Differential effect of the loop diuretic furosemide on short latency auditory and vestibular-evoked potentials

Objective: This study aimed to investigate the differential effect of the loop diuretic furosemide on the auditory and vestibular (otolith) end organs in the same animals simultaneously. Design and Methods: Auditory nerve-brain stem-evoked responses (ABR-generated in the cochlea) and short latency vestibular-evoked responses to linear acceleration impulses (L-VsEP- generated in the otolith organs) were recorded from albino Sabra rats both before and at minute intervals after intravenous injections of the loop diuretic furosemide. In some animals, an equal volume of saline was injected to control for the effect of the injection itself. In most animals, more than one injection of saline or furosemide was possible (furosemide, N = 17 injections in 10 rats; saline, N = 18 injections in 9 rats). Peak-to-peak amplitude and peak latency changes in the first wave in each recording (representing end-organ activity) as a function of postinjection time were compared between the two evoked potentials using analysis of variance and repeated t-tests. Results: Saline injections caused only minor changes in the amplitude of the ABR and the L-VsEP. After administration of furosemide, the amplitude of the L-VsEP hardly changed. However, there was a noticeable decrease in the amplitude of the ABR. Conclusions: Although furosemide has a major depressant effect on cochlear function, vestibular end-organ activity is hardly altered.