Calcium influx via L-type voltage-gated channels mediates the delayed, elevated increases in steady-state c-fos mRNA levels in cerebellar granule cells exposed to excitotoxic levels of glutamate

Roger Griffiths, L Ritchie, K Lidwell, A Grieve, other 3

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

The altered kinetics of steady-state c-fos mRNA production in cultured cerebellar granule cells under excitotoxic conditions was investigated in neurons subjected to depolarising stimuli, namely, high KCI and L-glutamate (Glu), in which Ca2+ influx occurs by differing routes. Increases in intracellular-free calcium levels ([Ca2+](i)) stimulated by nontoxic or toxic levels of Glu were blocked by selective N-methyl-D-aspartate (NMDA) receptor antagonism; were blocked only partially by the L-type channel blocker, nifedipine; and were unaffected by alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)/kainate receptor antagonists. Glu-induced cell death was prevented only by NMDA receptor blockade, Exposure of cells to nontoxic levels of Glu resulted in a transient increase in c-fos mRNA levels, whereas an excitotoxic dose produced a delay in the appearance of c-fos mRNA but a subsequent, progressive, and sustained (>4 hr) increase. An excitotoxic dose of Glu in combination with either nifedipine or selective NMDA receptor antagonists resulted in the normal, transient increase of c-fos mRNA levels. Chronic exposure to 55 mM KCI caused no cytotoxicity, although it resulted in a delayed, elevated increase in c-fos mRNA levels that was unaffected by NMDA receptor blockade but reverted to the normal, transient profile of c-fos mRNA formation when it was coadministered with nifedipine, The KCl-induced increase in [Ca2+](i) levels was inhibited dramatically by nifedipine but was unaffected by any of the ionotropic Glu receptor antagonists. The results support the notion that the appearance of a delayed but elevated increase in steady-state c-fos mRNA levels following exposure to excitotoxic doses of Glu is mediated specifically by calcium influx via L-type voltage-gated channels, (C) 1998 Wiley-Liss, Inc.

Original languageEnglish
Pages (from-to)641-652
Number of pages12
JournalJournal of Neuroscience Research
Volume52
Publication statusPublished - 15 Jun 1998

Keywords

  • excitatory amino acid
  • excitotoxicity
  • c-fos mRNA
  • calcium
  • L-type calcium channels
  • cerebellar granule cells
  • METHYL-D-ASPARTATE
  • INDUCED NEURONAL DEATH
  • GENE-EXPRESSION
  • TRANSCRIPTION FACTORS
  • PRIMARY CULTURES
  • NERVOUS-SYSTEM
  • BRAIN
  • APOPTOSIS
  • NMDA
  • DIFFERENTIATION

Fingerprint

Dive into the research topics of 'Calcium influx via L-type voltage-gated channels mediates the delayed, elevated increases in steady-state c-fos mRNA levels in cerebellar granule cells exposed to excitotoxic levels of glutamate'. Together they form a unique fingerprint.

Cite this