CYTOLOGIC STRUCTURES UNIQUE TO DEITERS CELLS OF THE COCHLEA

Deiters cells in the gerbil cochlea disclosed unusual ultrastructural features. A sharp transition zone separated the cell body underlying o uter hair cells into an upper compartment with numerous organelles and a lower part devoid of structures other than the microtubule stalk. D eiters cells exhibited a unique structure, the rosette complex, which consisted of a core of densely fibrillar trabeculae, enclosed in a fil amentous meshwork and surrounded by tubulocisternal endoplasmic reticu lum. The dense trabeculae radiated in columns downward from an apical translucent area toward a lucent zone around the nucleus. They also sp read to the medial plasmalemma enveloping nerves and upward into the b ase of the phalanx. Frequent, small Golgi complexes bordered the tubul ar reticulum. The distinctive mitochondria of Deiters cells frequently paralleled the plasmalemma, revealed an elongated, often arched profi le, and contained sparse, longitudinally aligned cristae. The stalk, c omposed of characteristic microtubule bundles resembling those in pill ar cells, ascended from basal to apical plasmalemma of the cell body a nd into the phalanx and reticular lamina as previously described. The stalk appeared also to ramify into smaller microtubule bundles in apic al cytosol penetrating the rosette complex. Nuclei in Deiters cells di ffered from those in hair cells in their location high in the cell and in showing chromatin dispersion indicative of more active protein syn thesis. (C) 1993 Wiley-Liss, Inc.