Molecular psychiatryMar 4, 2026

Changes in AMPA receptors may explain ketamine's effectiveness in hard-to-treat depression

Psychedelic Science Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jun 28, 2026

Abstract

Essence

In treatment-resistant depression, ketamine's antidepressant effect was linked to changes in brain AMPA receptor density.

Evidence

This human PET imaging analysis using the AMPAR tracer [C]K-2 found lower AMPAR density with greater illness severity, altered AMPAR distribution in TRD versus healthy participants, and ketamine-related AMPAR density changes that correlated with antidepressant response.

Caveat

The study is an imaging correlation analysis in patients, so it links AMPAR dynamics to ketamine response without proving causation.

Simplified

Approximately 30% of patients with depression suffer from treatment-resistant depression (TRD). Ketamine has shown antidepressant efficacy for TRD. While glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) has been demonstrated to play crucial roles in the process of pharmacological action of ketamine in experimental animals, it remains elusive how ketamine exhibits its efficacy through changes in AMPAR dynamics in patients with TRD. In this study, using a positron emission tomography (PET) tracer, [C]K-2, which depicts AMPAR density in the living human brain, we detected a negative correlation between AMPAR density and illness severity and differences in AMPAR distribution between patients with TRD and healthy participants. Furthermore, we detected brain areas where ketamine administration altered AMPAR density in significant correlations with ketamine-induced antidepressant effect in patients with TRD. AMPAR density alteration in these regions partially rescued AMPAR phenotype in the affected areas. Thus, AMPAR dynamics underlies the antidepressant effect of ketamine in patients with TRD. 11