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Effects of acute and chronic stress on behavioral defensive responses

Grant number: 11/17471-0
Support Opportunities:Regular Research Grants
Duration: November 01, 2011 - October 31, 2013
Field of knowledge:Humanities - Psychology - Physiological Psychology
Principal Investigator:Milena de Barros Viana
Grantee:Milena de Barros Viana
Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil
Associated researchers:Isabel Cristina Céspedes ; José Simões de Andrade ; Renata Oliveira Abrão


The concept of stress is based on the observation that any environmental change, either external or internal, can disturb the maintenance of homeostasis/allostasis, causing a series of physiological alterations, the so-called "general adaptation syndrome". The purpose of the stress reaction is to maintain homeostasis/allostasis, which includes physiological reactions such as endocrine activation (in particular of the hypothalamo-pituitary-adrenal - HPA axis) and visceral changes, which per se, do not produce pathological consequences. Nevertheless, when the stimulation is prolonged or sustained, exceeding the body's capacity to maintain homeostasis, stress can have pathological sequelae. The purpose of the present study is to investigate if and how an acute stressor (restriction) and a chronic stressor (chronic unpredictable mild stress, CUMS) alter behavior of animals tested in the elevated T-maze model of anxiety. Male Wistar rats will be submitted to an acute stressor (30 min of restriction) or to CUMS for 14 days and subsequentelly (1 h later for the acute stressor and 24 h later for CUMS) exposed to the elevated T-maze, for avoidance and escape measurements. In terms of psychopathology, these responses have been related to generalized anxiety and panic, respectively. Corticosterone levels will always be measured after stress exposure and behavioral measurements. Additionally, to investigate the effects of stress on motricity, animals will also be tested in an open field immediately after T-maze exposure. At last, the study will also investigate the effects of stress on brain structures implicated with defense through the use of immunohistochemical and molecular biology analysis (c-fos expression and in situ hybridization of CRF mRNA). (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
DE ANDRADE, J. S.; CESPEDES, I. C.; ABRAO, R. O.; DOS SANTOS, T. B.; DINIZ, L.; BRITTO, L. R. G.; SPADARI-BRATFISCH, R. C.; ORTOLANI, D.; MELO-THOMAS, L.; DA SILVAA, R. C. B.; et al. Chronic unpredictable mild stress alters an anxiety-related defensive response, Fos immunoreactivity and hippocampal adult neurogenesis. Behavioural Brain Research, v. 250, p. 81-90, . (11/17471-0, 11/01409-4)
SILVA, MARIANA S. C. F.; PEREIRA, BRUNO A.; CESPEDES, ISABEL C.; NASCIMENTO, JULIANA O. G.; BITTENCOURT, JACKSON C.; VIANA, MILENA B.. Dorsomedial hypothalamus CRF type 1 receptors selectively modulate inhibitory avoidance responses in the elevated T-maze. Behavioural Brain Research, v. 271, p. 249-257, . (11/17471-0, 13/17389-8)
DE ANDRADE, J. S.; ABRAO, R. O.; CESPEDES, I. C.; GARCIA, M. C.; NASCIMENTO, J. O. G.; SPADARI-BRATFISCH, R. C.; MELO, L. L.; DA SILVA, R. C. B.; VIANA, M. B.. Acute restraint differently alters defensive responses and fos immunoreactivity in the rat brain. Behavioural Brain Research, v. 232, n. 1, p. 20-29, . (11/17471-0)

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