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COPPER BINDING AT PNS NODES OF RANVIER DURING DEMYELINATION AND REMYELINATION IN THE PERINEURIAL WINDOW
Author(s) -
BAECQUE CECILE DE,
RAINE C. S.,
SPENCER P. S.
Publication year - 1976
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.1976.tb00520.x
Subject(s) - node of ranvier , remyelination , myelin , axon , myelin sheath , schwann cell , chemistry , nodal , peripheral nervous system , biophysics , anatomy , pathology , neuroscience , biology , central nervous system , medicine
Nodes of Ranvier of peripheral nerves are associated with mucopolysaccharide which is capable of binding a wide variety of cations. The present study has determined the changes in the binding properties of the node of Ranvier during demyelination and remyelination in the perineurial window. The location of copper ion binding, visualized as a dense copper ferrocyanide precipitate, was studied in teased fibres from 60 rat peroneal nerves with single perineurial windows and from 8 normal nerves. In normal nerves, precipitate was present over the nodal axon and at the borders of the paranodal axon. Before demyelination, severely beaded fibres sited within the perineurial window displayed a reduction or a loss of nodal precipitate. During the period of myelin phagocytosis and demyelination, precipitate was absent throughout the denuded axon but present at adjacent, uninvolved nodes. At the commencement of remyelination, precipitate appeared at the newlycreated nodal and paranodal regions and at interfaces between preserved and remyelinating internodes. The density increased with myelin thickening. These findings indicate: (1) severely beaded regions lose their normal binding property before undergoing demyelination, (2) demyelinated regions do not bind copper ions, (3) remyelinating fibres bind copper ions at newly‐created nodes and (4) Schwann cells are responsible for the production of nodal mucopolysaccharides.