Excitotoxic injury to mitochondria isolated from cultured neurons

Yulia E. Kushnareva, Sandra E. Wiley, Manus Ward, Alexander Y. Andreyev, Anne N. Murphy*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    59 Scopus citations

    Abstract

    Neuronal death in response to excitotoxic levels of glutamate is dependent upon mitochondrial Ca 2+ accumulation and is associated with a drop in ATP levels and a loss in ionic homeostasis. Yet the mapping of temporal events in mitochondria subsequent to Ca 2+ sequestration is incomplete. By isolating mitochondria from primary cultures, we discovered that glutamate treatment of cortical neurons for 10 min caused 44% inhibition of ADP-stimulated respiration, whereas the maximal rate of electron transport (uncoupler-stimulated respiration) was inhibited by ∼10%. The Ca 2+ load in mitochondria from glutamate-treated neurons was estimated to be 167 ± 19 nmol/mg protein. The glutamate-induced Ca 2+ load was less than the maximal Ca 2+ uptake capacity of the mitochondria determined in vitro (363 ± 35 nmol/mg protein). Comparatively, mitochondria isolated from cerebellar granule cells demonstrated a higher Ca 2+ uptake capacity (686 ± 71 nmol/mg protein) than the cortical mitochondria, and the glutamate-induced load of Ca 2+ was a smaller percentage of the maximal Ca 2+ uptake capacity. Thus, this study indicated that Ca 2+ -induced impairment of mitochondrial ATP production is an early event in the excitotoxic cascade that may contribute to decreased cellular ATP and loss of ionic homeostasis that precede commitment to neuronal death.

    Original languageEnglish (US)
    Pages (from-to)28894-28902
    Number of pages9
    JournalJournal of Biological Chemistry
    Volume280
    Issue number32
    DOIs
    StatePublished - Aug 12 2005

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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