Navegando por Assunto "Aves - migração"

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Acesso aberto (Open Access)
Análise quantitativa de neurônios imunomarcados para parvalbumina no hipocampo e núcleo magnocelular do istmo em Actitis macularius no período de invernada
(Universidade Federal do Pará, 2020-02) GUERREIRO, Luma Cristina Ferreira; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; DINIZ, Daniel Guerreiro; http://lattes.cnpq.br/3269424921125406; https://orcid.org/0000-0001-7369-2165
It is already known that parvalbumin (PV) neurons have their number modified in face of social, multisensory and cognitive stimuli, both in mammals and birds. However, nothing is known about its plasticity in long-distance migratory shorebirds during wintering period. Here we investigated in four distinct temporal windows of the wintering period, the plasticity of PV neurons of two brain areas of the spotted sandpiper (Actitis macularius) which includes in its migratory journey multiple stopovers for feeding and resting. We used PV as a marker of a subpopulation of inhibitory neurons and count them in the hippocampal formation (HF) and magnocellular nucleus of tectal isthmus (IMC). Based on previous evidence that HF is involved in learning and memory and social interaction, and IMC is essential for control of head and neck and eyes movements, we tested the hypothesis that PV neurons would increase in HF and remain unchanged in IMC. For this, we used the optical fractionator to estimate cell number. Brains were processed for PV immunostaining, followed by estimates of the number of PV neurons of the areas of interest. As compared with migratory rest 1, PV neurons estimates showed significant increase in the hippocampal formation of premigration group. We suggest that parvalbuminergic neurons proliferation is part of the adaptive changes of the hippocampal circuits involved with the migratory process back to the reproductive niches in north hemisphere.
Acesso aberto (Open Access)
Mudanças morfológicas nos astrócitos hipocampais no período de invernada em Arenaria interpres
(Universidade Federal do Pará, 2020-02) COSTA, Emanuel Ramos da; DINIZ, Cristovam Guerreiro; http://lattes.cnpq.br/1025250990755299; DINIZ, Daniel Guerreiro; http://lattes.cnpq.br/3269424921125406; https://orcid.org/0000-0001-7369-2165
Astrocytes are essential for lipid neuronal metabolism in long-distance uninterrupted migratory flights, when glucose is not available as the main source of energy. We previously demonstrated in Calidris pusilla that after uninterrupted 5 days transatlantic flight, astrocytes shrink and reduce its number in the hippocampal formation. Here we shifted our attention to the wintering period and tested the hypothesis that as the wintering progresses, hippocampal astrocytes morphological changes following Atlantic crossing, would be recovered. To that end we used Arenaria interpres, which also crosses the Atlantic Ocean and reaches the mangroves of the Amazon River estuary for wintering. Birds were captured in September/October (closer to the arrival in the coast of Bragança - Pará, Brazil for wintering) and in April/May (closer to the departure towards the breeding sites) and had their brains processed for selective GFAP-astrocyte immunolabeling. Three-dimensional reconstructions of the immunostained astrocytes were performed and morphological classification was done based on hierarchical cluster and discriminant analysis of multimodal morphometric features. We found two morphological phenotypes of astrocytes exhibiting distinct morphological complexities after the long-distance non-stop transatlantic flight. Although to a different extent, both morphotypes increased their complexities as wintering period progresses towards the pre-migration window. Taken together, our findings demonstrate that the long-distance non-stop flight and wintering period differentially affected the two astrocytes morphotypes, suggesting distinct physiological roles for these cells. We suggest that morphological recovering during the wintering period, may be part of the adaptive changes of the local hippocampal circuits of A. interpres in preparation for the long journey back to their breeding sites in the north hemisphere.