O papel da galalina na modulação da ansiedade experimental mediada pela matéria cinzenta periaquetutal dorsal (MCPD) de ratos

• Autor(a) principal: Soares, Flávia Roberta Chaves
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/1975
• topic: Galanina; Matéria cinzenta periaquedutal dorsal; Labirinto em T elevado; Farmacologia Bioquímica e Molecular; Psicofarmacologia; Ansiedade; Ouvidos; 61

Galanin (GAL) is a 29 amino acids peptide that is present in the CNS of many mammals, including human being. The distribution of GAL and its receptors in emotions control structures involved suggests a possible modulatory role of this neuropeptide on anxiety. The dorsal periaqueductal gray (DPAG) is considered a key structure for behavioral and autonomic expression of defensive behavior. However, the role of GAL in this region has not been studied. The DPAG receives galaninergic projections from other structures, but does not synthesize the peptide on their cell bodies. GAL's actions are mediated by 3 metabotropic receptors, GALR1 and GALR3, which increase K+ efflux, and GALR2, which increases Ca2+ intracellular concentration. Using in situ hybridization technique was described the presence of GALR1 and GalR2 receptors in rat DPAG neurons, but there is GALR1 in greater density. The aim of this study was to investigate the involvement of GAL on the modulation of experimental anxiety by DPAG in rats. Therefore, Wistar rats with a unilateral cannula aimed at the DPAG (AP-lambda: 0 mm; L: 2.0 mm; e P: 4.0 mm, 15o), where the drugs were administered, received the following drugs: GAL (0.1; 0.3; 1.0 e 3.0 nmol/ 0.2μL), M617 – selective agonist GALR1 (0.3; 1.0 e 3.0 nmol/ 0.2μL) e AR-M1896 – selective agonist GALR2 (0.3; 1.0 e 3.0 nmol/ 0.2μL). After 5-7 days of recovery, each animal received an injection of drug and tests were carried-out in the plus-maze, elevated T-maze (ETM) or Vogel Test 20 min later. Each experiment was conducted with separated groups of animals (n=5-12). Tests performed at plus-maze after injection of GAL or selective agonists M617 and AR-M1896 into-DPAG did not change percentage of entries and percentage of time spent in the open arms. The analysis showed that treatment with GAL (3 nmol) significantly impaired Avoidance 2 in the ETM, without change Escape behavior. Acute treatment with GAL did not change locomotion in the Open Field. Finally, GAL (1.0 e 3.0 nmol) did not show difference in the number of punished licks at Conflict Vogel Test in comparison with control group. Thus, the anxiolytic effect of GAL in the DPAG seems to depend on the experimental model of anxiety employee and anxiety level generated by them. Key-words: Galanin. DPAG. Anxiety. T-maze.