Striatal and extrastriatal dopamine D2 receptor availability as assessed by [18F]fallypride and PET in patients with alcohol use disorder

Abstract

Dopaminergic pathways are implicated in substance use disorders. Molecular imaging revealed reductions in dopamine D2 receptor availability in the striatum of withdrawn abusers of cocaine; corresponding results in alcoholics have been inconsistent so far. Here, we used [18F]fallypride to investigate D2 receptor availability in patients with alcohol use disorder (AUD) before and after undergoing a detoxification protocol. 17 patients (44 ± 5y) with AUD were scanned with 180 MBq [18F]fallypride upon hospital admission and after detoxification. Four patients with long term abstinence were rescanned at one year. The control group consisted of age-matched controls. Dynamic PET recordings were used for VOI-based and voxel-wise analyses of striatal and extrastriatal [18F]fallypride binding potential (BPND). In patients mean striatal BPND at baseline was 15.7 ± 3.6, similar to healthy controls (16.8 ± 3.0). BPND was lower in thalamus, hippocampus, insular and temporal cortex (p < 0.05). There were inverse correlations of BPND with age (r-0.45) and daily alcohol consumption (r-0.2). Age-dependence of BPND was pronounced in the patients. BPND was unaltered at short term follow-up, but increased by 30% at one year follow up. VOI-based PET revealed extrastriatal group differences in D2 receptor availability. BPND increased in patients with long term follow up, suggesting reversibility of receptor changes. Regressions with age suggest an accelerated loss of D2 receptors in patients with AUD.