Expression of inducible nitric oxide synthase in the cochlea following immune response in the endolymphatic sac of guinea pigs.

Immunohistochemical study for inducible nitric oxide synthase (iNOS or NOS II) in the cochlea of guinea pigs was performed after the injection of keyhole limpet hemocyanin (KLH) into the endolymphatic sac. Morphological changes were observed in the cochlea of all animals after the injection of KLH. Increased iNOS expression was detected in the lateral wall, organ of Corti and ganglion cells. It is known that high levels of nitric oxide can lead to inner ear dysfunction. Our results suggest that iNOS may mediate the inner ear disturbance as seen in endolymphatic hydrops.