title: Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells.
abstract: Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH) is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1-10 mM) showed that 5-10 mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells), while neurons responded to 50 mM KCl (labeled as βIII tubulin positive cells). BBG 100 nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70 μM and MK-801 20 μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG) at 5 mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s) protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H2O2. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit.
authors.affiliation: Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Hercules R
authors.initials: HR
authors.lastname: Freitas
authors.affiliation: Institute of Biological Sciences, Center for Health Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Ferraz
authors.affiliation: Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.|Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Ferreira
authors.affiliation: Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Victor T
authors.initials: VT
authors.lastname: Ribeiro-Resende
authors.affiliation: Laboratory of Neurogenesis, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Luciana B
authors.initials: LB
authors.lastname: Chiarini
authors.affiliation: Institute of Biology, Federal University of Pará, Belém, PA, Brazil.
authors.forename: José Luiz M
authors.initials: JL
authors.lastname: do Nascimento
authors.affiliation: Institute of Biology, Federal University of Pará, Belém, PA, Brazil.
authors.forename: Karen Renata H
authors.initials: KR
authors.lastname: Matos Oliveira
authors.affiliation: Institute of Biology, Federal University of Pará, Belém, PA, Brazil.
authors.forename: Tiago de Lima
authors.initials: Tde L
authors.lastname: Pereira
authors.affiliation: Laboratory of Inflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil.
authors.forename: Leonardo G B
authors.initials: LG
authors.lastname: Ferreira
authors.affiliation: Laboratory Neuropharmacology, Dept Physiology and Pharmacology, Federal Fluminense University, Niterói, Brazil.
authors.forename: Regina C
authors.initials: RC
authors.lastname: Kubrusly
authors.affiliation: Laboratory of Toxoplasmosis, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil.
authors.forename: Robson X
authors.initials: RX
authors.lastname: Faria
authors.affiliation: Institute of Biology, Federal University of Pará, Belém, PA, Brazil.
authors.forename: Anderson Manoel
authors.initials: AM
authors.lastname: Herculano
authors.affiliation: Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Ricardo A de Melo
authors.initials: RA
authors.lastname: Reis
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D030161:Avian Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000494:pharmacology*; D019803:Glutathione Disulfide / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism; D012160:Retina / Q000166:cytology* / Q000196:embryology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D030161:Avian Proteins; D058486:Receptors, Purinergic P2X7; D005680:gamma-Aminobutyric Acid; D005978:Glutathione; D002118:Calcium; D019803:Glutathione Disulfide