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Inhibition of brain monoamine oxidase activity by the generation of hydroxyl radicals: potential implications in

R Soto-Otero1, E Méndez-Alvarez, A Hermida-Ameijeiras

  • 1Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Santiago de Compostela, Spain. bnsoto@usc.es

Life Sciences
|August 8, 2001
PubMed

Insights

Hydroxyl radicals (*OH) irreversibly inhibit monoamine oxidase (MAO) enzymes A and B in rat brains. This finding suggests MAO activity

Area of Science:

  • Neuroscience
  • Biochemistry
  • Enzymology

Background:

  • Monoamine oxidase (MAO) catabolizes neurotransmitters, producing hydrogen peroxide.
  • MAO-derived hydrogen peroxide contributes to oxidative stress in the brain.

Purpose of the Study:

  • To investigate the impact of hydroxyl radical (*OH) production on MAO-A and MAO-B activities.
  • To determine if *OH generation affects MAO enzyme function in rat brain mitochondria.

Main Methods:

  • Utilized rat brain mitochondrial preparations.
  • Induced *OH production using ascorbic acid and varying concentrations of Fe2+.
  • Assessed the effects of *OH on MAO-A and MAO-B activities.

Main Results:

  • Hydroxyl radical generation significantly reduced both MAO-A (53-85%) and MAO-B (39-77%) activities.
  • A linear correlation was observed between *OH levels and the inhibition of both MAO-A and MAO-B.
  • The observed inhibition of MAO-A and MAO-B by *OH was irreversible.

Conclusions:

  • Hydroxyl radicals exert an irreversible inhibitory effect on MAO-A and MAO-B.
  • This inhibition may mitigate the contribution of MAO activity to brain oxidative stress under conditions of *OH overproduction.

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