The inner ear macular sensory epithelia of the Daubenton's bat

The inner ear macular sensory epithelia of the Daubenton's bat were examine d quantitatively to estimate the area and total number of hair cells. Ultra structural examination of the sensory epithelium reveals two main types of hair cells: the chalice-innervated hair cell and the bouton-innervated hair cell. The existence of an intermediate type, with a nerve ending covering the lateral side of the hair cell, indicates that the chalice-innervated ha ir cells are derived from bouton-innervated hair cells. Thus, at least a pa rt of the bouton-innervated hair cells forms a transitional stage. A number of immature as well as apoptotic hair cells were observed. It is suggested that a continuous production of new hair cells takes place in mature indiv iduals, probably based on transdifferentiation. of supporting cells. J. Com p. Neurol. 438:433-444, 2001. (C) 2001 Wiley-Liss, Inc.