results did not reach significance. In addition, there was a significant positive correlation, especially in type 1 alcoholics, between the SERT binding in the body of the caudate and in the perigenual anterior cingulate cortex, an area in which the SERT binding has been shown to be lower among alcoholics. These results give preliminary evidence to suggest that the SERT binding in the dorsal striatum may be lower in alcoholics, and that the serotonergic system may be affected in cortical and striatal areas simultaneously. The cortico-striatal-thalamic axis may have an important role in fully developed addictions and the characterization of these correlations within the serotonergic system may lead to a better understanding of the anatomical dynamics underlying the neurochemistry of alcoholism.