Ototoxicity and the olivocochlear bundle



Cochlear hair cell damage due to kanamycin sulfate was studied in chinchillas receiving 200 mg/kg kanamycin for nine days. The drug was given to a group of animals with lesions of the crossed olivocochlear bundle, a group that had received a sham operative procedure, and a group of normal animals. The animals were sacrificed 14 days after the last drug injection and the cochleae removed for examination by surface preparation. The lesioned animals showed markedly less hair cell loss than the control groups, and this was attributed to the fact that the loss of the efferent endings rendered these animals less susceptible to the ototoxic effects of kanamycin.