Activation of a novel non-selective cation channel by alloxan and H2O2 in the rat insulin-secreting cell line CRI-G1

J Physiol. 1997 May 15;501 ( Pt 1)(Pt 1):59-66. doi: 10.1111/j.1469-7793.1997.059bo.x.

Abstract

1. Alloxan and its auto-oxidation product hydrogen peroxide (H2O2) irreversibly depolarize insulinoma cells by opening a non-selective cation channel. The channel opened is characterized by a linear current-voltage relation with a conductance of approximately 70 pS and very slow kinetics (of the order of seconds). 2. Cells are protected against the alloxan-induced channel opening and consequent cell depolarization by the presence of H2O2 and hydroxyl radical scavengers. 3. The free radical-activated non-selective cation channel is not operative in isolated patches but can be activated by the application of beta-NAD+ to the cytoplasmic aspect of the membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alloxan / pharmacology*
  • Animals
  • Cell Polarity / drug effects
  • Cysteine / pharmacology
  • Free Radical Scavengers / pharmacology
  • Hydrogen Peroxide / metabolism*
  • Insulinoma / metabolism*
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / metabolism*
  • Membrane Potentials / drug effects
  • Niacinamide / pharmacology
  • Patch-Clamp Techniques
  • Rats
  • Reactive Oxygen Species / metabolism
  • Thiourea / analogs & derivatives
  • Thiourea / pharmacology
  • Tumor Cells, Cultured

Substances

  • Free Radical Scavengers
  • Reactive Oxygen Species
  • Niacinamide
  • Alloxan
  • 1,3-dimethylthiourea
  • Hydrogen Peroxide
  • Thiourea
  • Cysteine