title: Nodal sodium channel domain integrity depends on the conformation of the paranodal junction, not on the presence of transverse bands.
abstract: Our understanding of the role that axoglial interactions play in node of Ranvier formation and maintenance remains incomplete. Previous studies of CNS myelinated fibers of CGT-null mice showed abnormalities in the arrangement of paranodal myelin loops and absence of a conspicuous component of the paranodal junction, the ridge-like intercellular transverse bands. Axolemmal sodium channel domains were largely preserved at nodes of Ranvier but displayed some abnormalities in form. Using a combination of freeze-fracture and immunocytochemical methods, we have found additional evidence documenting abnormalities in the size, shape, and location of axolemmal sodium channel clusters in CGT-null mice as well as evidence that these nodal abnormalities are complementary to the organization of paranodal myelin loops, despite the absence of transverse bands. We conclude that the differentiated form of the nodal axolemma and the distribution of axolemmal sodium channels depend on the conformation of paranodal axoglial contacts but not on the presence of transverse bands at the sites of contact.
authors.affiliation: Department Physiology and Neuroscience and Rusk Institute, New York University School of Medicine, New York, New York 10016, USA. ronsenj03@popmail.med.nyu.edu
authors.forename: Jack
authors.initials: J
authors.lastname: Rosenbluth
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Dupree
authors.forename: Brian
authors.initials: B
authors.lastname: Popko
mesh_terms: D000818:Animals; D005260:Female; D005614:Freeze Fracturing; D005700:Galactosyltransferases / Q000235:genetics*; D051147:Ganglioside Galactosyltransferase; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008818:Mice, Neurologic Mutants; D018613:Microscopy, Confocal; D009413:Nerve Fibers, Myelinated / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D011901:Ranvier's Nodes / Q000737:chemistry* / Q000473:pathology* / Q000648:ultrastructure; D015222:Sodium Channels / Q000032:analysis*; D013116:Spinal Cord / Q000473:pathology
chemical_list: D015222:Sodium Channels; D005700:Galactosyltransferases; C511214:Ugt8a protein, mouse; D051147:Ganglioside Galactosyltransferase