Dopaminergic responses alone are unlikely to fully account for the pleasure and reward experienced following acute alcohol consumption. Endogenous opioid levels rapidly increase in the nucleus accumbens and orbitofrontal cortex upon alcohol consumption, as demonstrated using PET imaging of [11C]carfentanil (Mitchell et al., 2012). Moreover, increased μ-opioid receptor availability in the ventral striatum of detoxified alcoholics correlates with self-reports of craving intensity (Heinz et al., 2005). These findings were supported in a separate study using the μ-opioid receptor tracer [11C]diprenorphine (Williams et al., 2009).
