In this Viewpoint, we highlight the history of positron emission tomography (PET) radiotracer development to quantify changes in monoamine oxidase (MAO)-A and -B enzyme expression or activity. MAO-A and MAO-B are critical for understanding monoaminergic pathways in psychiatric addiction disorders, and more recently in neurodegenerative disorders with MAO-B expression in astrogliosis. Unique radiochemical innovations have been shown for neuroimaging of MAOs including the clinical translation of irreversible propargylamine-based suicide inhibitors, application of deuterium-substitution to slow down metabolism, development of trapped metabolite imaging agents, and unique 11C-carbonylation chemistry toward novel high-affinity reversibly binding inhibitors.
Keywords: MAO-A; MAO-B; Monoamine oxidase; PET; carbon-11; fluorine-18.