The sensitivity of the myelin sheath, particularly the Schwann cell-axolemmal junction, to lowered calcium levels in cultured sensory ganglia

William F. Blank, Mary B Bunge, Richard P. Bunge

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Light and electron microscopic observations were made on myelinated cultures of sensory ganglia maintained for 2-12 days on media with low calcium (0.025-0.050 mM) or normal calcium (1.5-2.0 mM) levels. After 18 h at low calcium levels, lengthening of the node of Ranvier and apparent fluid accumulation between the axon and the myelin sheath were observed in the light microscope. Electron microscopic observations indicated that these changes began with an accumulation of fluid between the Schwann cell terminal loops in the paranodal region, shrinkage and stretching of the terminal loops, and eventual breaking of the junction between the loops and the axolemma. Accompanying these changes was substantial fluid accumulation in the periaxonal space along much of the internode. These changes were found to be slowly reversible upon return to media with normal calcium levels. These observations are discussed in relation to the known properties of various types of intercellular junctions and the physiological properties of the myelinated nerve fiber. It is suggested that the unique structural characteristics of the Schwann cell-axolemmal junction in the paranodal region may relate to the presumed functional requirements of saltatory conduction, i.e., adhesiveness for the maintenance of myelin form and/or sealing of the periaxonal space from the general extracellular space, but without the establishment of low resistance channels between Schwann cell and axon.

Original languageEnglish
Pages (from-to)503-518
Number of pages16
JournalBrain Research
Volume67
Issue number3
DOIs
StatePublished - Mar 8 1974
Externally publishedYes

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Sensory Ganglia
Intercellular Junctions
Schwann Cells
Myelin Sheath
Calcium
Axons
Ranvier's Nodes
Electrons
Light
Myelinated Nerve Fibers
Adhesiveness
Extracellular Space
Maintenance

ASJC Scopus subject areas

  • Developmental Biology
  • Molecular Biology
  • Clinical Neurology
  • Neuroscience(all)

Cite this

The sensitivity of the myelin sheath, particularly the Schwann cell-axolemmal junction, to lowered calcium levels in cultured sensory ganglia. / Blank, William F.; Bunge, Mary B; Bunge, Richard P.

In: Brain Research, Vol. 67, No. 3, 08.03.1974, p. 503-518.

Research output: Contribution to journalArticle

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