Votyakova 2001 J Neurochem

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Votyakova TV, Reynolds IJ (2001) DeltaPsi(m)-Dependent and -independent production of reactive oxygen species by rat brain mitochondria. J Neurochem 79:266-77.

» PMID:11677254 Open Access

Votyakova TV, Reynolds IJ (2001) J Neurochem

Abstract: Mitochondria are widely believed to be the source of reactive oxygen species (ROS) in a number of neurodegenerative disease states. However, conditions associated with neuronal injury are accompanied by other alterations in mitochondrial physiology, including profound changes in the mitochondrial membrane potential ΔΨm. In this study, we have investigated the effects of ΔΨm on ROS production by rat brain mitochondria using the fluorescent peroxidase substrates scopoletin and Amplex red. The highest rates of mitochondrial ROS generation were observed while mitochondria were respiring on the complex II substrate succinate. Under this condition, the majority of the ROS signal was derived from reverse electron transport to complex I, because it was inhibited by rotenone. This mode of ROS generation is very sensitive to depolarization of ΔΨm, and even the depolarization associated with ATP generation was sufficient to inhibit ROS production. Mitochondria respiring on the complex I substrates, glutamate and malate, produce very little ROS until complex I is inhibited with rotenone, which is also consistent with complex I being the major site of ROS generation. This mode of oxidant production is insensitive to changes in ΔΨm. With both substrates, ubiquinone-derived ROS can be detected, but they represent a more minor component of the overall oxidant signal. These studies demonstrate that rat brain mitochondria can be effective producers of ROS. However, the optimal conditions for ROS generation require either a hyperpolarized membrane potential or a substantial level of complex I inhibition.

Cited by

  • Komlodi et al (2022) Hydrogen peroxide production, mitochondrial membrane potential and the coenzyme Q redox state measured at tissue normoxia and experimental hyperoxia in heart mitochondria. MitoFit Preprints 2021 (in prep)
  • Komlódi et al (2022) The protonmotive force - not merely membrane potential. MitoFit Preprints 2022 (in prep)

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MitoFit 2021 Tissue normoxia, MitoFit 2022 pmF