EFFECTS OF DORSOMEDIAL HYPOTHALAMUS ADMINISTRATION OF CRF AND CRF ANTAGONISTS TYPE 1 AND 2 ON THE BEHAVIOR OF ANIMALS SUBMITTED TO THE ELEVATED T-MAZE (ETM) MODEL OF ANXIETY

• Grant number: 12/16900-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2013
• End date: June 30, 2014
• Field of knowledge: Humanities - Psychology - Physiological Psychology
• Principal Investigator: Milena de Barros Viana
• Grantee: Bruno Aranha Pereira
• Host Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

During the last years, different brain regions have been related to the modulation of defensive responses of fear/anxiety. The dorsomedial hypothalamus is part of the medial hypothalamic region implicated with defense. Electrical or chemical stimulation of this structure evokes a series of behavioral and physiological responses similar to those present in a panic attack. Apart from neuroanatomical aspects, several neurotransmitter systems have also been implicated with the modulation of fear/anxiety-related responses. In this last respect, it has been shown that the systemic administration of corticotrophin releasing factor (CRF) exerts an anxiogenic effect in animal models of anxiety. CRF antagonists, on the other hand, exert anxiolytic effects. Few studies, however, have investigated the central effects of this class of drugs. The purpose of the present study is to investigate the effects of intra-dorsomedial hypothalamus administration of CRF and CRF antagonists on the behavior of animals submitted to the elevated T-maze (ETM) model of anxiety. The ETM measures two different behavioral responses: escape and avoidance. These behavioral responses have been respectively related, in terms of psychopathology, to panic and generalized anxiety disorder. In the present study, independent groups of animals (male Wistar rats) will be injected intra-dorsomedial hypothalamus with CRF, with the CRF type 1 antagonist antalarmine and with the CRF type 2 antagonist anti-sauvagine, and 10 min later they will be placed in the ETM for escape and avoidance measurements. For locomotor activity assessment, animals will be submitted to an open field.