Mitochondria are involved in the neurogenic neuroprotection conferred by stimulation of cerebellar fastigial nucleus

J Neurochem. 2005 Oct;95(1):221-9. doi: 10.1111/j.1471-4159.2005.03358.x.

Abstract

Activation of neural pathways originating in the cerebellar fastigial nucleus (FN) protects the brain from the deleterious effects of cerebral ischemia and excitotoxicity, a phenomenon termed central neurogenic neuroprotection. The neuroprotection is, in part, mediated by suppression of apoptosis. We sought to determine whether FN stimulation exerts its anti-apoptotic effect through mitochondrial mechanisms. Mitochondria were isolated from the cerebral cortex of rats in which the FN was stimulated for 1 h (100 microA; 1 s on/1 s off), 72 h earlier. Stimulation of the dentate nucleus (DN), a brain region that does not confer neuroprotection, served as control. Mitochondria isolated from FN-stimulated rats exhibited a marked increase in their ability to sequester Ca2+ and an increased resistance to Ca2+-induced membrane depolarization and depression in respiration. FN stimulation also leads to reduction in the release in cytochrome c, induced either by Ca2+ or the mitochondrial toxin mastoparan. Furthermore, in brain slices, FN stimulation reduced the staurosporine-induced insertion of the pro-apoptotic protein Bax into the mitochondria, a critical step in the mitochondrial mechanisms of apoptosis. Collectively, these results provide evidence that FN stimulation protects the mitochondria from dysfunction induced by Ca2+ loading, and inhibits mitochondrial pathways initiating apoptosis. These mitochondrial mechanisms are likely to play a role in the neuroprotection exerted by FN stimulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Calcium / metabolism
  • Calcium / pharmacology
  • Cerebellar Nuclei / physiology*
  • Cerebral Cortex / metabolism
  • Cerebral Cortex / physiology*
  • Cytochromes c / antagonists & inhibitors
  • Cytochromes c / metabolism
  • Electric Stimulation*
  • In Vitro Techniques
  • Intercellular Signaling Peptides and Proteins
  • Intracellular Membranes / physiology
  • Male
  • Membrane Potentials / physiology
  • Mitochondria / metabolism
  • Mitochondria / physiology*
  • Oxygen Consumption / drug effects
  • Peptides / pharmacology
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Wasp Venoms / pharmacology
  • bcl-2-Associated X Protein

Substances

  • Bax protein, rat
  • Intercellular Signaling Peptides and Proteins
  • Peptides
  • Proto-Oncogene Proteins c-bcl-2
  • Wasp Venoms
  • bcl-2-Associated X Protein
  • mastoparan
  • Cytochromes c
  • Calcium