Ketamine is the first glutamatergic agent in clinical use for major depression, but its primary target remains unclear. Further research is needed to develop more specific interventions with fewer side effects. Ketamine is a noncompetitive antagonist of the glutamatergic N-methyl-D-aspartate (NMDA) receptor. Here, we show that ketamine preferentially targets GluN2D-containing NMDA receptors on...