PET uses radioactively labeled molecules called radiotracers to measure receptors and other chemicals, as well as fluctuations in neurotransmitter levels, in the living brain (E. D. Morris, Lucas, & Cosgrove, 2013). Many radiotracers have been designed to bind to dopamine (DA) and serotonin (5HT) receptors, among numerous others, and are used to measure receptor availability. These techniques have implications for identifying SG differences in neurochemical mechanisms underlying substance use disorders and relating brain mechanisms to important clinical correlates of addiction (Verplaetse, Morris, McKee, & Cosgrove, 2018), including AUD. We first present studies that focused on the dopamine system, and then turn to studies that focused on the opioid system.
