Modulatory action of environmental enrichment on hormonal and behavioral responses induced by chronic stress in rats: Hypothalamic renin-angiotensin system components

Author(s)

Costa, Rafaela ^[1] ; Carvalho, Maeline Santos Morais ^[1] ; Brandao, Juliana Dineia Perez ^[2] ; Moreira, Roseli Peres ^[2] ; Cunha, Tatiana Sousa ^[3] ; Casarini, Dulce Elena ^[2] ; Marcondes, Fernanda Klein ^[1]

Affiliation

^[1] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Biosci, Lab Stress, Piracicaba, SP - Brazil

^[2] Univ Fed Sao Paulo, Dept Med, Nephrol Div, Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Paulo, Sci & Technol Inst, Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: Behavioural Brain Research; v. 397, JAN 15 2021.
• Web of Science Citations: 0

Abstract

Environmental enrichment (EE) has been studied as a protocol that can improve brain plasticity and may protect against negative insults such as chronic stress. The aim of this study was to evaluate the effects of EE on the hormonal and behavioral responses induced by chronic mild unpredictable stress (CMS) in rats, considering the involvement of the renin-angiotensin system. Male adult rats were divided into 4 groups: control, CMS, EE, and CMS + EE, and the experimental protocol lasted for 7 weeks. EE was performed during 7 weeks, 5 days per week, 2 h per day. CMS was applied during weeks 3, 4, and 5. After the CMS (week 6), depression-like behavior was evaluated by forced swimming and sucrose consumption tests, anxiety level was evaluated using the elevated plus-maze test, and memory was evaluated using the Y-maze test. On week 7, the animals were euthanized and basal plasma levels of corticosterone and catecholamines were determined. The hypothalamus was isolated and tissue levels of angiotensin peptides were evaluated. CMS increased plasma corticosterone, norepinephrine, and epinephrine basal concentrations, induced depression-like behaviors, impaired memory, and increased hypothalamic angiotensin I, II, and IV concentrations. EE decreased stress hormones secretion, depression-like behaviors, memory impairment, and hypothalamic angiotensin II induced by stress. Reductions of anxiety-like behavior and norepinephrine secretion were observed in both stressed and unstressed groups. The results indicated that EE seemed to protect adult rats against hormonal and behavioral CMS effects, and that the reduction of angiotensin II could contribute to these effects. (AU)

• FAPESP's process: 10/51904-9 - Renin angiotensin and kallikrein kinin systems in hypertension, obesity, diabetes, desnutrition and sepsis: molecular, cellular and physiopathologic mechanisms
• Grantee: Dulce Elena Casarini
• Support Opportunities: Research Projects - Thematic Grants