title: Distinct localization of peripheral and central types of choline acetyltransferase in the rat cochlea.
abstract: We previously discovered a splice variant of choline acetyltransferase (ChAT) mRNA, and designated the variant protein pChAT because of its preferential expression in peripheral neuronal structures. In this study, we examined the immunohistochemical localization of pChAT in rat cochlea and compared the distribution pattern to those of common ChAT (cChAT) and acetylcholinesterase. Some neuronal cell bodies and fibers in the spiral ganglia showed immunoreactivity for pChAT, predominantly the small spiral ganglion cells, indicating outer hair cell type II neurons. In contrast, cChAT- and acetylcholinesterase-positive structures were localized to fibers and not apparent in ganglion cells. After ablation of the cochlear nuclei, many pChAT-positive cochlear nerve fibers became clearly visible, whereas fibers immunopositive for cChAT and acetylcholine esterase disappeared. These results suggested that pChAT and cChAT are localized in different systems of the rat cochlea; pChAT in the afferent and cChAT in the efferent structures.
authors.affiliation: Molecular Neuroscience Research Center, Shiga University of Medical Science ; Department of Otorhinolaryngology, Shiga University of Medical Science.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kitanishi
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Aimi
authors.forename: Hiroya
authors.initials: H
authors.lastname: Kitano
authors.forename: Mikio
authors.initials: M
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Saito
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Ikuo
authors.initials: I
authors.lastname: Tooyama
keywords: acetylcholine; choline acetyltransferase; cholinergic neurons; cochlear nervous system; spiral ganglion