Relationship between L-glutamate-regulated intracellular Na+ dynamics and ATP hydrolysis in astrocytes

Pierre Magistretti, J. Y. Chatton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Glutamate uptake into astrocytes and the resulting increase in intracellular Na+ (Na+i) have been identified as a key signal coupling excitatory neuronal activity to increased glucose utilization. Arguments based mostly on mathematical modeling led to the conclusion that physiological concentrations of glutamate more than double astrocytic Na+/K+-ATPase activity, which should proportionally increase its ATP hydrolysis rate. This hypothesis was tested in the present study by fluorescence monitoring of free Mg2+ (Mg 2+i), a parameter that inversely correlates with ATP levels. Glutamate application measurably increased Mg2+i (i.e. decreased ATP), which was reversible after glutamate washout. Na +i and ATP changes were then directly compared by simultaneous Na+i and Mg2+ imaging. Glutamate increased both parameters with different rates and blocking the Na +/K+-ATPase during the glutamate-evoked Na +i response, resulted in a drop of Mg2+ i levels (i.e. increased ATP). Taken together, this study demonstrates the tight correlation between glutamate transport, Na+ homeostasis and ATP levels in astrocytes.

Original languageEnglish (US)
Pages (from-to)77-85
Number of pages9
JournalJournal of Neural Transmission
Volume112
Issue number1
DOIs
StatePublished - Jan 1 2005

Keywords

  • Energy metabolism
  • Fluorescence microscopy
  • Intracellular sodium

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health
  • Biological Psychiatry

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