Fri. Oct 11, 2019 10:30 AM - 12:10 PM Room 14 (Palace Room A)

Organizer / Chair: Tung-Ping T SU (Department of Psychiatry, Cheng-Hsin General Hospital, Taipei, National Yang-Ming University, Taiwan), Co-chair: ‌Hisashi MORI (Department of Molecular Neurosciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan), Discussant: ‌Nagahide TAKAHASHI (Hamamatsu University School of Medicine, Japan)

The N-methyl-D-aspartate (NMDA) receptor antagonist ketamine exerts rapid and sustained antidepressant effects in depressed patients. Ketamine is a racemic mixture of equal amounts of enantiomers, (R)-ketamine and (S)-ketamine. The neural mechanisms that underlie different effects of these enantiomers remain unclear. Recent animal studies has demonstrated that (R)-ketamine has greater potency and longer-lasting antidepressant effects than (S)-ketamine. However, neural mechanisms that underlie different effects of these enantiomers still remain unclear. Further, GluN2D is a subunit of NMDA receptor, which plays an important role for the fast antidepressant effect of ketamine. The first study, presented by Dr. Ide to investigate the rapid and sustained antidepressant cognitive impairment effects of these enantiomers on the mice with and without GluN2D (wildtype) using TST and Novl Object Recognition Test (NORT) respectively. The second speaker Ago using chronic corticosterone –induced (CORT) mouse model depression confirms that (R)-ketamine exerts higher potency in antidepressant effects than (S)-ketamine, also do the metabolites (2R, 6R, Hydrooxynorketamine). He has tried to use the technique of microdialysis to analyze the concentration of neurotransmitters related to the different enantiomers in order to clarify the common and distinct neural mechanisms for antidepressant effects of ketamine and its enantiomers. Up to date, there has no clinical trial of (R)-ketamine in humans, the third speaker Chen conducted a double-blind, randomized ketamine vs. placebo study and tried to understand how the changes of brain connectivity using FcMRI technique to support the PFC-related circuit modulation associated with the rapid antidepressant effects of ketamine. The final speaker Su initiated a maintenance therapy for ketamine responder by a double blind, RCS, with D-cycloserine vs. placebo for 7 week study to see if the partial agonist of glycine site on NMDA receptor could continue to sustain the response of ketamine on treatment resistant depression.