Expression of inducible nitric oxide synthase (iNOS/NOS II) in the hydropic cochlea of guinea pigs

Immunohistochemical investigations of the guinea pig cochlea, using a speci fic antibody to the inducible isoform of NO synthase (iNOS/NOS II), have be en performed 3 weeks after closure of the right endolymphatic duct (n = 7). Endolymphatic hydrops, the morphological substrate of Meniere's disease, b ecame evident by distension of the Reissner's membrane. iNOS expression cou ld be noted in endothelium, spiral ganglion cells, in nerve fibers, in supp orting cells of the organ of Corti and cells of the spiral ligament. Tempor al bones of non-operated controls (n = 6) as well as of sham-operated anima ls (n = 3) did not show structures positive to iNOS. These findings imply t hat iNOS-generated NO could be involved in the pathophysiology of cochlear dysfunction in Meniere's disease. (C) 2000 Elsevier Science B.V. All rights reserved.