Corticotropin-Releasing Factor Receptors in the Locus Coeruleus Modulate the Enhancement of Active Coping Behaviors Induced by Chronic Predator Odor Inoculation in Mice.

Qiong Wang,Weiwen Wang,Jianxu Zhang,Yingjuan Liu

doi:10.3389/fpsyg.2019.03028

Abstract

Stress inoculation has been proved to induce active coping behaviors to subsequent stress. However, the specific neural mechanisms underlying this effect remain unclear. In this study, a chronic and mild predator odor exposure model was established to investigate the effect of predator odor stress inoculation on behaviors in novel predator odor exposure, open field test and forced swimming test (FST), and on the expression of CRF receptors in locus coeruleus (LC) and dorsal raphe nuclei (DRN). The results showed that predator odor stress inoculation increased the active coping of mice under the severe stress environment without changing the stress response to a new predator odor. Meanwhile, in LC, the CRFR1 expression was increased by predator odor stress inoculation. These results suggested that predator odor stress inoculation can be used as an effective training method to improve active response to later severe stress and the function of CRFR1 in LC might be a potential underlying biological mechanism.

Highlights

Stress is a generalized set of physiological and psychological responses observed when an organism is placed under challenging circumstances (Greenberg et al, 2013; Wang et al, 2018)
Some human studies have found that stress experience in childhood and adolescent can effectively improve the ability to cope with similar stressors in adulthood (Khoshaba and Maddi, 1999; Mortimer and Staff, 2004; Forest et al, 2010; Bosnjak et al, 2019; Navaee and Kaykha, 2019). These findings suggest that stress inoculation training may be a good method to enhance the adaptive response to stress, which is of great significance for the prevention and treatment of stress-related mental diseases
In order to verify the effect of predator odor stress inoculation and explore its potential neurobiological mechanism, the current study examined the effects of predator odor exposure both on the behaviors and corticotropin-releasing factor (CRF) receptor expression in dorsal raphe nuclei (DRN) and locus coeruleus (LC)

Summary

Introduction

Stress is a generalized set of physiological and psychological responses observed when an organism is placed under challenging circumstances (Greenberg et al, 2013; Wang et al, 2018). The adaptive and maladaptive responses to stressor are closely related to psychological health, and the intensity and duration of stress are important factors affecting the risk of mental disorders. Predator stress is a kind of instinctive response for maintaining the reproduction and survival of species (Philbert et al, 2015; St-Cyr and McGowan, 2015). The excessive predator stress has been documented to exert negative effects on behavior, emotion and cognition in the pattern of stress maladaptation (Apfelbach et al, 2005). Mild predator stress can lead to active coping behaviors in response to stress

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