Electron Microscopic Study of Semicircular Canal Organs and Otolith Organs of Squirrel Monkeys after Administration of Streptomycin Sulfate

Abstract

Pathological findings in the ultrastructure of the semicircular canal and otolith organs of six squirrel monkeys after administration of streptomycin sulfate are described. The monkeys were sacrificed at predetermined points in the suppression of their vestibular function as shown by the caloric threshold value, and the cristae and maculae examined by electron microscopy. Initial ultrastructural pathology of vestibular apparatus was observed. At all points of vestibular suppression, the most striking feature was that no significant pathology of ultrastructure was seen in the hair cells of the saccular maculae, but was observed in the sensory epithelium of the utricular maculae and cristae. The ototoxic mechanism of streptomycin to the vestibular neuroepithelium was discussed from the morphophysiological point of view.