Effect of loop-diuretics on hair cells of the cochlea in guinea pigs. Histological and histochemical study.

The present study revealed the following early changes in pinna reflex and in inner ear morphology of guinea pigs treated intravenously with furosemide (100 mg/kg) or ethacrynic acid (80 mg/kg). (A) Transient loss of pinna reflex occurred in wide frequency range (20K-500 Hz) immediately after the treatment. (B) Narrowing of deeper capillary network of the stria vascularis occurred soon after the treatment. The change was reversible. (C) Outer hair cells underwent cytoplasmic swelling and marked depression of supravital reduction of Nitro-BT. These changes were reversible. (D) Relationship between these changes and functional alteration of the cochlea was discussed.