PET Imaging of AMPARs Shows Ketamine Effect

Background: Patients with major depressive disorder (MDD) do not respond to routine antidepressant medications in up to 30% of cases. Ketamine has become a next in line therapy for these patients, but its therapeutic action has not been well understood. A receptor, called glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR), has been shown to relate to the antidepressant effect of ketamine in animals. To study this effect in humans, the authors developed a radiolabeled PET agent called [ 11 C]K-2 to measure the density of AMPARs in the human brain. Objective: To determine the antidepressant effect of ketamine on brain receptors by using their radiolabeled PET agent called [ 11 C]K-2. Methods: Patients with MDD who had a 11 C]K-2 and imaged 30 to 50 minutes later. The AMPAR density was determined by the standardized uptake value ratio (SUVR; SUVR 30-50 ) uptake calculation. Results: When the SUVR 30-50 was compared to the Montgomery-Åsberg Depre more...