Navegando por Orientadores "HERCULANO, Anderson Manoel"

Agora exibindo 1 - 2 de 2

Acesso aberto (Open Access)
Avaliação do efeito protetor da Euterpe oleracea (açaí) na resposta eletrofisiológica da retina de ratos expostos ao metilmercúrio
(Universidade Federal do Pará, 2013-03-19) COSTA, Alódia Brasil; ROCHA, Fernando Allan de Farias; http://lattes.cnpq.br/3882851981484245; HERCULANO, Anderson Manoel; http://lattes.cnpq.br/8407177208423247
Methylmercury (MeHg) is organic form most toxic of mercury. The MeHg exposure generates oxidative stress may affect the retina, because it has a high vulnerability due to their high content of polyunsaturated fatty acids and oxygen consumption. In this context, administration of exogenous antioxidants obtained from the diet, such as those present in Euterpe oleracea (açaí), could be a way to prevent this imbalance and its consequences. Therefore, the objective of this study was to evaluate the possible protective effect of Euterpe oleracea in electrophysiological changes caused by MeHg in the retina. For this was performed gavage with MeHgCl (5mg/kg) or saline (NaCl 0.9%) for 7 days and pretreatment with açaí (10%) per 28 days. Was used Wistar rats were divided into 4 groups: Group MeHg (received standard diet and MeHgCl); MeHg + Acai (enriched diet with acai and MeHgCl); Acai (enriched diet with açai and NaCl); Vehicle (standard diet and NaCl). One day after the last gavage animals were subjected to full-field electroretinography (ffERG) to obtain the scotopic responses (rods, mixed 1 and mixed 2) and photopic responses (cone and flicker at 12, 18, 24 and 30Hz). The next day to the ffERG was applied open field test to evaluate the animals locomotor activity. Subsequently, measurement of the lipid peroxidation by the method TBARS in retinal tissue. Statistical analysis was done by one-way ANOVA with Tukey post-test, considering significant p<0.05. The open field and body weight results showed no difference between groups. The MeHg reduced the amplitude of the following responses: b-wave in rod response (Vehicle: 114.6 ± 23.6 μV and MeHg: 41.2 ± 9.6 μV); a-wave (Vehicle: 8.4 μV and MeHg ± 1.4: 3.4 ± 0.3 μV) and b-wave (Vehicle: 176.7 ± 17.8 μV and MeHg: 69.5 ± 12.0 μV) in mixed 1 responses; a-wave (Vehicle: 103.1 ± 23.3 μV and MeHg: 40.2 ± 9.6 μV) and b-wave (Vehicle: 281 ±, 38.3 μV and MeHg: 138.6 ± 14μV) in mixed 2 response; a-wave (Vehicle: 27.2 ± 3.6 μV and MeHg: 7.5 ± 1.8 μV) and b-wave (Vehicle: 139.3 ± 16.1 μV and MeHg: 54.4 ± 10μV) of cones response; b-wave in frequencies 12 Hz (Vehicle: 67.7 ± 10μV and MeHg: 28.6 ± 6.9 μV), 18Hz (Vehicle: 31.3 ± 3.4 μV and MeHg : 14.2 ± 2.3 μV), 24Hz (Vehicle: 21.0 ± 1.8 μV and MeHg: 11.0 ± 1.1 μV) and 30Hz (Vehicle: 10.9 ± 0.6 μV and MeHg: 6.0 ± 1.1 μV). While the implicit time of the waves was not altered. The pretreatment with Euterpe oleracea prevented the decrease of amplitude of both waves in mixed 1 (a-wave: 8.3 ± 0.6 μV; b-wave: 144.1 ± 7,1 μV) and mixed 2 responses (a-wave: 106.4 ± 13.6 μV; b-wave: 275,2±27,6 μV), b-wave of cone response (104.5 ± 5.9 μV) and photopic flicker at 12 Hz (67.2 ± 9.1 μV), 18 Hz (29.5 ± 4.8 μV) and 24 Hz (21.9 ± 2.4 μV). Lipid peroxidation in retinal tissue of MeHg group (294.9 ± 205.8%) was higher than that of the Vehicle (100 ± 25.1%) and açaí protected against this oxidative damage (MeHg + Acai = 111.2 ± 26.1%). Our results demonstrate diffuse alteration in the electrophysiological response and increase in lipid peroxidation of the retina induced by MeHg and protection exerted by Euterpe oleracea in these two parameters. Thus, Euterpe oleracea could be used as an important alternative to attenuate the changes in the retina caused by MeHg.
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.