title: Voltage-gated sodium channel expression in rat spiral ganglion neurons.
abstract: The spiral ganglion neurons (SGN) provide the afferent innervation of the hair cells in the organ of Corti and relay auditory information from the inner ear to the brain. Voltage-gated sodium channels (Na(V)) initiate and propagate action potentials that encode this sensory information but little is known regarding the subtypes expressed in these cells. We have used RT-PCR and immunohistochemistry to study the compliment and anatomical distribution of Na(V) channels in rodent SGN. Na(V)1.1, Na(V)1.6 and Na(V)1.7 were all detected at the mRNA level. Fluorescence or streptavidin-horseradish peroxidase immunohistochemistry extended these findings, demonstrating predominant localisation of Na(V)1.6 and Na(V)1.7 on SGN cell bodies and Na(V)1.1 on axonal processes. Dual labelling with peripherin demonstrated higher Na(V)1.6 and Na(V)1.7 expression on Type I rather than Type II neurons. These results provide evidence for selective expression and variations in the distribution of VGSC in the rodent SGN, which may guide further studies into afferent function in the auditory pathway and therapeutic approaches for diseases such as hearing loss and tinnitus.
authors.affiliation: Department of Cell Physiology and Pharmacology, University of Leicester, University Road, Leicester LE19HN, UK. agf4@le.ac.uk
authors.forename: A G
authors.initials: AG
authors.lastname: Fryatt
authors.forename: C
authors.initials: C
authors.lastname: Vial
authors.forename: M
authors.initials: M
authors.lastname: Mulheran
authors.forename: M J
authors.initials: MJ
authors.lastname: Gunthorpe
authors.forename: B D
authors.initials: BD
authors.lastname: Grubb
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D064531:Peripherins; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D013136:Spiral Ganglion / Q000166:cytology*
chemical_list: D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D062550:NAV1.1 Voltage-Gated Sodium Channel; D062557:NAV1.6 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D064531:Peripherins; D020033:Protein Isoforms; D021122:Protein Subunits; D012333:RNA, Messenger; C568250:Scn1a protein, rat; C507811:Scn8a protein, rat; C503480:Scn9a protein, rat; D015222:Sodium Channels