Localization of an aminoglycoside (streptomycin) in the inner ear after its systemic administration

Summary We used the simple method of direct cytofluorescence to detect the presence of the aminoglycoside, streptomycin, in the inner ear after its systemic administration. In the cochlea, fluorescence was observed in the organ of Corti, the spiral ganglion, the nerve fibres, the vascular stria and Reissner's membrane; in the vestibulum, fluorescence was seen in the crista ampullaris and the planum semilunatum. The localization of the drug was related to the distribution of its specific receptor, triphosphoinositide (TPI); therefore, it is reasonable to assume that aminoglycosides exert their toxic effects by binding to TPI.Supported by grants of Ministero della Pubblica Istruzione, Italy