In two spring studies, the team found ketamine briefly acts on mu-opioid receptors in prefrontal somatostatin interneurons and built a three-drug mix from 44 receptor candidates.
In stressed mice, the cocktail matched ketamine's antidepressant-like effects without motor impairment, working-memory deficits or conditioned place preference, while a second study linked lasting benefits to BDNF, TrkB and mGluR5 signalling.
The findings suggest ketamine works in a rapid opioid-dependent phase followed by synaptic strengthening, and could speed clinical testing because the planned trial uses compounds already approved or with human safety data.
With so many novel antidepressant approaches emerging, which will reach patients first—and will they truly outperform ketamine?
Could the new three-drug cocktail finally bring rapid, safe antidepressant relief for the millions who don't respond to current treatments?
How might targeting somatostatin interneurons reshape our understanding—and future treatment—of depression and other brain disorders?
Unveiling Ketamine’s Two-Phase Antidepressant Mechanism and a Safer Three-Drug Cocktail for Rapid, Sustained Depression Relief
Overview
A 2026 study by Weill Cornell Medicine uncovered ketamine's two-phase antidepressant mechanism. First, ketamine rapidly activates mu-opioid receptors on specific inhibitory neurons in the prefrontal cortex, causing cortical disinhibition and a glutamate surge that leads to fast symptom relief. This glutamate surge then triggers BDNF release, activating TrkB receptors that interact with mGluR5 receptors to remodel synapses, producing sustained antidepressant effects lasting days to weeks. Building on this, researchers designed a three-drug cocktail that mimics these phases using a partial mu-opioid agonist, a serotonin receptor agonist, and an mGluR5 modulator, achieving rapid and lasting relief with fewer side effects. Clinical trials are set to begin in late 2026, incorporating PET imaging to track treatment response.