OBJECTIVES: 1) Guinea pigs have been treated with daily doses of 5mg/kg of ethacrynic acid for 10 days. Seven days later they were sacrificed and their cochlear potentials monitored. Electron microscopic analysis is being made of the organ of Corti and stria vascularis from one ear and hair cells counted in surface preparations from the opposite ear from each animal. 2) The relationship of the surface coat in the stria vascularis to the EP will be studied. Effects of neuraminidase on the EP and surface coat will be examined in guinea pigs.