Ultrastructure of the Vestibular Sensory Areas in Experimental Lathyrism

Abstract

The effects of β-aminopropionitrile (BAPN), a lathyrogenic substance, on the vestibular sensory areas of the rat were studied by means of electron microscopy. Degenerative changes occurred in both the type I and type II hair cells, with swelling of mitochondria, numerous large laminated inclusions, vacuolization and protrusion of the supranuclear cytoplasm. The nerve endings showed only mild degeneration. In the connective layer, numerous large membranous whorls were seen enclosing lipid droplets and smooth vesicles. It is suggested that these lesions are primarily due to a disturbance in protein metabolism. The study is a further example of ototoxicity and indicates that lesions in the vestibular end organs play a role in the pathogenesis of experimental lathyrism.