Alpha 9: an acetylcholine receptor with novel pharmacological properties expressed in rat cochlear hair cells.
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.
Salk Institute for Biological Studies, La Jolla, California 92037.
A B
AB
Elgoyhen
D S
DS
Johnson
J
J
Boulter
D E
DE
Vetter
S
S
Heinemann
D000595:Amino Acid Sequence; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001483:Base Sequence; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D002038:Bungarotoxins / Q000494:pharmacology; D002645:Chickens; D005071:Evoked Potentials / Q000187:drug effects; D015870:Gene Expression; D015723:Gene Library; D005865:Gestational Age; D006198:Hair Cells, Auditory / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D017403:In Situ Hybridization; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D005810:Multigene Family; D009116:Muscarine / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D010095:Oxotremorine / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000096:biosynthesis* / Q000187:drug effects / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013331:Strychnine / Q000494:pharmacology; D014158:Transcription, Genetic
D002038:Bungarotoxins; D046911:Macromolecular Substances; D011978:Receptors, Nicotinic; D010095:Oxotremorine; D009538:Nicotine; D001285:Atropine; D009116:Muscarine; D013331:Strychnine