Effects of H2O2 on membrane potential and [Ca2+]i of cultured rat arterial smooth muscle cells

Biochem Biophys Res Commun. 1995 Apr 6;209(1):139-45. doi: 10.1006/bbrc.1995.1481.

Abstract

The effect of 1 mmol/l H2O2 was studied on the membrane potential and [Ca2+]i with microelectrodes and the fura-2 technique, respectively. H2O2 induced a biphasic increase in [Ca2+]i with a fast transient peak and a subsequent plateau. H2O2 also led to a biphasic hyperpolarization of the cells with a similar time course. This was followed by a slight depolarization after wash-out of H2O2. External Ca2+ free solutions and treatment with the Ca2+ ionophore A23187 (1 mumol/l) abolished the effect of H2O2 on [Ca2+]i and almost entirely reduced the effect on the membrane potential. Phenylephrine (10 mumol/l) or A23187 also induced very similar biphasic hyperpolarizations of the membrane as H2O2 which were fully reversible after wash-out. It is concluded that H2O2 hyperpolarizes the membrane by opening of Ca2+ dependent K+ channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arteries / cytology
  • Arteries / drug effects
  • Arteries / metabolism
  • Calcimycin / pharmacology
  • Calcium / metabolism*
  • Cells, Cultured
  • Charybdotoxin
  • Hydrogen Peroxide / pharmacology*
  • Membrane Potentials / drug effects*
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects*
  • Muscle, Smooth, Vascular / metabolism
  • Phenylephrine / pharmacology
  • Prazosin / pharmacology
  • Rats
  • Scorpion Venoms / pharmacology

Substances

  • Scorpion Venoms
  • Charybdotoxin
  • Phenylephrine
  • Calcimycin
  • Hydrogen Peroxide
  • Calcium
  • Prazosin