In adult male rats exposed to repeated corticosterone (a model of depression), ketamine restored the expression of reelin, a protein implicated in depression, and both reelin and ketamine rescued synaptic levels of mTOR and its activated form p-mTOR in the hippocampus and cerebellum, which had been reduced by corticosterone. Reelin, but not ketamine, also normalized serotonin transporter clustering on peripheral lymphocytes. These results suggest ketamine modulates reelin expression and support exploring reelin itself as a potential fast-acting antidepressant.
Chronic stress reduces reelin, a brain protein, in the hippocampus and causes depression-like behavior. A single dose of reelin or ketamine each reversed these behavioral and molecular effects within one hour, and the benefit lasted at least one week. When given together, reelin and ketamine showed additive effects after one week. The findings suggest that reelin-based treatments could become a new class of rapid-acting antidepressants.
In neurons derived from induced pluripotent stem cells of five women with treatment-resistant depression (average age 40.2 years), both the glycoprotein reelin and the ketamine metabolite (2R,6R)-hydroxynorketamine increased expression of several synaptic proteins (GluA1, PSD-95, Dab1, Synapsin I, and p-ERK) within one hour, with effects declining by 24 hours. Gene expression changes were similar for both compounds, though only reelin upregulated mTORC1 signaling. The findings suggest that iPSC-derived neurons may serve as a useful in vitro model for studying treatment-resistant depression and testing potential therapeutics.