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Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux

Small alterations in extracellular acidity are potentially important modulators of neuronal signaling within the vertebrate retina. Here we report a novel extracellular acidification mechanism mediated by glial cells in the retina. Using self-referencing H+-selective microelectrodes to measure extra...

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Autores principales: Tchernookova, Boriana K., Heer, Chad, Young, Marin, Swygart, David, Kaufman, Ryan, Gongwer, Michael, Shepherd, Lexi, Caringal, Hannah, Jacoby, Jason, Kreitzer, Matthew A., Malchow, Robert Paul
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821311/
https://www.ncbi.nlm.nih.gov/pubmed/29466379
http://dx.doi.org/10.1371/journal.pone.0190893
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author Tchernookova, Boriana K.
Heer, Chad
Young, Marin
Swygart, David
Kaufman, Ryan
Gongwer, Michael
Shepherd, Lexi
Caringal, Hannah
Jacoby, Jason
Kreitzer, Matthew A.
Malchow, Robert Paul
author_facet Tchernookova, Boriana K.
Heer, Chad
Young, Marin
Swygart, David
Kaufman, Ryan
Gongwer, Michael
Shepherd, Lexi
Caringal, Hannah
Jacoby, Jason
Kreitzer, Matthew A.
Malchow, Robert Paul
author_sort Tchernookova, Boriana K.
collection PubMed
description Small alterations in extracellular acidity are potentially important modulators of neuronal signaling within the vertebrate retina. Here we report a novel extracellular acidification mechanism mediated by glial cells in the retina. Using self-referencing H+-selective microelectrodes to measure extracellular H+ fluxes, we show that activation of retinal Müller (glial) cells of the tiger salamander by micromolar concentrations of extracellular ATP induces a pronounced extracellular H+ flux independent of bicarbonate transport. ADP, UTP and the non-hydrolyzable analog ATPγs at micromolar concentrations were also potent stimulators of extracellular H+ fluxes, but adenosine was not. The extracellular H+ fluxes induced by ATP were mimicked by the P2Y1 agonist MRS 2365 and were significantly reduced by the P2 receptor blockers suramin and PPADS, suggesting activation of P2Y receptors. Bath-applied ATP induced an intracellular rise in calcium in Müller cells; both the calcium rise and the extracellular H+ fluxes were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin and when the PLC-IP3 signaling pathway was disrupted with 2-APB and U73122. The anion transport inhibitor DIDS also markedly reduced the ATP-induced increase in H+ flux while SITS had no effect. ATP-induced H+ fluxes were also observed from Müller cells isolated from human, rat, monkey, skate and lamprey retinae, suggesting a highly evolutionarily conserved mechanism of potential general importance. Extracellular ATP also induced significant increases in extracellular H+ flux at the level of both the outer and inner plexiform layers in retinal slices of tiger salamander which was significantly reduced by suramin and PPADS. We suggest that the novel H+ flux mediated by ATP-activation of Müller cells and of other glia as well may be a key mechanism modulating neuronal signaling in the vertebrate retina and throughout the brain.
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spelling pubmed-58213112018-03-02 Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux Tchernookova, Boriana K. Heer, Chad Young, Marin Swygart, David Kaufman, Ryan Gongwer, Michael Shepherd, Lexi Caringal, Hannah Jacoby, Jason Kreitzer, Matthew A. Malchow, Robert Paul PLoS One Research Article Small alterations in extracellular acidity are potentially important modulators of neuronal signaling within the vertebrate retina. Here we report a novel extracellular acidification mechanism mediated by glial cells in the retina. Using self-referencing H+-selective microelectrodes to measure extracellular H+ fluxes, we show that activation of retinal Müller (glial) cells of the tiger salamander by micromolar concentrations of extracellular ATP induces a pronounced extracellular H+ flux independent of bicarbonate transport. ADP, UTP and the non-hydrolyzable analog ATPγs at micromolar concentrations were also potent stimulators of extracellular H+ fluxes, but adenosine was not. The extracellular H+ fluxes induced by ATP were mimicked by the P2Y1 agonist MRS 2365 and were significantly reduced by the P2 receptor blockers suramin and PPADS, suggesting activation of P2Y receptors. Bath-applied ATP induced an intracellular rise in calcium in Müller cells; both the calcium rise and the extracellular H+ fluxes were significantly attenuated when calcium re-loading into the endoplasmic reticulum was inhibited by thapsigargin and when the PLC-IP3 signaling pathway was disrupted with 2-APB and U73122. The anion transport inhibitor DIDS also markedly reduced the ATP-induced increase in H+ flux while SITS had no effect. ATP-induced H+ fluxes were also observed from Müller cells isolated from human, rat, monkey, skate and lamprey retinae, suggesting a highly evolutionarily conserved mechanism of potential general importance. Extracellular ATP also induced significant increases in extracellular H+ flux at the level of both the outer and inner plexiform layers in retinal slices of tiger salamander which was significantly reduced by suramin and PPADS. We suggest that the novel H+ flux mediated by ATP-activation of Müller cells and of other glia as well may be a key mechanism modulating neuronal signaling in the vertebrate retina and throughout the brain. Public Library of Science 2018-02-21 /pmc/articles/PMC5821311/ /pubmed/29466379 http://dx.doi.org/10.1371/journal.pone.0190893 Text en © 2018 Tchernookova et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Tchernookova, Boriana K.
Heer, Chad
Young, Marin
Swygart, David
Kaufman, Ryan
Gongwer, Michael
Shepherd, Lexi
Caringal, Hannah
Jacoby, Jason
Kreitzer, Matthew A.
Malchow, Robert Paul
Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title_full Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title_fullStr Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title_full_unstemmed Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title_short Activation of retinal glial (Müller) cells by extracellular ATP induces pronounced increases in extracellular H+ flux
title_sort activation of retinal glial (müller) cells by extracellular atp induces pronounced increases in extracellular h+ flux
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5821311/
https://www.ncbi.nlm.nih.gov/pubmed/29466379
http://dx.doi.org/10.1371/journal.pone.0190893
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