ArticleBiological psychiatry2022
Contribution of the Opioid System to the Antidepressant Effects of Fluoxetine.
Article in Biological psychiatry, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
6 citing papers in PubMed, 16 citations in OpenAlex.
- AiScience · 2026Article
- Hippocampal SGK1 promotes vulnerability to depression: the role of early life adversity, stress, and genetic risk.Molecular psychiatry · 2025Article
- Antidepressants and the endogenous opioid system.Biochemical pharmacology · 2025Review
- Opioid Mechanisms and the Treatment of Depression.Current topics in behavioral neurosciences · 2024Review
- Down the membrane hole: Ion channels in protozoan parasites.PLoS pathogens · 2022Review
- Integrative multi-omics landscape of fluoxetine action across 27 brain regions reveals global increase in energy metabolism and region-specific chromatin remodelling.Molecular psychiatry · 2022Article
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Authors and funding
19 authors at 6 institutions in 3 countries.
Funding
Abstract
backgroundSelective serotonin reuptake inhibitors such as fluoxetine have a limited treatment efficacy. The mechanism by which some patients respond to fluoxetine while others do not remains poorly understood, limiting treatment effectiveness. We have found the opioid system to be involved in the responsiveness to fluoxetine treatment in a mouse model for anxiety- and depressive-like behavior.
methodsWe analyzed gene expression changes in the dentate gyrus of mice chronically treated with corticosterone and fluoxetine. After identifying a subset of genes of interest, we studied their expression patterns in relation to treatment responsiveness. We further characterized their expression through in situ hybridization and the analysis of a single-cell RNA sequencing dataset. Finally, we behaviorally tested mu and delta opioid receptor knockout mice in the novelty suppressed feeding test and the forced swim test after chronic corticosterone and fluoxetine treatment.
resultsChronic fluoxetine treatment upregulates proenkephalin expression in the dentate gyrus, and this upregulation is associated with treatment responsiveness. The expression of several of the most significantly upregulated genes, including proenkephalin, is localized to an anatomically and transcriptionally specialized subgroup of mature granule cells in the dentate gyrus. We have also found that the delta opioid receptor contributes to some, but not all, of the behavioral effects of fluoxetine.
conclusionsThese data indicate that the opioid system is involved in the antidepressant effects of fluoxetine, and this effect may be mediated through the upregulation of proenkephalin in a subpopulation of mature granule cells.
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