Molecular mechanisms underlying the antidepressant actions of arketamine: beyond the NMDA receptor
Molecular Psychiatry May 7, 2021 Wei Yan, Lijia Chang, Kenji Hashimoto 242 citations
The antidepressant effects of the drug (R,S)-ketamine, a mixture of (R)-ketamine (arketamine) and (S)-ketamine (esketamine), are not primarily due to blocking the N-methyl-D-aspartate receptor (NMDAR), despite initial assumptions. Preclinical studies in rodents show arketamine has more potent and longer-lasting antidepressant-like effects than esketamine, even though arketamine binds less strongly to NMDAR. Clinical trials with other NMDAR-blocking compounds failed to produce robust antidepressant effects in humans, indicating rodent findings do not always translate. The exact molecular mechanisms remain unclear. This review covers recent findings on these mechanisms, the possible roles of the brain-gut-microbiota and brain-spleen axes, and arketamine's potential for treating cognitive impairment, Parkinson's disease, osteoporosis, inflammatory bowel diseases, and stroke.