Mu-opioid receptor binding measured by [¹¹C]carfentanil positron emission tomography is related to craving and mood in alcohol dependence

Background: The endogenous opioid system has been linked to alcohol dependence through animal and human studies. We investigated the relationship between alcohol craving and brain mu opioid receptors (μ-OR) in alcohol-dependent subjects. Methods: Regional brain μ-OR binding potential (BP) was measured using [¹¹C]carfentanil positron emission tomography in eight male alcohol-dependent subjects undergoing alcohol withdrawal and eight matched control subjects. Self-reported alcohol craving, withdrawal, and mood were measured. Results: Lower μ-OR BP was associated with higher craving in the right dorsal lateral prefrontal cortex, the right anterior frontal cortex, and right parietal cortex. In these regions, alcoholics showed lower mean μ-OR BP compared with control subjects. Mu-OR BP in four other brain regions also correlated with craving, but there were no group differences in receptor binding potential. Mu-OR BP also correlated with depressive symptoms in five brain regions, three of which were identified in the craving analyses. Conclusions: Results show a strong functional relationship between alcohol craving, mood, and μ-OR binding in specific brain regions of recently abstinent, alcohol-dependent men.