Risk assessment behaviors associated with corticosterone trigger the defense reaction to social isolation in rats: Role of the anterior cingulate cortex

Author(s)

Reis, Fernando M. C. V. ^{[1, 2]} ; Albrechet-Souza, Lucas ^{[1, 2]} ; Franci, Celso R. ^[3] ; Brandao, Marcus L. ^{[1, 2]}

Affiliation

^[1] Inst Neurociencias & Comportamento INeC, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Lab Psicobiol, BR-14049 Ribeirao Preto - Brazil

^[3] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Fisiol, BR-14049 Ribeirao Preto - Brazil

• Document type: Journal article
• Source: STRESS-THE INTERNATIONAL JOURNAL ON THE BIOLOGY OF STRESS; v. 15, n. 3, p. 318-328, MAY 2012.
• Web of Science Citations: 11

Abstract

The extent to which the hypothalamic-pituitary-adrenal axis is activated by short-term and long-term consequences of stress is still open to investigation. This study aimed to determine (i) the correlation between plasma corticosterone and exploratory behavior exhibited by rats subjected to the elevated plus maze (EPM) following different periods of social isolation, (ii) the effects of the corticosterone synthesis blocker, metyrapone, on the behavioral consequences of isolation, and (iii) whether corticosterone produces its effects through an action on the anterior cingulate cortex, area 1 (Cg1). Rats were subjected to 30-min, 2-h, 24-h, or 7-day isolation periods before EPM exposure and plasma corticosterone assessments. Isolation for longer periods of time produced greater anxiogenic-like effects on the EPM. However, stretched attend posture (SAP) and plasma corticosterone concentrations were increased significantly after 30 min of isolation. Among all of the behavioral categories measured in the EPM, only SAP positively correlated with plasma corticosterone. Metyrapone injected prior to the 24 h isolation period reversed the anxiogenic effects of isolation. Moreover, corticosterone injected into the Cg1 produced a selective increase in SAP. These findings indicate that risk assessment behavior induced by the action of corticosterone on Cg1 neurons initiates a cascade of defensive responses during exposure to stressors. (AU)

• FAPESP's process: 11/00041-3 - Neurobiology of stress: the sensorimotor gating
• Grantee: Marcus Lira Brandão
• Support Opportunities: Research Projects - Thematic Grants