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Papers of the Week

Papers: 22 Feb 2020 - 28 Feb 2020


Animal Studies, Pharmacology/Drug Development

2020 Feb 04

Proc Natl Acad Sci U S A



Opioid system is necessary but not sufficient for antidepressive actions of ketamine in rodents.


Klein ME, Chandra J, Sheriff S, Malinow R
Proc Natl Acad Sci U S A. 2020 Feb 04; 117(5):2656-2662.
PMID: 31941713.


Slow response to the standard treatment for depression increases suffering and risk of suicide. Ketamine, an -methyl-d-aspartate (NMDA) receptor antagonist, can rapidly alleviate depressive symptoms and reduce suicidality, possibly by decreasing hyperactivity in the lateral habenula (LHb) brain nucleus. Here we find that in a rat model of human depression, opioid antagonists abolish the ability of ketamine to reduce the depression-like behavioral and LHb hyperactive cellular phenotypes. However, activation of opiate receptors alone is not sufficient to produce ketamine-like effects, nor does ketamine mimic the hedonic effects of an opiate, indicating that the opioid system does not mediate the actions of ketamine but rather is permissive. Thus, ketamine does not act as an opiate but its effects require both NMDA and opiate receptor signaling, suggesting that interactions between these two neurotransmitter systems are necessary to achieve an antidepressant effect.