for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Clinic
of Affective Disorders and General Psychiatry, University Hospital of
Psychiatry Zurich, Zurich, Switzerland; 3Cluster Languages of
Emotion, Freie Universitt Berlin, Berlin, Germany, Germany; 4Max Planck
Institute for Biological Cybernetics, Tbingen, Germany
Ketamine is a potent glutamatergic NMDA receptor antagonist with rapid antidepressant properties at subanaesthetic doses, thus providing a valuable research tool for the investigation of the neurobiology of major depressive disorder (MDD). This double-blind, randomized, placebo-controlled 1H-MRS study in 13 healthy subjects reveals the neuropharmacological effects of a single intravenous subanaesthetic ketamine infusion on prefrontal aspartate, glutamine and GABA levels in the 3-4 hour post-infusion interval. Our findings are in line with a shift in the excitatory-inhibitory balance following ketamine administration that may play an important role in restoring parts of the disrupted neurometabolic homeostasis in MDD patients.