Regulation of brain mitochondrial H2O2 production by membrane potential and NAD(P)H redox state Academic Article uri icon

Overview

MeSH Major

  • Brain
  • Brain Chemistry
  • Hydrogen Peroxide
  • Membrane Potentials
  • Mitochondria
  • NADP

abstract

  • Mitochondrial production of reactive oxygen species (ROS) at Complex I of the electron transport chain is implicated in the etiology of neural cell death in acute and chronic neurodegenerative disorders. However, little is known regarding the regulation of mitochondrial ROS production by NADH-linked respiratory substrates under physiologically realistic conditions in the absence of respiratory chain inhibitors. This study used Amplex Red fluorescence measurements of H2O2 to test the hypothesis that ROS production by isolated brain mitochondria is regulated by membrane potential (DeltaPsi) and NAD(P)H redox state. DeltaPsi was monitored by following the medium concentration of the lipophilic cation tetraphenylphosphonium with a selective electrode. NAD(P)H autofluorescence was used to monitor NAD(P)H redox state. While the rate of H2O2 production was closely related to DeltaPsi and the level of NAD(P)H reduction at high values of DeltaPsi, 30% of the maximal rate of H2O2 formation was still observed in the presence of uncoupler (p-trifluoromethoxycarbonylcyanide phenylhydrazone) concentrations that provided for maximum depolarization of DeltaPsi and oxidation of NAD(P)H. Our findings indicate that ROS production by mitochondria oxidizing physiological NADH-dependent substrates is regulated by DeltaPsi and by the NAD(P)H redox state over ranges consistent with those that exist at different levels of cellular energy demand.

publication date

  • September 2003

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed ID

  • 12911618

Additional Document Info

start page

  • 1101

end page

  • 7

volume

  • 86

number

  • 5