title: Depolarization exposes the voltage sensor of the sodium channels to the extracellular region.
abstract: Two domains of Na channels were mapped with site-specific antibodies raised in rabbit against synthetic peptides corresponding to a part of the voltage sensor of internal repeat 1-C1+ (amino acids 210-223) and to a region designated dipole (amino acids 1690-1699) of eel electroplax sodium channels. The antibodies bind to their respective domains in both purified and membrane-bound channels and immunoprecipitate the channels from eel electroplax and rat brain synaptosomes. Anti-C1+ depresses the action potential of rat sciatic nerve in a concentration-dependent way. It binds to the external side of rat brain synaptosomal vesicle, and its binding is potentiated by depolarization. Anti-dipole binds to the inner side of the vesicle, and the binding is inhibited by depolarization.
authors.affiliation: Department of Physiology and Biophysics, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
authors.forename: M
authors.initials: M
authors.lastname: Sammar
authors.forename: G
authors.initials: G
authors.lastname: Spira
authors.forename: H
authors.initials: H
authors.lastname: Meiri
mesh_terms: D000200:Action Potentials; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001665:Binding Sites; D004553:Electric Conductivity; D004557:Electric Organ / Q000737:chemistry* / Q000378:metabolism; D004593:Electrophorus; D004797:Enzyme-Linked Immunosorbent Assay; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D011817:Rabbits; D051381:Rats; D012530:Saxitoxin / Q000378:metabolism; D015222:Sodium Channels / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D013574:Synaptosomes / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000906:Antibodies; D010455:Peptides; D015222:Sodium Channels; D012530:Saxitoxin