Effects of chronic mild unpredictable stress on behavioral responses measured in the elevated T-maze

• Grant number: 11/17683-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2011
• End date: June 30, 2013
• Field of knowledge: Humanities - Psychology - Physiological Psychology
• Principal Investigator: Milena de Barros Viana
• Grantee: Renata Oliveira Abrão
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

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 exposition to a chronic stressor (chronic unpredictable mild stress, CUMS) alters behavior of animals tested in the elevated T-maze model of anxiety. Male Wistar rats will be submitted to CUMS for 14 days and on the 15th day 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. To investigate the effects of stress on motricity, animals will also be tested in an open field immediately after T-maze exposure. The study will also be complemented by immunohistochemical analysis (c-fos) to verify the effects of stress on the activation of brain structures related to fear/anxiety. (AU)