title: Spatial and temporal expression patterns of nicotinic acetylcholine α9 and α10 subunits in the embryonic and early postnatal inner ear.
abstract: The expression and function of nicotinic receptor subunits (nAChRs) in the inner ear before the onset of hearing is not well understood. We investigated the mRNA expression of the α9 and α10 nAChR subunits in sensory hair cells of the embryonic and postnatal rat inner ear. We mapped their spatial and temporal expression in cochlear and vestibular hair cells using qPCR, [35S] labeled cRNA in situ hybridization, and α-bungarotoxin (α-Bgt) to label the presumptive membrane-bound receptor on cochlear hair cells. The results suggest that (1) the mRNA expression of the α9 subunit precedes expression of the α10 subunit in both cochlear and vestibular hair cells, (2) the mRNA expression of both the α9 and α10 subunits occurs earlier in the vestibular system than in the cochlea, (3) the mRNA expression of both subunits is required for the assembled receptor complexes, and (4) the presumptive assembled receptor, at least in the cochlea, is associated with synapse formation and the onset of function.
authors.affiliation: Department of Integrative Biology and Physiology and the Brain Research Institute, University of California, Los Angeles, CA 90095-7239, USA. dd.simmons@ucla.edu
authors.forename: D D
authors.initials: DD
authors.lastname: Simmons
authors.forename: B J
authors.initials: BJ
authors.lastname: Morley
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D007758:Ear, Inner / Q000196:embryology* / Q000254:growth & development* / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006198:Hair Cells, Auditory / Q000378:metabolism*; D018069:Hair Cells, Vestibular / Q000378:metabolism*; D011247:Pregnancy; D021122:Protein Subunits / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000235:genetics; D011978:Receptors, Nicotinic / Q000096:biosynthesis / Q000235:genetics*
chemical_list: C470699:Chrna10 protein, rat; D021122:Protein Subunits; D012333:RNA, Messenger; D011978:Receptors, Nicotinic; C443079:nAChR alpha9