RECENT ADVANCES IN THE PHARMACOLOGY OF THE VESTIBULOOCULAR REFLEX SYSTEM

Recent advances in the pharmacology of the vestibule-ocular reflex hav e had a major impact on our understanding of the vestibular system, th e sensory system primarily concerned with the stabilization of gaze an d posture during head movement. Increasing evidence suggests that affe rent transmission from the receptor hair cells in the vestibular labyr inth to the vestibular nerve probably involves glutamate acting on a n umber of excitatory amino acid receptor subtypes. Furthermore, hair-ce ll sensitivity appears to be regulated by cholinergic, GABA-mediated a nd, possibly, peptide-mediated efferent feedback from the CNS. Likewis e, it seems clear that an excitatory amino acid, probably glutamate, i s the major transmitter used by the Vestibular nerve in its synapses w ith neurones of the brainstem vestibular nucleus. In this review, Paul Smith and Cynthia Darlington discuss the targe number of receptor sub types that have been identified in the vestibular nucleus, including r eceptors for several peptides that may have a rote in co-transmission.