Enkephalin-like immunoreactivity in cochlear efferents in the bat, Rhinolophus ferrumequinum [corrected]

The cochlear efferent of the bat is anatomically different from other mammals. The olivocochlear bundle of the greater horse shoe bat, Rhinolophus ferrumequinum, projects only to inner hair cells. To examine the neurochemical nature of the olivocochlear bundle, we examined methionine-enkephalin-like immunoreactivity in this species. We observed immunoreactivity in the inner spiral bundles and in nerve fibers in the osseous spiral lamina. Sometimes immunostained inner spiral bundles were found to project towards inner hair cells. These data, as well as data from previous studies, suggest that cochlear efferents of different species of mammals share some common neurochemical features [corrected].