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Masella G, Silva F, Corti E, Azkona G, Madeira MF, Tomé ÂR, Ferreira SG, Cunha RA, Duarte CB, Santos M. The amygdala NT3-TrkC pathway underlies inter-individual differences in fear extinction and related synaptic plasticity. Mol Psychiatry 2024; 29:1322-1337. [PMID: 38233468 PMCID: PMC11189811 DOI: 10.1038/s41380-024-02412-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 01/19/2024]
Abstract
Fear-related pathologies are among the most prevalent psychiatric conditions, having inappropriate learned fear and resistance to extinction as cardinal features. Exposure therapy represents a promising therapeutic approach, the efficiency of which depends on inter-individual variation in fear extinction learning, which neurobiological basis is unknown. We characterized a model of extinction learning, whereby fear-conditioned mice were categorized as extinction (EXT)-success or EXT-failure, according to their inherent ability to extinguish fear. In the lateral amygdala, GluN2A-containing NMDAR are required for LTP and stabilization of fear memories, while GluN2B-containing NMDAR are required for LTD and fear extinction. EXT-success mice showed attenuated LTP, strong LTD and higher levels of synaptic GluN2B, while EXT-failure mice showed strong LTP, no LTD and higher levels of synaptic GluN2A. Neurotrophin 3 (NT3) infusion in the lateral amygdala was sufficient to rescue extinction deficits in EXT-failure mice. Mechanistically, activation of tropomyosin receptor kinase C (TrkC) with NT3 in EXT-failure slices attenuated lateral amygdala LTP, in a GluN2B-dependent manner. Conversely, blocking endogenous NT3-TrkC signaling with TrkC-Fc chimera in EXT-success slices strengthened lateral amygdala LTP. Our data support a key role for the NT3-TrkC system in inter-individual differences in fear extinction in rodents, through modulation of amygdalar NMDAR composition and synaptic plasticity.
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Affiliation(s)
- Gianluca Masella
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Francisca Silva
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Elisa Corti
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Garikoitz Azkona
- Department of Basic Psychological Processes and Their Development, School of Psychology, University of the Basque Country (UPV/EHU), San Sebastian, Spain
| | - Maria Francisca Madeira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Ângelo R Tomé
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Samira G Ferreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Mónica Santos
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
- Institute of Interdisciplinary Research, University of Coimbra (iiiUC), Coimbra, Portugal.
- Centre for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal.
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