Gangliosides normalize distorted single-cell intracellular free Ca2+ dynamics after toxic doses of glutamate in cerebellar granule cells

Gabriel A. De Erausquin, Hari Manev, Alessandro Guidotti, Erminio Costa, Gary Brooker

Research output: Contribution to journalArticle

111 Scopus citations

Abstract

Glutamate-induced delayed neurotoxicity after abusive and paroxismal activation of its receptors has been proposed to depend upon a sustained increase in intracellular free Ca2+([Ca2+]i). To elucidate the temporal and causal relationship between glutamate-induced changes in [Ca2+]i and neuronal death, we simultaneously studied the dynamics of [Ca2+]i changes in single neurons with the acetoxymethyl ester of fura-2 and the cell viability by imaging the nuclear penetration of propidium iodide. The main difference between toxic (50 μM) and nontoxic (5 μM) doses of glutamate is the lack of regulation in [Ca2+]i 20 min after glutamate is removed. This protracted rise in [Ca2+]i in a single cell is correlated with (r = 0.87, P < 0.01, Spearman's test), and consequently predictive of, the time of appearance of neuronal death, as measured by propidium iodide fluorescence. In addition, the glutamate receptor antagonists dibenzocyclohepteneimine (MK-801) and 3,3-(2-carboxypiperazine-4-yl)propyl 1-phosphate reduce the acute increase of [Ca2+]i induced by glutamate but fail to revert the protracted increase of [Ca2+]i elicited by toxic doses of glutamate. In contrast, the ganglioside GM1 and the semisynthetic lysoGM1 with N-acetylsphingosine (LIGA-4) and lysoGM1 with N-dichloroacetylsphingosine (LIGA-20) failed to change the immediate rise of [Ca2+]i elicited by glutamate but prevented the protracted increase in [Ca2+]i after toxic doses of glutamate. Voltage-dependent Ca2+ channel blockers (nifedipine, etc.) did not change the initial or protracted responses to glutamate.

Original languageEnglish (US)
Pages (from-to)8017-8021
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume87
Issue number20
DOIs
StatePublished - 1990
Externally publishedYes

Keywords

  • Calcium homeostasis
  • Double labeling fluorescence microscopy
  • Fura-2 imaging
  • Neurotoxicity

ASJC Scopus subject areas

  • General

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