Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2390

O Doutorado Acadêmico pertence ao Programa de Pós-Graduação em Neurociências e Biologia Celular (PPGNBC) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA).

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    Método baseado me cromatografia líquida de alta eficiência para analisar a atividade dos transportadores de GABA no sistema nervoso central
    (Universidade Federal do Pará, 2022-08) MORAES, Edinaldo Rogério da Silva; SILVA, Anderson Manoel Herculano Oliveira da; http://lattes.cnpq.br/8407177208423247
    The GATs are the membrane proteins responsible for the uptake of GABA in the central nervous system. Alterations in GAT activity are implicated in several neurological diseases, including retinopathies. The present study describes an alternative method to determine GAT activity in tissue preparations of the central nervous system, using high performance liquid chromatography (HPLC) with fluorescence detection. The GABA concentration in the medium was determined using the o-phthaldehyde (OPA)-derivation protocol validated by the Brazilian Health Regulatory Agency (ANVISA) and the United States Food and Drug Administration (US-FDA). The GAT activity in the retinal preparations was determined through the evaluation of the GABA uptake, which was measured by assessing the difference between the initial and final concentrations of GABA in the incubation médium (Δ𝐺𝑎𝑏𝑎 = [𝐺𝑎𝑏𝑎] 𝑡_0 − [𝐺𝑎𝑏𝑎] 𝑡_𝑒𝑛𝑑). The evaluation of the GAT kinetics returned values of Km = 382.5 ± 32.2 μM and Vmax = 34 nmol/mg of protein. The data also demonstrated that the GABA uptake was predominantly Na+ and temperature-dependent, and was also inhibited by incubation with nipecotic acid, a substrate of GABA transporters. Taken together, these findings confirm that our approach provided a specific measure of GAT activity in retinal tissue. The data presented here thus validate, for the first time, an alternative, simple and sensitive method for the evaluation of GAT activity using high performance chromatography on preparations of the central nervous system.
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    Semelhanças cognitivas inesperadas entre idosos e jovens: variabilidade e desempenho cognitivo
    (Universidade Federal do Pará, 2023-08) JARDIM, Naina Yuki Vieira; TORRES, Natáli Valim Oliver Bento; http://lattes.cnpq.br/1927198788019996; https://orcid.org/0000-0003-0978-211X; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
    Interindividual variability in cognitive performances has been investigated as they may provide important clues about the multivariate age-related cognitive decline. In the present work, we searched for cognitive variability, similarities, and differences between older and young people. For this, we used hierarchical cluster and canonical discriminant function analysis of cognitive scores using specific and sensitive tasks from the Cambridge Neuropsychology Test Automated Battery - CANTAB. Among 415 tested volunteers, three distinct cognitive groups were found, mainly based on working memory and episodic memory scores: group 1 (94% young adults) was composed almost exclusively of young adults, while groups 2 (82% older adults) and 3 (95% older adults) were composed predominantly of older adults. Although group 1was the youngest group with the highest level of education compared to the other groups, 18% of young people shared similar performances with older group 2 while 5% shared cognitive similarities with group 3. As compared to group 1, predominantly older groups 2 and 3 had equally lower scores in working memory, but as compared to group 3, group 2 showed greater performances in reaction time, sustained attention, and episodic memory. When the hierarchical cluster and discriminant function analyzes were limited to the same age group, we found 4 and 5 distinct clusters among young adults and older people respectively. Episodic memory, sustained attention, and reaction time most contributed to group formation in the older, while working memory and sustained attention contributed to cluster formation of young adults. Cognitive variability across subjects showed significant dispersion in rapid visual processing, spatial working memory, reaction time, and paired associated learning. The comparative analysis of these differences showed that they do not occur in the same direction and magnitude between individuals, cognitive domains, and tasks. We found that older adults with greater education and a more active lifestyle must have greater cognitive reserve and, therefore, deviated less from the reference group of young adults. Taken together, our data highlight the importance of studying variability as an instrument for the early detection of subtle cognitive declines and to interpret results that deviate from normality.
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