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Membrane flow within the myelin sheath in IDPN neuropathy
Author(s) -
BLAUROCK A. E.,
CLAIR M. B. GENTER ST,
GRAHAM D. G.
Publication year - 1991
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.1365-2990.1991.tb00728.x
Subject(s) - axon , myelin , membrane , spinal cord , anatomy , biophysics , chemistry , ganglioside , myelin sheath , bilayer , ultrastructure , cerebrospinal fluid , lipid bilayer , biology , central nervous system , neuroscience , biochemistry
This Report describes some aspects of P, p'‐iminodipropionitrile (IDPN) neuropathy in rats as observed by ultrastructural methods and X‐ray diffraction. Light microscopy shows gross swelling of the axons in proximal lumbar spinal roots 8 days after intraperitoneal injection of IDPN. Mean axon cross‐sectional area and mean axon perimeter increased to 280% and 160% of their control values, respectively. At the same time, myelin membrane packing was not visibly disturbed. In addition, X‐ray diffraction patterns, recorded under physiological conditions, demonstrate that the myelin lipid bilayer thickness and widths of the aqueous spaces between bilayers did not change. Related observations are made on posterior tibial nerve (PNS myelin) and ventral spinal cord (CNS myelin). The various observations together are interpreted in terms of a fluid myelin membrane. It is proposed that the myelin membrane flows during axon swelling even though normal membrane‐membrane contacts are maintained within the sheath. Membrane flow and slippage between membranes are explained in terms of a molecular model of the myelin multilayer.