Navegando por Autor "PAULO, Dario Carvalho"

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Acesso aberto (Open Access)
Caracterização morfológica de astrócitos da formação hipocampal de maçaricos da espécie calidris pusilla durante a migração e em período de invernada
(Universidade Federal do Pará, 2017-04-12) PAULO, Dario Carvalho; DINIZ, Cristovam Guerreiro; http://lattes.cnpq.br/1025250990755299; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
The semipalmated sandpiper Calidris pusilla (C. pusilla) is a long-distance migrant shorebird that leaves every year, its breeding habitats in the southern tundra in Canada and Alaska, escaping from winter, towards the coastal line in South America. Before they cross the Atlantic Ocean, they stopover Bay of Fundy on the Atlantic coast of North America, where they increase triglycerides in adipose tissue, to attend the vigorous energetic demands of the 5,300-kilometer non-stop flight over the ocean. Because bioenergetic and redox activity of astrocytes would be under intense demand to sustain neuronal activity and survival during long-distance transatlantic migration, we hypothesize that astrocytes morphological changes may become readily visible in the wintering birds. To test this hypothesis, GFAP immunolabeled astrocytes were selected from sections of the hippocampal formation, an area that has been proposed to play a central role in the integration of multisensory spatial information for navigation. We quantified and compared hippocampal three-dimensional morphological features of astrocytes of adult migrating, captured on the Bay of Fundy, Canada, with hippocampal astrocytes from birds captured in the coastal region of Bragança, Brazil, during the wintering period. To select astrocytes for microscopic 3D reconstructions we used a random and systematic unbiased sampling approach. Using hierarchical cluster and discriminant analysis of 3D morphometric features to classify astrocytes, we found two morphological phenotypes (designated types I and II) both in migrating and wintering individuals. Although in remarkable different extent, the morphological complexities of both types of astrocytes were reduced after long-distance non-stop flight. Indeed, birds captured in the coastal region of Bragança, Brazil, during the wintering period, showed less complex astrocytic morphology than individuals captured in the Bay of Fundy, Canada, during fall migration. Because the reduction in complexity was much more intense in type I than in type II astrocytes, we suggest that these distinct morphological phenotypes may be associated with different physiological roles during migration. Indeed, as compared to type I, most type II astrocytes did not change significantly their morphology after the long-distance flight and many of them (72.5%) revealed unequivocally connection with blood vessels, whereas type I revealed only 27.5%.
Acesso aberto (Open Access)
Enriched environment contributes to recovery of visual acuity and increases perineuronal nets in monocular-deprived animals
(2001-06) TRÉVIA, Nonata; ALMEIDA, Izabela Negrão Frota de; OLIVEIRA, Poliana Sampaio; WARWICK, Laura Vianna; MARQUES, Viviane; SANTOS, Denise Cristina dos; VIEGAS, Maria Luana Carvalho; DINIZ, Cristovam Wanderley Picanço; PAULO, Dario Carvalho
The aim of the present study was to analyze the influence of enriched environment on the distribution of perineuronal nets (PNNs) using a stereogically based unbiased protocol and visual acuity in adult Swiss albino mice that underwent monocular deprivation during the critical period of postnatal development. Eight female Swiss albino mice were monocular deprived were removed and cut at 70 µm thickness in a vibratome and processed for lectin histochemical staining with Wisteria floribunda agglutinin (WFA). Architectonic limits of area 17 were conspicuously defined by WFA histochemical staining, and the optical fractionator stereological method was applied to estimate the total number of PNNs in the supragranular, granular, and infragranular layers. All groups were compared using Student's t-test at a 95% confidence level. Comparative analysis of the average PNN estimations revealed that the EE group had higher PNNs in the supragranular layer (2726.33 ± 405.416, mean ± standard deviation) compared with the SE group (1543.535 ± 260.686; Student's t-test, p = .0495). No differences were found in the other layers. Visual acuity was significantly lower in the SE group (0.55 cycles/degree) than in the EE group (1.06 cycles/degree). Our results suggest that the integrity of the specialized extracellular matrix PNNs of the supragranular layer may be essential for normal visual acuity development.
Acesso aberto (Open Access)
Microglia and neurons in the hippocampus of migratory sandpipers
(Universidade Federal do Pará, 2015-11) DINIZ, Cristovam Guerreiro; MAGALHÃES, Nara Gyzely de Morais; SOUSA, Aline Andrade de; SANTOS FILHO, Carlos; DINIZ, Daniel Guerreiro; LIMA, Camila Mendes de; OLIVEIRA, Marcus Augusto de; PAULO, Dario Carvalho; PEREIRA, Patrick Douglas Corrêa; SHERRY, David Francis
The semipalmated sandpiper Calidris pusilla and the spotted sandpiper Actitis macularia are long- and short-distance migrants, respectively. C. pusilla breeds in the sub-arctic and mid-arctic tundra of Canada and Alaska and winters on the north and east coasts of South America. A. macularia breeds in a broad distribution across most of North America from the treeline to the southern United States. It winters in the southern United States, and Central and South America. The autumn migration route of C. pusilla includes a non-stop flight over the Atlantic Ocean, whereas autumn route of A. macularia is largely over land. Because of this difference in their migratory paths and the visuo-spatial recognition tasks involved, we hypothesized that hippocampal volume and neuronal and glial numbers would differ between these two species. A. macularia did not differ from C. pusilla in the total number of hippocampal neurons, but the species had a larger hippocampal formation and more hippocampal microglia. It remains to be investigated whether these differences indicate interspecies differences or neural specializations associated with different strategies of orientation and navigation.