Expression of GABAA receptor gamma 1 and gamma 2 subunits in the peripheral vestibular system of the rat.

The distribution of GABAA receptor gamma 1 and gamma 2 subunits in the rat vestibular ganglion cells and end-organs was examined by using immunohistochemical techniques. Both gamma 1 and gamma 2 subunit-like immunoreactivities were observed in most vestibular ganglion cell bodies and peripheral terminal endings in the vestibular sensory epithelia. These results indicate that GABAA receptors are expressed in the vestibular afferent terminal endings and therefore suggest that GABA in addition to glutamate is a neurotransmitter which effects on vestibular afferents.