title: Initiation of sodium channel clustering at the node of Ranvier in the mouse optic nerve.
abstract: Ion fluxes in mammalian myelinated axons are restricted to the nodes of Ranvier, where, in particular, voltage-gated Na+ channels are clustered at a high density. The node of Ranvier is separated from the internode by two distinct domains of the axolemma, the paranode and the juxtaparanode. Each axonal domain is characterized by the presence of a specific protein complex. Although oligodendrocytes and/or myelin membranes are believed to play some instructive roles in the organization of axonal domains, the mechanisms leading to their localized distribution are not well understood. In this paper we focused on the involvement of myelin sheaths in this domain organization and examined the distribution of axonal components in the optic nerves of wild type, hypomyelinatingjimpy mice and demyelinating PLP transgenic mice. The results showed that the clustering of Na+ channels does not require junction-like structures to be formed between the glial processes and axons, but requires mature oligodendrocytes to be present in close vicinity.
authors.affiliation: Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ikenaka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Tetshushi
authors.initials: T
authors.lastname: Kagawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Baba
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015640:Ion Channel Gating; D051379:Mice; D008813:Mice, Inbred ICR; D009900:Optic Nerve / Q000378:metabolism*; D011901:Ranvier's Nodes / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism*
chemical_list: D015222:Sodium Channels