AUDIOLOGICAL STUDY IN GUINEA-PIGS WITH TYPE-I ALLERGY INDUCED IN THE INNER-EAR

Time course studies of electrocochleography and the auditory brain ste m response were performed in guinea pigs that were passively sensitize d by sera containing antidinitrophenyl reaginic antibody and specifica lly challenged by dinitrophenyl-bovine serum albumin injected through the stylomastoid foramen. A negative summating potential on electrococ hleography was observed from 12 to 48 hours, but not at 72 hours, afte r the specific challenge. A threshold increase on the auditory brain s tem response was observed 15 minutes after the specific challenge; the threshold recovered to the prechallenge level within 7 days. Further, we used Tranilast, a blocking agent of chemical mediator release from mast cells, before the specific challenge. A negative summating poten tial and head deviation were not observed after the use of this agent. These results suggest that the auditory change provoked in the inner ear of the sensitized guinea pig may have been induced by type I aller gy.