[Ultrastructural localization of immune reactions to met-enkephalin antibodies in the organ of Corti].

Using a pre-embedding immunoperoxidase technique, enkephalin-like substances were described, at the ultrastructural level, in efferent terminals of the guinea pig cochlea. These fibers were located in the inner spiral bundle and the tunnel spiral bundle. No immunoreaction was detected under the outer hair cells. Most of the immunoreactive fibers contacted afferent dendrites; synaptic differentiations were seen, suggesting a possible inhibitory effect of the enkephalin immunoreactive efferents upon the auditory afferents.