Autoradiographical Distribution of Locally Applied Dihydrostreptomycin in the Inner Ear

Abstract

H₃-labelled dihydrostreptomycin (DHS) in isosmolar solution is perfused through the cochlea of guinea pigs. After varying incubation periods the distribution of the radioactivity in the cochlear duct is shown by autoradiography. Because of the water solubility of DHS, freeze drying of the tissue is applied. Maximum radioactivity is clearly seen over the inner and outer hair cells and over the nerve tissue of ossetis spiral lamina. This seems to indicate that the specific sensitivity of the sensory cells to DHS is not only due to thz long persistence of the substance in the perilymph but also to a specific affinity of the drug to their cytoplasm. Presumably DHS is attached reversibly to the ribosomes of the hair cells as described in bacteria.