Ca(2+) signaling evoked by activation of Na(+) channels and Na(+)/Ca(2+) exchangers is required for GABA-induced NG2 cell migration

J Cell Biol. 2009 Jul 13;186(1):113-28. doi: 10.1083/jcb.200811071.

Abstract

NG2 cells originate from various brain regions and migrate to their destinations during early development. These cells express voltage-gated Na(+) channels but fail to produce typical action potentials. The physiological role of Na(+) channels in these cells is unclear. We found that GABA induces membrane depolarization and Ca(2+) elevation in NG2 cells, a process requiring activation of GABA(A) receptors, Na(+) channels, and Na(+)/Ca(2+) exchangers (NCXs), but not Ca(2+) channels. We have identified a persistent Na(+) current in these cells that may underlie the GABA-induced pathway of prolonged Na(+) elevation, which in turn triggers Ca(2+) influx via NCXs. This unique Ca(2+) signaling pathway is further shown to be involved in the migration of NG2 cells. Thus, GABAergic signaling mediated by sequential activation of GABA(A) receptors, noninactivating Na(+) channels, and NCXs may play an important role in the development and function of NG2 glial cells in the brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Signaling / drug effects*
  • Cell Movement / drug effects*
  • Cells, Cultured
  • Down-Regulation / drug effects
  • Gramicidin / pharmacology
  • Hippocampus / cytology
  • Ion Channel Gating / drug effects*
  • Membrane Potentials / drug effects
  • RNA, Small Interfering / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, GABA-A / metabolism
  • Sodium / metabolism
  • Sodium Channels / metabolism*
  • Sodium-Calcium Exchanger / metabolism*
  • gamma-Aminobutyric Acid / pharmacology*

Substances

  • RNA, Small Interfering
  • Receptors, GABA-A
  • Sodium Channels
  • Sodium-Calcium Exchanger
  • Gramicidin
  • gamma-Aminobutyric Acid
  • Sodium