Specific combinations of Ca2+ channel inhibitors reduce excessive Ca2+ influx as a consequence of oxidative stress and increase neuronal and glial cell viability in vitro

Ryan Doig, Carole A. Bartlett, Nicole M. Smith, Stuart I. Hodgetts, Sarah A. Dunlop, Livia Hool, Melinda Fitzgerald

    Research output: Contribution to journalArticle

    9 Citations (Scopus)
    320 Downloads (Pure)

    Abstract

    Combinations of Ca2+ channel inhibitors have been proposed as an effective means to prevent excess Ca2+ flux and death of neurons and glia following neurotrauma in vivo. However, it is not yet known if beneficial outcomes such as improved viability have been due to direct effects on intracellular Ca2+ concentrations. Here, the effects of combinations of Lomerizine (Lom), 2,3-dioxo-7-(1H-imidazol-1-yl)6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl]acetic acid monohydrate (YM872), 3,5-dimethyl-1-adamantanamine (memantine (Mem)) and/or adenosine 5′-triphosphate periodate oxidized sodium salt (oxATP) to block voltage-gated Ca2+ channels, Ca2+ permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, NMDA receptors and purinergic P2X7 receptors (P2X7R) respectively, on Ca2+ concentration and viability of rat primary mixed cortical (MC) cultures exposed to hydrogen peroxide (H2O2) insult, were assessed. The contribution of ryanodine-sensitive intracellular stores to intracellular Ca2+ concentration was also assessed. Live cell calcium imaging revealed that a 30 min H2O2 insult induced a slow increase in intracellular Ca2+, in part from intracellular sources, associated with loss of cell viability by 6 h. Most combinations of inhibitors that included oxATP significantly decreased Ca2+ influx and increased cell viability when administered simultaneously with H2O2. However, reductions in intracellular Ca2+ concentration were not always linked to improved cell viability. Examination of the density of specific cell subpopulations demonstrated that most combinations of inhibitors that included oxATP preserved NG2+ non-oligodendroglial cells, but preservation of astrocytes and neurons required additional inhibitors. Olig2+ oligodendroglia and ED-1+ activated microglia/macrophages were not preserved by any of the inhibitor combinations. These data indicate that following H2O2 insult, limiting intracellular Ca2+ entry via P2X7R is generally associated with increased cell viability. Protection of NG2+ non-oligodendroglial cells by Ca2+ channel inhibitor combinations may contribute to observed beneficial outcomes in vivo.

    Original languageEnglish
    Pages (from-to)450-462
    Number of pages13
    JournalNeuroscience
    Volume339
    DOIs
    Publication statusPublished - 17 Dec 2016

    Fingerprint Dive into the research topics of 'Specific combinations of Ca2+ channel inhibitors reduce excessive Ca2+ influx as a consequence of oxidative stress and increase neuronal and glial cell viability in vitro'. Together they form a unique fingerprint.

    Cite this