Satellite glia cells in dorsal root ganglia express functional NMDA receptors

Neuroscience. 2013 Jun 14;240:135-46. doi: 10.1016/j.neuroscience.2013.02.031. Epub 2013 Feb 26.

Abstract

Satellite glia cells (SGCs), within the dorsal root ganglia (DRG), surround the somata of most sensory neurons. SGCs have been shown to interact with sensory neurons and appear to be involved in the processing of afferent information. We found that in rat DRG various N-methyl-D-aspartate receptor (NMDAr) subunits were expressed in SGCs in intact ganglia and in vitro. In culture, when SGCs were exposed to brief pulses of NMDA they evoked transient increases in cytoplasmic calcium that were inhibited by specific NMDA blockers (MK-801, AP5) while they were Mg²⁺ insensitive indicating that SGCs express functional NMDAr. The percentage of NMDA responsive SGCs was similar in mixed- (SGCs plus neurons) and SGC-enriched cultures. The pattern of the magnitude changes of the NMDA-evoked response was similar in SGCs and DRG neurons when they were in close proximity, suggesting that the NMDA response of SGCs and DRG neurons is modulated by their interactions. Treating the cultures with nerve growth factor, and/or prostaglandin E₂ did not alter the percentage of SGCs that responded to NMDA. Since glutamate appears to be released within the DRG, the detection of functional NMDAr in SGCs suggests that their NMDAr activity could contribute to the interactions between neurons and SGCs. In summary we demonstrated for the first time that SGCs express functional NMDAr.

MeSH terms

  • Action Potentials / drug effects
  • Animals
  • Calcium / metabolism
  • Cells, Cultured
  • Dinoprostone / pharmacology
  • Dose-Response Relationship, Drug
  • Excitatory Amino Acid Agonists / pharmacology
  • Ganglia, Spinal / cytology*
  • Glutamate-Ammonia Ligase / metabolism
  • Male
  • N-Methylaspartate / pharmacology
  • Nerve Growth Factor / pharmacology
  • Nerve Tissue Proteins / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Satellite Cells, Perineuronal / drug effects
  • Satellite Cells, Perineuronal / metabolism*

Substances

  • Excitatory Amino Acid Agonists
  • Nerve Tissue Proteins
  • Receptors, N-Methyl-D-Aspartate
  • N-Methylaspartate
  • Nerve Growth Factor
  • Glutamate-Ammonia Ligase
  • Dinoprostone
  • Calcium