Expression of alpha-actinin in the stereocilia of hair cells of the inner ear: immunohistochemical localization.

The distribution of alpha-actinin was studied on surface preparations and cryosections from the organ of Corti of the adult rat by using polyclonal and monoclonal antibodies to smooth muscle alpha-actinin. The polyclonal antibody used gave a positive immunoreactivity in the cuticular plate of the hair cells, pillar cells and supporting cells. A specific labelling of the stereocilia of the outer hair cells (OHCs) and inner hair cells (IHCs) on surface preparations was highly visible. The monoclonal antibody used produces similar patterns of labelling in the organ of Corti. The possible roles of this protein in hair cells are discussed.