Excitotoxic injury to mitochondria isolated from cultured neurons

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

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    66 Scopus citations


    Neuronal death in response to excitotoxic levels of glutamate is dependent upon mitochondrial Ca2+ 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 Ca2+ 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 Ca2+ load was less than the maximal Ca2+ uptake capacity of the mitochondria determined in vitro (363 ± 35 nmol/mg protein). Comparatively, mitochondria isolated from cerebellar granule cells demonstrated a higher Ca2+ uptake capacity (686 ± 71 nmol/mg protein) than the cortical mitochondria, and the glutamate-induced load of Ca2+ was a smaller percentage of the maximal Ca2+ uptake capacity. Thus, this study indicated that Ca2+-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
    Issue number32
    StatePublished - Aug 12 2005

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology


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