Análise comportamental e eletrofisiológica do uso de glicocorticoides no sistema nervoso central em modelos animais de depressão

Abstract

Dexamethasone is a glucocorticoid widely prescribed in Medicine, used as immunosuppressant and anti-inflammatory as well as fluoxetine, which is an antidepressant, serotonin reuptake, which can be used at some point while aiming their respective purposes. The aim of this study was to evaluate the electroencephalographic abnormalities in animals administered with these drugs as well as the behavioral effects evaluated in an animal model of depression, forced swimming. The study was conducted in adult male Wistar rats subjected to administration of dexamethasone acute dose of 4 mg/kg, 24 hours before electrocorticographic record, and chronic, administered for seven days every 24 hours at a dose of 4 mg/kg i.p. Fluoxetine was administered at a dose of 5 mg/kg, for seven days orally with a similar tool the orogastric tube, gavage procedure. After administration, the electroencephalographic parameters of drug activity were recorded and analyzed. When comparing the acute administration of dexamethasone with chronic, there were no statistical differences, but there was a trend towards decreased Theta and Gamma force for chronic use. The group, who received fluoxetine averaged amplitude of 2,661 ± 0,5850 mV²/Hz x 10-3, proving fluoxetine efficacy in controlling depression caused by forced swimming. For the group received dexamethasone chronically and fluoxetine to reverse the power of the middle frame was 0.4758 ± 0.2514 mV²/Hz x 10-3, as there is no statistical difference between the dexamethasone group and dexamethasone fluoxetine, fluoxetine failed to reverse depressive symptoms caused by dexamethasone. In the forced swimming, the fluoxetine group had decreased fluctuation time, mean time of 45.33 ± 23.26 seconds, demonstrating that the group was not depressed. In the group administered with dexamethasone chronic form and assessed the possibility of reversing depressive disorder with fluoxetine immobility time average was 169.8 ± 24.5 seconds indicating that fluoxetine had no effect on the depression caused by chronic application of dexamethasone. We conclude from this study that the glucocorticoid cause changes in electrocorticogram and depression in the forced swimming test (FST). Fluoxetine got no effect on the rats subjected to the FST, after the use of dexamethasone.