The time-course of furosemide-induced strial changes in guinea pigs after pretreatment with daltroban.

It was shown previously (Ernst et al., 1989) that pretreatment of guinea pigs with a thromboxane (TX) receptor antagonist attenuates the decline of the endocochlear potential (EP) induced by furosemide. The present paper is aimed at investigating a possible correlation between the electrophysiological data and ultrastructural changes of the stria vascularis by electron microscopy. The dosages of 40, 60, and 80 mg/kg furosemide were injected after the pretreatment with the TX receptor antagonist daltroban and compared to controls which were injected with furosemide only. It was found at all furosemide concentrations that the strial changes 10 min after injection were nearly unchanged against controls. 30 min after furosemide injection, the most pronounced changes were seen when pretreating the animals: a clear reduction of the marginal cell swelling and edema in general were observed at 40 and 60 mg/kg furosemide. The guinea pigs injected with 80 mg/kg furosemide after pretreatment displayed nearly the same changes as controls.