Morphological polarizations of sensory hair cells in the three otolithic organs of a teleost fish: fluorescent imaging of ciliary bundles.

It has been suggested that the morphological polarity of sensory hair cells in the otolithic organs plays important roles in directional hearing in fish. In this study, we examined the hair cell polarization patterns in the saccule, utricle, and lagena of a teleost fish, the sleeper goby (Dormitator latifrons). In contrast to using traditional scanning electron microscopy, we employed a simple and rapid method that enabled us to map the hair cell polarization patterns using immunocytochemical and confocal imaging techniques. The hair cells in the caudal part of the saccular epithelium are oriented dorsally and ventrally, with some variations in the caudal end. The hair cells in the rostral part have diverse morphological polarizations. The utricular hair cells fall into internal and external groups which have opposing polarizations. The lagenar hair cells are found in anterior and posterior groups with approximately opposite polarizations. The saccular and lagenar epithelia are oriented perpendicular to the horizontal plane of the fish, while the utricular epithelium lies on the horizontal plane. Thus, the sleeper goby's ear is morphologically capable of being a three-dimensional sound detector.