Regional Blood Flow Signatures of Opioidergic Modulation of Ketamine in Major Depressive Disorder: A Randomized Crossover Study.
The American journal of psychiatry June 1, 2026 Luke A Jelen, Owen O'Daly, Fernando O Zelaya et al. 2 citations
Ketamine increased blood flow in specific brain regions (subgenual, pregenual, and dorsal anterior cingulate cortices) in adults with major depressive disorder, and this effect was not blocked by the opioid blocker naltrexone. However, naltrexone did disrupt the relationships between blood flow changes and both acute subjective effects and antidepressant response. The blood flow changes aligned with patterns of opioid and glutamate receptor distribution, suggesting that ketamine's effects involve interactions among multiple neurotransmitter systems.