Abstract
It has been reported that ethacrynic acid (ETA) reduced the ampullar endolymphatic potential (AEP) and inhibited the vestibular function. In the present study, in order to examine the effect of ETA upon the resting discharge of vestibular first order neuron, the single unit action potential was recorded from the superior vestibular nerve of the guinea pig and the effect of ETA upon the interspike interval was examined. Hundred to 150mg/kg administration of ETA inhibited the neural activity in the majority of the case. In 3 out of 7 case, ETA of 50mg/kg which had no effect upon AEP decreased the interspike interval or diminished the potential.
The results suggested that the inhibition of vestibular function by ETA is due to not only the reduction of EP but also the direct effect of sensory organ or nerve fibers.
