Vestibular compensation modifies the sensitivity of vestibular neurones toinhibitory amino acids

The progressive disappearance of the postural and oculomotor syndrome trigg ered by unilateral labyrinthectomy (vestibular compensation) is a model of plasticity in the adult central nervous system. This recovery may involve m odifications of the pharmacological profile of central vestibular neurones, in particular their sensitivity to inhibitory amino acids. We therefore co mpared the sensitivity of medial vestibular nucleus neurones to glycine and muscimol in slices taken either from control animals, or from guinea-pigs labyrinthectomized 3 days before. We demonstrate that the loss of excitator y inputs experienced by the ipsilesional vestibular neurones induces a decr ease in their sensitivity to inhibitory amino acids. These pharmacological changes should facilitate the recovery of a normal balance between the aver age resting discharge of neurones in both vestibular nuclei. NeuroReport 11 :1921-1927 (C) 2000 Lippincott Williams & Wilkins.