Stimulation of group I metabotropic glutamate receptors evokes calcium signals and c-jun and c-fos gene expression in human T cells

Biochem Pharmacol. 2005 Jul 15;70(2):189-99. doi: 10.1016/j.bcp.2005.04.038.


To study if the activation of group I mGlu receptors in human T cells modifies intracellular Ca2+ concentration ([Ca2+](i)) and cell function, we measured [Ca2+](i) on cell suspensions (spectrofluorimetric method) or single cell (digital Ca2+ imaging system) using fura-2 as indicator. Early-inducible gene (c-jun and c-fos) expression was studied by reverse transcriptase-polymerase chain reaction assay as representative of Ca(2+)-sensitive gene expression. (1S,3R)-ACPD (100 microM), the selective mGlu receptor agonist, evoked a significant increase (34.1+/-4.9%) of [Ca2+](i), pharmacologically characterized as mediated by group I mGlu receptors, since both (S)-3,5-DHPG (100 microM), a selective group I mGlu receptor agonist and CHPG (1mM), the specific mGlu5 receptor agonist, reproduced the effects, that were abolished by AIDA (1mM), a selective group I mGlu receptor antagonist. (S)-3,5-DHPG-induced a rapid [Ca2+](i) rise (initial phase) followed by a slow decrease (second phase) to the baseline. Both extracellular Ca2+ and Ca2+ released from intracellular stores contribute to the [Ca2+](i) increase which depend on PLC activation. In a Ca(2+)-free buffer, the second phase rapidly return to the baseline; LaCl3 (1-10 microM), an inhibitor of extracellular Ca2+ influx, significantly reduced the second phase only; thapsigargin (1microM), by discharging intracellular Ca2+ stores, U 73122 (10 microM) and D609 (300 microM), by inhibiting PLC activity, prevented both phases. In our system, PTX pre-treatment increased (S)-3,5-DHPG effects, demonstrating that PXT-sensitive G(i/o) proteins are involved. Finally, specific stimulation of these receptors in Jurkat cells upregulates c-jun and c-fos gene expression, thus activating multiple downstream signalling regulating important T cell functions.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology
  • Genes, fos / drug effects
  • Genes, fos / physiology*
  • Genes, jun / drug effects
  • Genes, jun / physiology*
  • Glycine / analogs & derivatives*
  • Glycine / pharmacology
  • Humans
  • Jurkat Cells
  • Receptors, Metabotropic Glutamate / agonists
  • Receptors, Metabotropic Glutamate / metabolism*
  • Resorcinols / pharmacology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / metabolism*


  • Receptors, Metabotropic Glutamate
  • Resorcinols
  • metabotropic glutamate receptor type 1
  • 3,5-dihydroxyphenylglycine
  • Glycine