Repeated unpredictable stress and social isolation induce chronic HPA axis dysfunction and persistent abnormal fear memory

Copyright © 2020 Elsevier Inc. All rights reserved..

The lack of progress in the psychopharmacological treatment of stress-related disorders such as PTSD is an ongoing crisis due to its negative socioeconomic implications. Current PTSD pharmacotherapy relies on a few FDA approved medications used primarily for depression which offer only symptomatic relief and show limited efficacy. As the population of PTSD patients is growing, the identification of effective etiology-based treatments for the condition is a high priority. This requires an in-depth understanding of the neurobiological and behavioral outcomes of stress in translationally relevant animal models. In this study, we use neuroendocrine, biochemical and behavioral measures to assess the HPA axis function and fear-memory deficits in a mouse model of chronic stress. The chronic stress procedures involved exposure to 21 days of repeated unpredictable stress (RUS), including predator stress, restraint and foot shock, followed by chronic social isolation. We show that mice exposed to our stress paradigm demonstrate exaggerated fear memory recall and blunted HPA axis functionality at one month after RUS. Our neuroendocrinal testing suggests that the attenuated stress response in our model may be related to an alteration in the adrenal MC2 receptor reactivity. While there was no noticeable change in pituitary negative feedback regulation mechanisms, CRH and phosphorylated Glucocorticoid receptors levels were altered in the hypothalamus. We also show that chronic supplementation with a peripheral glucocorticoid receptor agonist (low-dose dexamethasone) after RUS partially restores a number of stress-related behavioral deficits in the RUS model. This suggests a direct relationship between HPA axis function and behavior in our model. Our findings emphasize the importance of the adrenal receptors as a target for HPA axis dysfunction in stress and fear-related disorders.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:104

Enthalten in:

Progress in neuro-psychopharmacology & biological psychiatry - 104(2021) vom: 10. Jan., Seite 110035

Sprache:

Englisch

Beteiligte Personen:

Algamal, Moustafa [VerfasserIn]
Pearson, Andrew J [VerfasserIn]
Hahn-Townsend, Coral [VerfasserIn]
Burca, Ioana [VerfasserIn]
Mullan, Michael [VerfasserIn]
Crawford, Fiona [VerfasserIn]
Ojo, Joseph O [VerfasserIn]

Links:

Volltext

Themen:

7S5I7G3JQL
Adrenal glands
Anti-Inflammatory Agents
Chronic variable stress
Corticosterone
Dexamethasone
Fear memory
HPA axis
Journal Article
PTSD
Research Support, Non-U.S. Gov't
Social isolation
W980KJ009P

Anmerkungen:

Date Completed 29.11.2021

Date Revised 29.11.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.pnpbp.2020.110035

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM312591918