Abstract
We investigated species difference in cochlear dysfunction associated with experimental perilymphatic fistula using guinea pigs and chinchillas. The tone-burst elicited compound action potential (CAP) was studied in order to compare cochlear damages caused by an identical experimental method for perilymphatic fistula between the two species. A significant elevation of CAP threshold following laceration of the round window membrane was restricted to the highest frequency (12 kHz) in both species. Subsequent perilymphaspiration caused further CAP threshold elevation throughout all tested frequencies (2, 4, 8 and 12kHz) in both species. However, chinchillas showed greater threshold changes than guinea pigs. Histological examination revealed a rapture of the Reissner's membrane in two chinchillas with substantial CAP threshold changes following perilymph aspiration. These results indicate that cochlear of guinea pigs are less susceptible to experimental perilymphatic fistula than those of chinchillas.
