Expression of alpha 4 and beta 2 nicotinic acetylcholine receptor subunit mRNA and localization of alpha-bungarotoxin binding proteins in the rat vestibular periphery.
In situ hybridization histochemistry was used to map the distribution of alpha 2, alpha 3, alpha 4, and beta 2 nAChR subunit mRNAs throughout the peripheral vestibular system of the rat. The alpha 4 and beta 2 nAChR subunit genes were co-expressed by populations of primary afferent neurons within Scarpa's ganglion, while there was no expression of the alpha 2, alpha 3, alpha 4, or beta 2 nAChR subunit genes by type I or type II vestibular hair cells. alpha-bungarotoxin binding to nAChRs in the vestibular end-organs was primarily limited to the afferent chalices surrounding type I hair cells and the basal aspect of type II hair cells. These data suggest that nAChRs composed of alpha 4 and beta 2 subunits are localized on afferent chalices innervating the type I vestibular hair cells and that the direct cholinergic efferent innervation of the type II vestibular hair cells utilizes nAChR composed of other subunits.
Wackym
P A
PA
Department of Otolaryngology, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
Popper
P
P
Lopez
I
I
Ishiyama
A
A
Micevych
P E
PE
D000344:Afferent Pathways / Q000378:metabolism; D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism*; D015870:Gene Expression; D017403:In Situ Hybridization; D008297:Male; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D011978:Receptors, Nicotinic / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D014722:Vestibule, Labyrinth / Q000737:chemistry*
D002038:Bungarotoxins; D012333:RNA, Messenger; D011978:Receptors, Nicotinic