EFFECT OF GENTAMICIN ON THE MELANOSOMES IN THE STRIA VASCULARIS OF THE PIGMENTED GUINEA-PIG - AN ULTRASTRUCTURAL-STUDY

Melanosomes of the stria vascularis in gentamycin (GM)-intoxicated gui nea pigs were examined ultrastructurally. Experimental animals were gi ven GM sulfate intramuscularly in a daily adjusted dose of 100 mg/kg f or 15 consecutive days (group A), and 150 mg/kg for 5 consecutive days (group B). Melanosomes of the intermediate cells in group B significa ntly increased in number in comparison with those in group A and the c ontrol group. Melanosomes in the apical turn outnumbered those in the basal turn in all three groups. Cytochemically, Na+, K+-ATPase activit y was also demonstrated in the marginal cells. There was little differ ence in the degree of enzyme activity between groups A, B and the cont rol group. The role and significance of melanosomes of the stria vascu laris are discussed.