Magnesium ions inhibit the stimulation of inositol phospholipid hydrolysis by endogenous excitatory amino acids in primary cultures of cerebellar granule cells

F. Nicoletti, J. T. Wroblewski, E. Costa

Research output: Contribution to journalArticle

Abstract

Omission of Mg2+ from the incubation buffer results in a six- to eightfold increase in [3H]inositol-1-phosphate ([3H]Ins-1-P) accumulation in primary cultures of cerebellar granule cells at 7-9 days in vitro. This increase is reversed by low concentrations of 2-amino-5-phosphonovalerate (APV), a result indicating that the absence of Mg2+ facilitates the activation of a specific receptor by the endogenous excitatory amino acids (presumably L-glutamate and L-aspartate) released from the granule cells. The absence of Mg2+ also potentiates the action of exogenously applied N-methyl-D-aspartate (NMDA), L-glutamate, L-aspartate, and kainate. In contrast, the action of quisqualate is virtually unaffected by Mg2+ and is resistant to APV inhibition. Addition of the depolarization agent veratridine enhances the accumulation of [3H]Ins-1-P also in Mg2+-containing buffer. The action of veratridine is antagonized by APV, a result suggesting that, under depolarized conditions, the NMDA receptor can be activated by the endogenously released excitatory amino acids, despite the presence of Mg2+. Accordingly, in the presence of Mg2+, veratridine potentiates the action of exogenously applied NMDA but does not facilitate the action of quisqualate.

Original languageEnglish
Pages (from-to)967-973
Number of pages7
JournalJournal of Neurochemistry
Volume48
Issue number3
Publication statusPublished - 1987

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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