title: Ameliorating treatment-refractory depression with intranasal ketamine: potential NMDA receptor actions in the pain circuitry representing mental anguish.
abstract: This article reviews the antidepressant actions of ketamine, an N-methyl-D-aspartame glutamate receptor (NMDAR) antagonist, and offers a potential neural mechanism for intranasal ketamine's ultra-rapid actions based on the key role of NMDAR in the nonhuman primate prefrontal cortex (PFC). Although intravenous ketamine infusions can lift mood within hours, the current review describes how intranasal ketamine administration can have ultra-rapid antidepressant effects, beginning within minutes (5-40 minutes) and lasting hours, but with repeated treatments needed for sustained antidepressant actions. Research in rodents suggests that increased synaptogenesis in PFC may contribute to the prolonged benefit of ketamine administration, beginning hours after administration. However, these data cannot explain the relief that occurs within minutes of intranasal ketamine delivery. We hypothesize that the ultra-rapid effects of intranasal administration in humans may be due to ketamine blocking the NMDAR circuits that generate the emotional representations of pain (eg, Brodmann Areas 24 and 25, insular cortex), cortical areas that can be overactive in depression and which sit above the nasal epithelium. In contrast, NMDAR blockade in the dorsolateral PFC following systemic administration of ketamine may contribute to cognitive deficits. This novel view may help to explain how intravenous ketamine can treat the symptoms of depression yet worsen the symptoms of schizophrenia.
authors.affiliation: 1Department of Psychiatry,Columbia University Medical Center,New York,New York,USA.
authors.forename: Lewis A
authors.initials: LA
authors.lastname: Opler
authors.affiliation: 1Department of Psychiatry,Columbia University Medical Center,New York,New York,USA.
authors.forename: Mark G A
authors.initials: MG
authors.lastname: Opler
authors.affiliation: 4Department of Neurobiology,Yale University School of Medicine,New Haven,Connecticut,USA.
authors.forename: Amy F T
authors.initials: AF
authors.lastname: Arnsten
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects; D061218:Depressive Disorder, Treatment-Resistant / Q000188:drug therapy* / Q000503:physiopathology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007649:Ketamine / Q000494:pharmacology / Q000627:therapeutic use*; D010146:Pain / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000187:drug effects / Q000503:physiopathology; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D013569:Synapses / Q000187:drug effects
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine
keywords: Antidepressant; area 25; glutamate; prefrontal cortex; rTMS