Departament de Patologia i Terapèutica Experimental, Institut de Neurociències, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain. jbonaventura@ub.edu.
2 papers in the library · 63 citations · publishing 2025
Ketamine, a racemic compound used as an anesthetic, analgesic, and recreational drug, is being investigated for treating refractory depression and comorbid conditions like anxiety, obsessive-compulsive disorder, and opioid use disorder. Although ketamine is traditionally classified as an NMDA receptor antagonist, this review argues its pharmacology should be redefined to include opioid receptors and the endogenous opioid system. The authors propose that ketamine's antidepressant effects may arise from bifunctional, synergistic interactions involving both NMDA and opioid receptors.
Esketamine, a new antidepressant, works through a complex interaction with brain chemicals rather than a single target. In mice, esketamine increased movement and raised overall dopamine levels by slowing dopamine removal, not by boosting its release. It also reduced glutamate activity. However, it decreased spontaneous dopamine release events and blunted reward-triggered dopamine release, which lowered the mice's motivation to work for rewards. Some of these dopamine effects were partially blocked by naloxone, an opioid blocker, and depended on glutamate input. The findings suggest esketamine's effects on brain chemistry vary by brain circuit and behavioral state.