Abstract
We report the isolation and functional characterization of a member of the nicotinic acetylcholine receptor subunit gene family, alpha 9. Xenopus oocytes injected with alpha 9 cRNA express a homomeric receptor-channel complex that is activated by acetylcholine. The alpha 9 receptor displays an unusual mixed nicotinic-muscarinic pharmacological profile. The unique properties of the alpha 9 receptor-channel complex closely match those described for the cholinergic receptor present in vertebrate cochlear hair cells. In situ hybridization studies reveal a restricted pattern of alpha 9 gene expression that includes the outer hair cells of the rat cochlea. Our results suggest that the alpha 9 receptor is involved in the cholinergic efferent innervation of cochlear hair cells and thus may modulate the encoding of auditory stimuli.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Atropine / pharmacology
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Base Sequence
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Brain / cytology
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Brain / embryology
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Brain / metabolism
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Bungarotoxins / pharmacology
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Chickens
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Evoked Potentials / drug effects
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Gene Expression*
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Gene Library
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Gestational Age
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Hair Cells, Auditory / cytology
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Hair Cells, Auditory / metabolism
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Hair Cells, Auditory / physiology*
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In Situ Hybridization
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Macromolecular Substances
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Molecular Sequence Data
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Multigene Family*
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Muscarine / pharmacology
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Nicotine / pharmacology
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Oxotremorine / pharmacology
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Polymerase Chain Reaction
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Rats
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Rats, Sprague-Dawley
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Receptors, Nicotinic / biosynthesis*
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Receptors, Nicotinic / drug effects
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Receptors, Nicotinic / physiology
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Sequence Homology, Amino Acid
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Strychnine / pharmacology
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Transcription, Genetic
Substances
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Bungarotoxins
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Macromolecular Substances
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Receptors, Nicotinic
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Oxotremorine
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Nicotine
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Atropine
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Muscarine
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Strychnine