Consulta: subjectFacets:"Astrocytes"
Registros recuperados: 13
Data/hora: 09/06/2024 07:33:19

NEUROTOXIC POTENTIAL OF TRICHLORFON TO MULTIPLE SUBLETHAL DOSES IN WISTAR RATS
Provedor de dados: 37
Autores: TAPIERO HERNÁNDEZ,YACSON; RONDÓN BARRAGÁN,IANG; CÉSPEDES RUBIO,ANGEL.
The organophosphates used for pest control induce sensory, motor and psychiatric disturbances after chronic exposure. The ester type is the cause of the intermediate syndrome and delayed neuropathy, in which the white and gray matter in the brain are severely affected.The aim of this study was to evaluate the effect of multiple sublethal doses of Trichlorfon on neurons, astrocytes and myelinated tissue in a rat model of brain neurotoxicity. Trichlorfon (metrifonate) was administered to adult Wistar rats at doses of 11 or 22 Î¼g/kg by oral gavage every seven days for four or eight weeks (four experimental groups) and a control group (placebo). One week after the last dose, animals were euthanized and the brains perfused, removed and cut into coronal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Astrocytes; Myelin; Neurons; Organophosphates; Toxicology.
Ano: 2013
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2013000300007

Modulators of axonal growth and guidance at the brain midline with special reference to glial heparan sulfate proteoglycans
Provedor de dados: 42
Autores: CAVALCANTE,LENY A.; GARCIA-ABREU,JOSÉ; MOURA NETO,VIVALDO; SILVA,LUIZ CLAUDIO; WEISSMÜLLER,GILBERTO.
Bilaterally symmetric organisms need to exchange information between the left and right sides of their bodies to integrate sensory input and to coordinate motor control. Thus, an important choice point for developing axons is the Central Nervous System (CNS) midline. Crossing of this choice point is influenced by highly conserved, soluble or membrane-bound molecules such as the L1 subfamily, laminin, netrins, slits, semaphorins, Eph-receptors and ephrins, etc. Furthermore, there is much circumstantial evidence for a role of proteoglycans (PGs) or their glycosaminoglycan (GAG) moieties on axonal growth and guidance, most of which was derived from simplified models. A model of intermediate complexity is that of cocultures of young neurons and astroglial...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Astrocytes; Axon growth; Extracellular matrix; Heparan sulfate; Midline; Midbrain.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652002000400010

Regional density of glial cells in the rat corpus callosum
Provedor de dados: 48
Autores: Reyes-Haro,Daniel; Mora-Loyola,Ernesto; Soria-Ortiz,Berenice; García-Colunga,Jesús.
Axons and glial cells are the main components of white matter. The corpus callosum (CC) is the largest white matter tract in mammals; in rodents, 99% of the cells correspond to glia after postnatal day 5 (P5). The area of the CC varies through life and regional differences related to the number of axons have been previously described. Whether glial cell density varies accordingly is unknown; thus the aim of this study was to estimate glial cell density for the genu, body and splenium -the three main regions of CC-, of P6 and P30 rats. Here we report that the density of CC glial cells reduced by ~10% from P6 to P30. Even so, the density of astrocytes showed a slight increase (+6%), probably due to differentiation of glioblasts. Interestingly, glial cell...
Tipo: Journal article
Palavras-chave: Astrocytes; Corpus callosum; Genu; Glial cells; Splenium.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602013000100004

Investigation of toxic factors affecting cells of rat brains exposed to 3-methylcatechol
Provedor de dados: 52
Autores: Barreto,George Emílio Sampaio; Oliveira,Elineusa Silva de; Villar,Flávio Augusto Guerreiro Aragão de; Santos,Gleide Souza dos; Lima,Rute Maria Ferreira; Costa,Silvia Lima; Costa,Maria de Fátima Dias; Egito,Eryvaldo Sócrates Tabosa; El-Bachá,Ramon Santos.
The aim of this work was to study the effects of 3MC on the peroxidation of biomolecules in nuclear fractions and nonsynaptic mitochondrial respiration in organelles obtained from rat brains. The cytotoxicity towards rat primary astrocytes in vitro was also tested. 3MC at 1mM oxidized consuming oxygen at a rate of 1.98 ± 0.19 µM.min-1 and formed reactive quinones. At the same concentration, 3MC induced peroxidation of biomolecules in nuclear fractions obtained from rat brain homogenates and inhibited state 2 FADH2-linked respiration in nonsynaptic mitochondria. Furthermore, 3MC oxidized in the culture medium, leading to the formation of quinones. This toluene metabolite was cytotoxic to rat primary astrocytes. The concentration that killed 50% of cells...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Astrocytes; Brain; Cytotoxicity; 3-methylcatechol; Peroxidation; Respiration.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132007000500012

Possible etiologies for tropical spastic paraparesis and human T lymphotropic virus I-associated myelopathy
Provedor de dados: 56
Autores: Zaninovic',V.
The epidemiology of tropical spastic paraparesis/human T lymphotropic virus I (HTLV-I)-associated myelopathy (TSP/HAM) is frequently inconsistent and suggests environmental factors in the etiology of these syndromes. The neuropathology corresponds to a toxometabolic or autoimmune process and possibly not to a viral disease. Some logical hypotheses about the etiology and physiopathology of TSP and HAM are proposed. Glutamate-mediated excitotoxicity, central distal axonopathies, cassava, lathyrism and cycad toxicity may explain most cases of TSP. The damage caused to astrocytes and to the blood-brain barrier by HTLV-I plus xenobiotics may explain most cases of HAM. Analysis of the HTLV-I/xenobiotic ratio clarifies most of the paradoxical epidemiology of TSP...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: TSP/HAM; Paradoxical epidemiology; Toxic and toxoviral etiologies; HTLV-I; Glutamate; Astrocytes; Cycads; Cassava.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000100001

Glial cell activity is maintained during prolonged inflammatory challenge in rats
Provedor de dados: 56
Autores: Borges,B.C.; Rorato,R.; Antunes-Rodrigues,J; Elias,L.L.K.
We evaluated the expression of glial fibrillary acidic protein (GFAP), glutamine synthetase (GS), ionized calcium binding adaptor protein-1 (Iba-1), and ferritin in rats after single or repeated lipopolysaccharide (LPS) treatment, which is known to induce endotoxin tolerance and glial activation. Male Wistar rats (200-250 g) received ip injections of LPS (100 µg/kg) or saline for 6 days: 6 saline (N = 5), 5 saline + 1 LPS (N = 6) and 6 LPS (N = 6). After the sixth injection, the rats were perfused and the brains were collected for immunohistochemistry. After a single LPS dose, the number of GFAP-positive cells increased in the hypothalamic arcuate nucleus (ARC; 1 LPS: 35.6 ± 1.4 vs control: 23.1 ± 2.5) and hippocampus (1 LPS: 165.0 ± 3.0 vs control: 137.5...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: LPS tolerance; Astrocytes; Microglia; Glial fibrillary acidic protein; Iba-1; Glutamine synthetase; Ferritin.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000800014

Localization of NMDA receptors in the cerebral cortex: a schematic overview
Provedor de dados: 56
The fundamental role of N-methyl-D-aspartate (NMDA) receptors in many cortical functions has been firmly defined, as has its involvement in a number of neurological and psychiatric diseases. However, until recently very little was known about the anatomical localization of NMDA receptors in the cerebral cortex of mammals. The recent application of molecular biological techniques to the study of NMDA receptors has provided specific tools which have greatly expanded our understanding of the localization of NMDA receptors in the cerebral cortex. In particular, immunocytochemical studies on the distribution of cortical NMDA receptors have shown that NMDA receptors are preferentially localized on dendritic spines, have disclosed an unknown fraction of...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Glutamate; Ionotropic receptors; Autoreceptors; Heteroreceptors; Astrocytes; Neuron-glia signaling.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000500001

Involvement of glutamate and reactive oxygen species in methylmercury neurotoxicity
Provedor de dados: 56
Autores: Aschner,M.; Syversen,T.; Souza,D.O.; Rocha,J.B.T.; Farina,M.
This review addresses the mechanisms of methylmercury (MeHg)-induced neurotoxicity, specifically examining the role of oxidative stress in mediating neuronal damage. A number of critical findings point to a central role for astrocytes in mediating MeHg-induced neurotoxicity as evidenced by the following observations: a) MeHg preferentially accumulates in astrocytes; b) MeHg specifically inhibits glutamate uptake in astrocytes; c) neuronal dysfunction is secondary to disturbances in astrocytes. The generation of reactive oxygen species (ROS) by MeHg has been observed in various experimental paradigms. For example, MeHg enhances ROS formation both in vivo (rodent cerebellum) and in vitro (isolated rat brain synaptosomes), as well as in neuronal and mixed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Methylmercury neurotoxicity; Oxidative stress; Glutamate and selenocompounds; Reactive oxygen species; Astrocytes.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000300001

Cell migration in the postnatal subventricular zone
Provedor de dados: 56
Autores: Menezes,J.R.L.; Marins,M.; Alves,J.A.J.; Fróes,M.M.; Hedin-Pereira,C.
New neurons are constantly added to the olfactory bulb of rodents from birth to adulthood. This accretion is not only dependent on sustained neurogenesis, but also on the migration of neuroblasts and immature neurons from the cortical and striatal subventricular zone (SVZ) to the olfactory bulb. Migration along this long tangential pathway, known as the rostral migratory stream (RMS), is in many ways opposite to the classical radial migration of immature neurons: it is faster, spans a longer distance, does not require radial glial guidance, and is not limited to postmitotic neurons. In recent years many molecules have been found to be expressed specifically in this pathway and to directly affect this migration. Soluble factors with inhibitory, attractive...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Postnatal neurogenesis; Chain migration; Rostral migratory stream; Astrocytes; Gap junctions; Radial glia.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001200002

Astroglial cells derived from lateral and medial midbrain sectors differ in their synthesis and secretion of sulfated glycosaminoglycans
Provedor de dados: 56
Autores: Onofre,G.R.; Werneck,C.C.; Mendes,F.A.; Garcia-Abreu,J.; Moura Neto,V.; Cavalcante,L.A.; Silva,L.C.F.
Astroglial cells derived from lateral and medial midbrain sectors differ in their abilities to support neuritic growth of midbrain neurons in cocultures. These different properties of the two types of cells may be related to the composition of their extracellular matrix. We have studied the synthesis and secretion of sulfated glycosaminoglycans (GAGs) by the two cell types under control conditions and ß-D-xyloside-stimulated conditions, that stimulate the ability to synthesize and release GAGs. We have confirmed that both cell types synthesize and secrete heparan sulfate and chondroitin sulfate. Only slight differences were observed between the proportions of the two GAGs produced by the two types of cells after a 24-h labeling period. However, a marked...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Glycosaminoglycans; Astrocytes; Neuron-glia interactions; Midbrain.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000200014

Sulfated proteoglycans as modulators of neuronal migration and axonal decussation in the developing midbrain
Provedor de dados: 56
Autores: Cavalcante,L.A.; Garcia-Abreu,J.; Mendes,F.A.; Moura Neto,V.; Silva,L.C.F.; Onofre,G.; Weissmüller,G.; Carvalho,S.L.
Proteoglycans are abundant in the developing brain and there is much circumstantial evidence for their roles in directional neuronal movements such as cell body migration and axonal growth. We have developed an in vitro model of astrocyte cultures of the lateral and medial sectors of the embryonic mouse midbrain, that differ in their ability to support neuritic growth of young midbrain neurons, and we have searched for the role of interactive proteins and proteoglycans in this model. Neurite production in co-cultures reveals that, irrespective of the previous location of neurons in the midbrain, medial astrocytes exert an inhibitory or nonpermissive effect on neuritic growth that is correlated to a higher content of both heparan and chondroitin sulfates...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Astrocytes; Axonal growth; Chondroitin sulfate; Heparan sulfate; Midline; Midbrain.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000800005

Control of the phosphorylation of the astrocyte marker glial fibrillary acidic protein (GFAP) in the immature rat hippocampus by glutamate and calcium ions: possible key factor in astrocytic plasticity
Provedor de dados: 56
The present review describes recent research on the regulation by glutamate and Ca2+ of the phosphorylation state of the intermediate filament protein of the astrocytic cytoskeleton, glial fibrillary acidic protein (GFAP), in immature hippocampal slices. The results of this research are discussed against a background of modern knowledge of the functional importance of astrocytes in the brain and of the structure and dynamic properties of intermediate filament proteins. Astrocytes are now recognized as partners with neurons in many aspects of brain function with important roles in neural plasticity. Site-specific phosphorylation of intermediate filament proteins, including GFAP, has been shown to regulate the dynamic equilibrium between the polymerized and...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Astrocytes; Glial fibrillary acidic protein; GFAP; Glutamate receptors; Protein phosphorylation; Calcium; Intermediate filament dynamics.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000300005

Early and late neuropathological features of meningoencephalitis associated with Maraba virus infection
Provedor de dados: 56
Autores: Maia-Farias,A.; Lima,C.M.; Freitas,P.S.L.; Diniz,D.G.; Rodrigues,A.P.D.; Quaresma,J.A.S.; Diniz,C.W. Picanço; Diniz,J.A.
Maraba virus is a member of the genus Vesiculovirus of the Rhabdoviridae family that was isolated in 1983 from sandflies captured in the municipality of Maraba, state of Pará, Amazônia, Brazil. Despite 30 years having passed since its isolation, little is known about the neuropathology induced by the Maraba virus. Accordingly, in this study the histopathological features, inflammatory glial changes, cytokine concentrations, and nitric oxide activity in the encephalon of adult mice subjected to Maraba virus nostril infection were evaluated. The results showed that 6 days after intranasal inoculation, severe neuropathological-associated disease signs appeared, including edema, necrosis and pyknosis of neurons, generalized congestion of encephalic vessels,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Maraba virus; Vesiculovirus; Microglia; Astrocytes; Cytokines; Nitric oxide.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2020000400610