Serotonin 1B Receptor Imaging in Alcohol Dependence

BackgroundAlthough animal models suggest that alcohol dependence (AD) is associated with elevations in the number of serotonin 1B receptors (5-HT1BR), 5-HT1BR levels have not been investigated in people with AD. The selective 5-HT1BR antagonist radioligand, [11C]P943, permits in vivo assessment of central 5-HT1BR binding potential (BPND) with positron emission tomography. Because of its central role in AD, we were particularly interested in ventral striatal 5-HT1BR BPND values.MethodsTwelve medication-free, recently abstinent (at least 4 weeks) patients with AD (mean age 35.2 ± 10.2 years, 5 women) and 12 healthy control subjects (HC) (mean age 30.6 ± 9.2 years, 5 women) completed [11C]P943 positron emission tomography on a high-resolution research tomograph. Individual magnetic resonance imaging scans were collected to exclude individuals with anatomical abnormalities and for coregistration. Imaging data were analyzed with a multilinear reference tissue model.ResultsVentral striatal 5-HT1BR BPND values (2.01 ± .57% and 1.55 ± .09%, respectively; 29% between-group difference, p = .006) were increased in AD compared with HC subjects. No influence of demographic or clinical variables or amount of injected radiotracer was observed.ConclusionsThis study provides the first evidence that AD in humans is, like in rodent models, associated with increased levels of ventral striatal 5-HT1BRs.