The difference in endocochlear and endolymphatic sac d.c. potentials in response to furosemide and canrenoate as diuretics.

We investigated the effects of furosemide, a loop diuretic, and canrenoate, an aldosterone antagonist, on the endocochlear potential (EP) and the endolymphatic sac potential (ESP) in the guinea pig. Furosemide produced no significant change in the ESP at a dose of 100 mg/kg after an intravenous infusion for 20 min. However, this dose decreased the EP to a negative level. Canrenoate produced no significant change in the EP at an intravenous dose of 300 mg/kg for 20 min, but it did decrease the ESP. The differences in the EP and ESP in the response to the diuretics indicate a dissimilarity of the origin of both d.c. potentials in the endolymphatic space.