Navegando por Assunto "Serotonina"

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Acesso aberto (Open Access)
Efeitos do tratamento subcrônico com fluoxetina sobre os comportamentos e parâmetros oxidativos de ratos submetidos ao exercício físico exaustivo
(Universidade Federal do Pará, 2017-08-25) LEAL, Jerusa de Carvalho; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Fluoxetine is an antidepressant drug of the selective serotonin reuptake inhibitor class, its use may be a therapeutic alternative in reversing or reducing the changes caused by low serotonergic activity. The increase in serotonergic levels can also be induced by regular physical exercise, in that sense, the health benefits and the prevention of diseases that this type of exercise are promoted are already well reported. However, when exercise is practiced exhaustively it may induce increased oxidative stress and changes in emotional behavior in humans and experimental animals. Therefore, the objective of this study was to evaluate the effects of subchronic treatment with fluoxetine on the behavior and oxidative parameters in rats submitted to exhaustive physical exercise in forced swimming. Therefore, adult male rats of Wistar strain were divided into sedentary animals and exposed to exhaustive exercise subcronically that were treated with fluoxetine 10 mg / kg / day (NaCl 0.9%) and saline either via i.p. for 7 days. After 30 minutes of intoxication the animals were individually exposed to exhaustive physical exercise for 20 minutes. On the eighth day of the experiment, the open field test (TCA) and the high cross labyrinth (LCE) were performed to evaluate spontaneous locomotion and anxiety - like behavior, respectively. The animals were then authanized and blood, liver and brain were collected for determination of GSH, TEAC, NO, and MDA levels. The results obtained, the animals treated with fluoxetine associated to exhaustive physical exercise showed reduction in the locomotion caused by the emotional stress in the ACT and reduction in the behavior similar to the anxiety in the LCE. Regarding the parameters of oxidative stress, fluoxetine associated with the practice of exhaustive physical exercise, in general, induced oxidative stress in the organism, mainly in the blood and liver of these animals, with reduction of the levels of GSH and TEAC and increase of levels of NO and MDA. On the other hand, in the brain, treatment with fluoxetine showed protective effect on oxidative stress, with reduction in NO and MDA levels and increase in antioxidant factors. On the data, it is concluded that fluoxetine associated with exhaustive exercise has dual effect of activity in relation to neurobehavioral and oxidative balance, reducing movement and increasing the anxiolytic effect, demonstrating antioxidant or pro-oxidant depending on the tissue or organ evaluated.
Acesso aberto (Open Access)
Papel da serotonina no comportamento defensivo do paulistinha (Danio rerio Hamilton 1822) adulto: Diferenças entre modelos comportamentais, linhagens, e efeitos do estresse predatório agudo
(Universidade Federal do Pará, 2014-11-14) OLIVEIRA, Caio Maximino de; HERCULANO, Anderson Manoel
Anxiety disorders present the highest incidence in the world population among psychiatric disorders, and the clinical efficacy of anxiolytic drugs is low, partially due to lack of knowledge on the neurochemical bases of these disorders. To reach a more ample and evolutionarily grounded comprehension of these phenomena, the use of phylogenetically older species can be an interesting approach in the field of behavioral modeling; thus, we suggest the use of zebrafish (Danio rerio Hamilton 1822) in the attempt to understand the modulation of these behaviors by the serotonergic system. We demonstrate that extracellular serotonin levels in the brains of adult zebrafish exposed to the light/dark preference test [LDT] (but not to the novel tank test [NTT]) are increased in relation to animals which are handled, but not exposed to the apparatuses. Moreover, serotonin tissue levels levels in the hindbrain and forebrain are elevated by the exposure to the LDT, while tissue levels in the midbrain are elevated by exposure to the NTT. Extracellular serotonin levels correlate positively with scototaxis, thigmotaxis and risk assessment in the LDT and negatively with geotaxis in the NTT. Acute treatment with a low dose of fluoxetine (2.5 mg/kg) increases scototaxis, thigmotaxis, and risk assessment in the LDT, and decreases geotaxis and freezing and facilitates habituation in the NTT. Treatment with buspirone decreases scototaxis, thigmotaxis and freezing at 25 and 50 mg/kg in the LDT and decreases risk assessment at 50 mg/kg; in the NTT, both doses decrease geotaxis, while the highest dose decreases freezing and facilitates habituation. Treatment with WAY 100635 decreases scototaxis at 0.003 and 0.03 mg/kg, while only the highest dose decreases thigmotaxis and risk assessment in the LDT. In the NTT, both doses decrease geotaxis, while only the lower dose facilitates habituation and increases homebase time. Treatment with SB 224289 did not alter scototaxis, but increased risk assessment at 2.5 mg/kg; in the NTT, this drug decreased geotaxis and decreased erratic swimming at 2.5 and 5 mg/kg, while at 2.5 mg/kg it increased homebase time. Treatment with DL-para-clorophenylalanine (2 x 300 mg/kg injections, separated by 24 h) decreased scototaxis, thigmotaxis and risk assessment in the LDT, and increased geotaxis and homebase time and decreased habituation in the NTT. When animals were pre-exposed to a conspecific “alarm substance”, extracellular serotonin levels were raised in association with an increase in scototaxis, freezing and erratic swimming in the LDT; both behavioral and neurochemical effects were blocked by pre-treatment with fluoxetine (2,5 mg/kg), but not with WAY 100,635 (0,003 mg/kg). Animals from the leopard strain show increased scototaxis and risk assessment in the LDT, as well as increased 5-HT tissue levels in the encephalon; the behavioral phenotype is rescued by treatment with fluoxetine (5 mg/kg). These data suggest that the serotonergic system of zebrafish modulates behavior in the LDT and NTT in opposite ways; that the fright response produced by alarm substance seems to increase serotonergic activity, an effect which is possibly mediated by serotonin transporters; and that at least one high-anxiety mutant phenotype is associated with serotonin uptake. It is thus suggested that from a functional point of view serotonin increases anxiety and decreases fear in zebrafish.