Development of a glial network in the olfactory nerve: role of calcium and neuronal activity

Neuron Glia Biol. 2010 Nov;6(4):245-61. doi: 10.1017/S1740925X11000081. Epub 2011 Sep 21.

Abstract

In adult olfactory nerves of mammals and moths, a network of glial cells ensheathes small bundles of olfactory receptor axons. In the developing antennal nerve (AN) of the moth Manduca sexta, the axons of olfactory receptor neurons (ORNs) migrate from the olfactory sensory epithelium toward the antennal lobe. Here we explore developmental interactions between ORN axons and AN glial cells. During early stages in AN glial-cell migration, glial cells are highly dye coupled, dividing glia are readily found in the nerve and AN glial cells label strongly for glutamine synthetase. By the end of this period, dye-coupling is rare, glial proliferation has ceased, glutamine synthetase labeling is absent, and glial processes have begun to extend to enwrap bundles of axons, a process that continues throughout the remainder of metamorphic development. Whole-cell and perforated-patch recordings in vivo from AN glia at different stages of network formation revealed two potassium currents and an R-like calcium current. Chronic in vivo exposure to the R-type channel blocker SNX-482 halted or greatly reduced AN glial migration. Chronically blocking spontaneous Na-dependent activity by injection of tetrodotoxin reduced the glial calcium current implicating an activity-dependent interaction between ORNs and glial cells in the development of glial calcium currents.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biophysics
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Cell Communication / drug effects
  • Cell Communication / physiology
  • Cells, Cultured
  • Electric Stimulation
  • Gap Junctions / ultrastructure
  • Glutamate-Ammonia Ligase / metabolism
  • Histones / metabolism
  • Manduca / anatomy & histology*
  • Manduca / growth & development
  • Membrane Potentials / drug effects
  • Microscopy, Electron / methods
  • Nerve Net / physiology
  • Neuroglia / physiology*
  • Neuroglia / ultrastructure
  • Olfactory Nerve / cytology*
  • Olfactory Nerve / growth & development*
  • Olfactory Receptor Neurons / drug effects
  • Olfactory Receptor Neurons / physiology*
  • Organic Chemicals / metabolism
  • Patch-Clamp Techniques
  • Sodium Channel Blockers
  • Spider Venoms / pharmacology
  • Tetrodotoxin / pharmacology

Substances

  • Calcium Channel Blockers
  • Histones
  • Organic Chemicals
  • SNX 482
  • SYTO 13
  • Sodium Channel Blockers
  • Spider Venoms
  • Tetrodotoxin
  • Glutamate-Ammonia Ligase
  • Calcium