NMDA (NMDAR1) AND AMPA-TYPE (GLUR2 3) RECEPTOR SUBUNITS ARE EXPRESSEDIN THE INNER-EAR/

USING receptor subunit-specific antibodies, the cellular localization of NMDA and AMPA type glutamate receptor subunits was studied within t he rodent (rat, guinea pig) and non-human primate (monkey) inner ear. In the spiral and vestibular ganglion, almost all cells were immunorea ctive for the NMDAR1 subunit and the AMPA type receptor subunit GluR2/ 3. This indicates that both NMDA and non-NMDA type glutamate receptors may be co-distributed in the primary afferent neuronal components, an d are possibly involved in neurotransmission in the primary auditory a nd vestibular systems. This study also indicated the possible localiza tions of glutamate receptors in the nonneuronal cells in the inner ear , suggesting that some nonneuronal cells may also have the ability to mediate glutamate signalling.