Neuroethological study of the association between early life stress and depressive-like behaviors in Wistar rats

• Grant number: 15/10478-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2015
• End date: September 30, 2016
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Norberto Garcia Cairasco
• Grantee: João Pedro Guzzi Marques
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Chronic stress events, mainly in early life, are risk factors for developing Major Depression. Depressive disorders will affect, at any moment in life, 10% of Brazil's population, constituting one of the most causes that drive to disability and premature death. Decades of basic and clinic research found there is a straight relationship between the disjunction of Hipotalamus-Hipophysis-Adrenal axis' hormone dynamics and the Major Depression. Animal models are essential research tools that enable the study of antidepressant drugs and contribute to understanding the neuropathology underlying depressive disorders. There is still large drug resistance considering the currently available treatments and one of the methods widely used on the antidepressant pre-clinical screening tests is the Forced Swimming Test (FST). This test was developed by Porsolt in the '70s and it's used to evaluate the depressive-like behaviors in rodents contemplating only the reduction of total immobility time. Afterward some studies added a few other behaviors, but a complete behavioral study hasn't been performed yet. Antidepressant screening models should merge behavior trials neuropathologically valid with studies about neuroanatomical subtracts. In this context, the scope of this project is to propose a neuroethological new approach to the FST, seeking a neuroanatomical correlation through the immunohistochemically c-Fos quantification of specific nuclei. It will be used as a multimodal Early Life Stress protocol through the period PN1-PN21 in Wistar rats as a way to study the chronic and perinatal stress effects on depressive-like behaviors and the activation of the different neural subtracts.