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Repeated social stress reveals two populations characterized by different behavioral and endocrine stress response profiles: a model of stress vulnerability and resilience
Author(s) -
Wood Susan K,
Walker Hayley,
Valentino Rita J,
Bhatnagar Seema
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.591.2
Subject(s) - social defeat , habituation , chronic stress , phenotype , medicine , endocrinology , psychology , social stress , behavioural despair test , population , endocrine system , adrenocorticotropic hormone , neuroscience , biology , hormone , hippocampus , gene , biochemistry , environmental health , antidepressant
Chronic exposure to social stress results in psychological disorders in vulnerable individuals. Repeated social stress (7 days) using a rat resident‐intruder model resulted in two populations, characterized by distinct behavioral and endocrine profiles. One population exhibited a passive response (e.g., freezing) and assumed a defeat posture within a short latency (SL). The second group exhibited proactive behaviors (e.g., boxing) and a longer latency (LL) to be defeated. The proactive behavior of the LL phenotype emerged after 4 sessions of stress and was temporally correlated with habituation of the adrenocorticotropin (ACTH) response to defeat, not observed in SL rats until day 7. The SL phenotype exhibited a stress axis dysfunction resembling melancholic depression, characterized by adrenal hypertrophy, blunted ACTH release to CRF and novel restraint stress, and decreased CRF 1 receptors in pituitary compared with controls. SL rats also exhibited depressive‐like behaviors in the forced swim test. In contrast, the LL phenotype exhibited a blunted ACTH response to a CRF infusion; however the ACTH response to restraint was facilitated. These data suggest the LL phenotype is more resilient to adverse consequences of social stress. Elucidating the neural basis of these two phenotypes may increase our understanding of the pathophysiology of stress‐related depression. MH06751 to SB, MH40008, MH58250.