Metabotropic glutamate receptor 1-mediated calcium mobilization in the neonatal hippocampal marginal zone

Eur J Neurosci. 2018 Dec;48(11):3344-3353. doi: 10.1111/ejn.14200. Epub 2018 Nov 1.

Abstract

The hippocampal marginal zone contains Cajal-Retzius (C-R) cells and participates in the regulation of cortical development. Two subtypes of group I metabotropic glutamate receptors (mGluRs), mGluR1 and mGluR5, are found in the central nervous system and are considered to regulate neuronal excitability. The release of Ca2+ from intracellular stores is thought to be a main consequence of activation of these receptor subtypes. In hippocampal C-R cells, the expression of mGluR1 has been showed using immunohistochemical techniques, but its function has not been elucidated. In this study, Ca2+ mobilization through mGluR1 activation was demonstrated in the neonatal rat hippocampus. In marginal zone C-R cells, intracellular Ca2+ elevation was detected by fluorescence imaging after the application of a group I mGluR-specific agonist. This response was prevented by application of an mGluR1 antagonist but was not changed by application of an mGluR5 antagonist. The intracellular Ca2+ elevation induced by mGluR1 activation was still observed in Ca2+ -free perfusate, indicating the release of Ca2+ from intracellular stores. γ-Aminobutyric acid and ionotropic glutamate receptor-mediated intracellular Ca2+ elevation was also detected in mGluR1-possessing neurons, although the former was much smaller than that mediated by mGluR1. These results indicate that mGluR1 is functionally expressed in C-R cells in the neonatal marginal zone and regulates cell function through the elevation of intracellular Ca2+ .

Keywords: Cajal-Retzius cell; acute slice; calcium imaging; rat; γ-aminobutyric acid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Glutamic Acid / metabolism
  • Hippocampus / metabolism*
  • Male
  • Neurons / metabolism*
  • Rats, Wistar
  • Receptor, Metabotropic Glutamate 5 / metabolism
  • Receptors, Metabotropic Glutamate / metabolism*
  • Signal Transduction / physiology
  • Temporal Lobe / metabolism
  • gamma-Aminobutyric Acid / metabolism

Substances

  • Receptor, Metabotropic Glutamate 5
  • Receptors, Metabotropic Glutamate
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Calcium