Navegando por Palavras-chave "astrocyte"

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    Far beyond the motor neuron: the role of glial cells in amyotrophic lateral sclerosis
    (Assoc Arquivos Neuro- Psiquiatria, 2016) Souza, Paulo Victor Sgobbi de [UNIFESP]; Pinto, Wladimir Bocca Vieira de Rezende [UNIFESP]; Rezende Filho, Flavio Moura [UNIFESP]; Oliveira, Acary Souza Bulle [UNIFESP]
    Motor neuron disease is one of the major groups of neurodegenerative diseases, mainly represented by amyotrophic lateral sclerosis. Despite wide genetic and biochemical data regarding its pathophysiological mechanisms, motor neuron disease develops under a complex network of mechanisms not restricted to the unique functions of the alpha motor neurons but which actually involve diverse functions of glial cell interaction. This review aims to expose some of the leading roles of glial cells in the physiological mechanisms of neuron-glial cell interactions and the mechanisms related to motor neuron survival linked to glial cell functions.
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    Long-Term Astroglial Reaction and Neuronal Plasticity in the Subcortical Visual Pathways After a Complete Ablation of Telencephalon in Pigeons (Columba livia)
    (Informa Healthcare, 2009-01-01) Cerutti, Suzete Maria [UNIFESP]; Gomide, Vania Canterucci; Ferrari, Elenis A. de Moraes; Chadi, Gerson; Universidade de São Paulo (USP); Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP)
    This paper analyzes the astroglial and neuronal responses in subtelencephalic structures, following a bilateral ablation of the telencephalon in the Columba livia pigeons. Control birds received a sham operation. Four months later the birds were sacrificed and their brains processed for glial fribillary acid protein (GFAP) and neurofilament immunohistochemistry, markers for astrocytes and neurons, respectively. Computer-assisted image analysis was employed for quantification of the immunoreactive labeling in the nucleus rotundus (N.Rt) and the optic tectum (OT) of the birds. An increased number of GFAP immunoreactive astrocytes were found in several subregions of the N.Rt (p .001), as well as in layers 1, 2cd, 3, and 6 of the OT (p .001) of the lesioned animals. Neurofilament immunoreactivity decreased massively in the entire N.Rt of the lesioned birds; however, remaining neurons with healthy aspect showing large cytoplasm and ramified branches were detected mainly in the periphery of the nucleus. in view of the recently described paracrine neurotrophic properties of the activated astrocytes, the data of the present study may suggest a long-lasting neuroglial interaction in regions of the lesioned bird brain far from injury. Such events may trigger neuronal plasticity in remaining brain structures that may lead spontaneous behavior recovery as the one promoted here even after a massive injury.
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    Thyroid hormone treated astrocytes induce maturation of cerebral cortical neurons through modulation of proteoglycan levels
    (Frontiers Research Foundation, 2013-08-12) Dezonne, Romulo S.; Stipursky, Joice; Araujo, Ana P. B.; Nones, Jader; Pavao, Mauro S. G.; Porcionatto, Marimelia [UNIFESP]; Gomes, Flavia C. A.; Universidade Federal do Rio de Janeiro (UFRJ); Universidade Federal de São Paulo (UNIFESP)
    Proper brain neuronal circuitry formation and synapse development is dependent on specific cues, either genetic or epigenetic, provided by the surrounding neural environment. Within the sesignals, thyroid hormones (T3 and T4) play crucial role in several steps of brain morphogenesis including proliferation of progenitor cells, neuronal differentiation, maturation, migration, and synapse formation. the lack of thyroid hormones during childhood is associated with several impair neuronal connections, cognitive deficits, and mental disorders. Many of the thyroid hormones effects are mediated by astrocytes, although the mechanisms underlying these events are still unknown. in this work, we investigated the effect of 3,5,3'-triiodothyronine-treated (T3-treated) astrocytes on cerebral cortex neuronal differentiation. Culture of neural progenitors from embryonic cerebral cortex mice onto T3-treated astrocyte monolayers yielded an increment in neuronal population, followed by enhancement of neuronal maturation, arborization and neurite outgrowth. in addition, real time PCR assays revealed an increase in the levels of the heparan sulfate proteoglycans, Glypican 1(GPC-1) and Syndecans 3 e 4 (SDC-3 e SDC-4), followed by a decrease in the levels of the chondroitin sulfate proteoglycan, Versican. Disruption of glycosaminoglycan chains by chondroitinase AC or heparanase III completely abolished the effects of T3-treated astrocytes on neuronal morphogenesis. Our work provides evidence that astrocytes are key mediators of T3 actions on cerebral cortex neuronal development and identified potential molecules and pathways involved in neurite extension; which might eventually contribute to a better understanding of axonal regeneration, synapse formation, and neuronal circuitry recover.