Chemical Structure of Metabolite (IMAGE) NIH/National Institute of Mental Health Caption A team of NIH intramural scientists and grantees traced ketamine's rapid antidepressant effects to activation of AMPA receptors by a byproduct of its chemical breakdown called (2R,6R)-HNK - a different mechanism than had been previously assumed. Credit NIH - National Center for Advancing Translational Sciences Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.