Endolymphatic hydrops was surgically induced in the left ears of albino guinea pigs. In the 6th, 12th, and 24th postoperative weeks, cochlear endolymphatic potential (CEP) was measured through the round window. The averages of CEP in each postoperative period after one month were found to be lower than normal controls by 20mV or more. Maximal values of CEP reduction after Furosemide injection (50mg/kgBW) in hydropic ears were greater than those in normal controls. After maximal reduction CEP rapidly recovered to the original level in normal controls and hydropic ears in the 6th postoperative week. Recovery rate was slower in the 12th week animals, and CEP never reached the original level in the 24th. Consequently, CEP susceptibility to Furosemide is considered to correspond to the morphological changes of stria vascularis in hydropic ears.
