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Updated: Jul 5, 2026

Multi-photon Intracellular Sodium Imaging Combined with UV-mediated Focal Uncaging of Glutamate in CA1 Pyramidal Neurons
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Partial inhibition of complex I activity increases Ca-independent glutamate release rates from depolarized

Seán M Kilbride1, Jayne E Telford, Keith F Tipton

  • 1School of Biochemistry and Immunology & Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland.

Journal of Neurochemistry
|May 1, 2008
PubMed

Insights

Partial inhibition of mitochondrial complex I (NADH:ubiquinone oxidoreductase) increases glutamate release from nerve terminals. This dysfunction, linked to neurodegenerative diseases, disrupts cellular energy and membrane potential.

Area of Science:

  • Neuroscience
  • Biochemistry
  • Cell Biology

Background:

  • Mitochondrial dysfunction, particularly complex I (NADH:ubiquinone oxidoreductase) reduction, is implicated in Parkinson's disease pathogenesis.
  • Complex I activity is reduced in the substantia nigra of Parkinson's disease patients.

Purpose of the Study:

  • To investigate the impact of partial complex I inhibition on glutamate release from rat brain synaptosomes.
  • To explore the relationship between complex I activity, ATP levels, and mitochondrial membrane potential.

Main Methods:

  • Partial inhibition of complex I using rotenone in isolated rat brain synaptosomes.
  • Measurement of Ca(2+)-independent glutamate release upon depolarization with 4-aminopyridine or KCl.
  • Assessment of ATP levels and mitochondrial membrane potential (Deltapsi(m)).

Main Results:

  • Partial inhibition (40%) of complex I activity significantly increased Ca(2+)-independent glutamate release.
  • Peak glutamate release occurred between 60-90% complex I inhibition.
  • Increased glutamate release correlated with decreased ATP levels and a collapse in mitochondrial membrane potential.

Conclusions:

  • Partial inhibition of mitochondrial complex I is sufficient to trigger glutamate release from presynaptic terminals.
  • These findings suggest a role for mitochondrial dysfunction in excitotoxicity and neurodegeneration.
  • The study highlights the link between impaired mitochondrial function and neurotransmitter release in neurological disorders.

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