Navegando por Autor "SAMPAIO, Gabriela Santos Alvarez"

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Sintomas não motores na doença de Parkinson: modelo de lesão intraestriatal por 6-OHDA em camundongos
(Universidade Federal do Pará, 2014-02-10) SAMPAIO, Gabriela Santos Alvarez; YAMADA, Elizabeth Sumi; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978
Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly, characterized by neurodegeneration of dopaminergic neurons of the substantia nigra (SN), with no clearly established etiology, though the causes may be associated with exposure to environmental toxins and genetic factors. The pathological processes involved in PD are mitochondrial dysfunction, oxidative stress, inflammation and excitotoxicity. The symptoms of PD are motor, cognitive and autonomic changes. However, few studies have analyzed the non-motor symptoms of PD, especially in animal models. In this context, the objective of this study was to assess non-motor symptoms of PD in animal models with lesions caused by the neurotoxin 6-hydroxydopamine with two different doses, injected bilaterally into the striatum. To achieve our goals we performed tests of open field, apomorphine, Morris water maze and olfactory discrimination tests, and histological analyzes. Our results showed motor abnormalities, learning and memory deficits associated with decreased dopaminergic cells in the SN, striatal neurons and neurons of the hippocampal CA1. Thus, this model for non-motor symptoms of PD can be used to understand the mechanisms involved in the disease, as well as to evaluate therapeutic strategies to slow or stop progression of PD.
Acesso aberto (Open Access)
Topografia de células ganglionares alfa na retina de roedores da Amazônia
(Universidade Federal do Pará, 2022-05) SAMPAIO, Gabriela Santos Alvarez; SOUZA, Givago da Silva; http://lattes.cnpq.br/5705421011644718; https://orcid.org/0000-0002-4525-3971
Introduction: The visual system of Amazonian rodents of the suborder Hystrichomorpha has been widely described, but little is known about the topography of alpha ganglion cells, which play a role in processing the vision of moving stimuli. Agouti (Dasyprocta aguti), paca (Cuniculus paca) and capybara (Hydrochoerus hydrochaeris) rodents are three different species of Hystrichomorpha that have a different circadian cycle and lifestyle. Objectives: To quantify alpha ganglion cell density and analyze cell body size according to eccentricity in the retina of agouti, paca and capybara. Methods: Three agouti, paca and capybara retinas from the pre-existing retinal collection at the Eduardo Oswaldo Cruz Laboratory of Neurophysiology at UFPA were used. Retinal collection were stained by the Nissl corpuscle staining method and direct counting was performed under a Zeiss optical microscope. The density of alpha-like ganglion cells was analyzed in different retinal eccentricities, such as in the visual range, area centralis, dorsal and ventral regions. Result: Analyzing the entire retina, the mean density of alpha-like ganglion cells in the agouti was 94.7±5.05 cells/μm2, in the paca it was 28.7±2.03 cells/μm2 and in the capybara it was 28.7±2.03 cells/μm2. of 101.03±24.42 cells/μm2. The presence of areas with high density of alpha ganglion cells was observed in the temporal region of the retina of the three rodents, and the agouti was the species that showed the most accentuated specialization of this type of ganglion cells. The cell body area of alpha ganglion cells that showed the highest frequency in the agouti retina was 200 μm², in the paca retina it was 300 to 600 μm² and in the capybara it was 300 to 500 μm². Conclusion: It is concluded that there is a relationship between ecology and density of alpha ganglion cells in the retina of large Brazilian rodents, so that those with diurnal habits have retinas with a greater number of these cells and with greater specialization in the temporal region.