ASSESMENT OF THE ROLE OF THE AMYDALOID COMPLEX, DORSAL HIPPOCAMPUS AND THE INFLUENCE OF GENDER AND AGE ON RESPONSES RELATED TO DEPRESSION IN MICE SUBMITTED TO THE STRESS OF WITNESSING SOCIAL DEFEAT

• Grant number: 23/01341-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2023
• End date: March 31, 2024
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Principal Investigator: Ricardo Luiz Nunes de Souza
• Grantee: Julian Humberto Avalo Zuluaga
• Host Institution: Faculdade de Ciências Farmacêuticas (FCFAR). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Human beings are exposed to different sources of stress. Currently, the most common form of stress comes from the social environment, whether experienced directly or through observation. Chronic exposure to stress is related to the development of psychiatric illnesses such as depression and anxiety, however, the effect of stress has been shown to be differential and dependent on variables such as gender and age. In addition, stress produces morpho functional changes in several areas of the brain, including the amygdaloid complex and dorsal hippocampus, limbic structures that has been shown to be related to emotional responses related to stress. Therefore, this study aims to (i) analyze the effect of witnessing stress to social defeat on depression-related responses in male and female mice (Swiss-Webster 21 days post-birth (DPN) and 58-60 DPN) evaluating the coat state, nest building, novel object exploration, weight gain and (ii) the pattern of neuronal activation in the amygdaloid complex and hippocampus. For this, two experiments will be carried out. In Experiment 1, we will assess the effects of stress on (a) behaviors related to depression (coat state, nest building, novel object exploration, weight gain) and (b) on the expression of ”FosB protein in the amygdala and dorsal hippocampus, using immunohistochemistry technique, in male and female mice exposed to witness social defeat stress at 58-60 DPN (em português estresse de testemunha da derrota social ou ETDS). A similar procedure will be conducted in Experiment 2, except that the late effect of early stress (applied at 21 days after birth) will be assessed on (c) depression-related behaviors (coat state, nest building, novel object exploration, weight gain) and (d) ”FosB protein expression in the amygdala and dorsal hippocampus, evaluated in male and female mice at 58-62 DPN.