Expression of γ‐Aminobutyric Acid_A Receptor Subunits in the Vestibular System

Abstract

These results give the most direct evidence to date that GABAA receptors composed of the detected subunits are expressed in the mammalian vestibular system, giving new support to previous investigations implicating GABA as a vestibular neurotransmitter.

γ‐Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

“…However, localization of GABA transaminase, an enzyme responsible for GABA degradation, is less clear; the enzyme has been found in some hair cells (types I and II) and calyces of the guinea pig (López et al, 1992), but only in fibers thought to be afferent processes in chicken (Usami et al, 1989). Similarly, there is some evidence supporting both GABA A (Kitahara et al, 1994;Foster et al, 1995;Rezaee et al, 1999) and GABA B (Lapeyre et al, 1993) receptor subunit expression in the vestibular periphery. None of these investigations addresses the possibility of glutamate and GABA coexpression, and none demonstrates regional diversity in transmitter phenotype.…”