Reversible blockade of vestibular evoked activity in the chick.

Vestibular evoked potentials (VsEP) were recorded from young chickens following bilateral intralabyrinthine injections of Tetrodotoxin (TTX). The purpose of this study was to document the long term effects of TTX on the electrophysiological activity of the vestibular system. VsEP components were eliminated within 30 min of TTX injections. Twelve hours post-treatment the early waves of the response began to emerge from the background noise. Recordings completed 24 h after the manipulation were not different from baseline responses. Our results indicate that TTX is a useful substance for reversibly blocking vestibular afferent pathways without permanently damaging the labyrinth or neural components. In addition, VsEP is an appropriate tool to objectively evaluate vestibular system function. Their combination can be applied to study the significance of afferent influences on the development and function of vestibular nuclei.