Delayed neuronal preconditioning by NS1619 is independent of calcium activated potassium channels

Authors

  • Tamás Gáspár,

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    Search for more papers by this author
  • Prasad Katakam,

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    Search for more papers by this author
  • James A. Snipes,

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    Search for more papers by this author
  • Béla Kis,

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    2. Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
    Search for more papers by this author
  • Ferenc Domoki,

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    2. Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
    Search for more papers by this author
  • Ferenc Bari,

    1. Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
    Search for more papers by this author
  • David W. Busija

    1. Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina, USA
    Search for more papers by this author

Address correspondence and reprint requests to Tamás Gáspár, Department of Physiology and Pharmacology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, NC 27157-1010, USA. E-mail: tgaspar@wfubmc.edu

Abstract

1,3-Dihydro-1-[2-hydroxy-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS1619), a potent activator of the large conductance Ca2+ activated potassium (BKCa) channel, has been demonstrated to induce preconditioning (PC) in the heart. The aim of our study was to test the delayed PC effect of NS1619 in rat cortical neuronal cultures against oxygen-glucose deprivation, H2O2, or glutamate excitotoxicity. We also investigated its actions on reactive oxygen species (ROS) generation, and on mitochondrial and plasma membrane potentials. Furthermore, we tested the activation of the phosphoinositide 3-kinase (PI3K) signaling pathway, and the effect of NS1619 on caspase-3/7. NS1619 dose-dependently protected the cells against the toxic insults, and the protection was completely blocked by a superoxide dismutase mimetic and a PI3K antagonist, but not by BKCa channel inhibitors. Application of NS1619 increased ROS generation, depolarized isolated mitochondria, hyperpolarized the neuronal cell membrane, and activated the PI3K signaling cascade. However, only the effect on the cell membrane potential was antagonized by BKCa channel blockers. NS1619 inhibited the activation of capase-3/7. In summary, NS1619 is a potent inducer of delayed neuronal PC. However, the neuroprotective effect seems to be independent of cell membrane and mitochondrial BKCa channels. Rather it is the consequence of ROS generation, activation of the PI3K pathway, and inhibition of caspase activation.

Ancillary