INVOLVEMENT OF THE N-METHYL-D-ASPARTATE RECEPTORS OF THE VESTIBULAR NUCLEUS IN THE GAZE-HOLDING SYSTEM OF THE CAT

Eye movements were recorded in alert cats after injections into one of the medial vestibular nuclei (MVN) either of a N-methyl-D-aspartate ( NMDA) antagonist or of a non-NMDA antagonist. A gaze-holding failure w as caused by the NMDA antagonist when it was injected into the central part of the MVN but not when it was injected into the rostral part of that nucleus. By contrast, injections of the non-NMDA-receptor antago nist into the MVN did not cause any sign of gaze-holding failure. We c onclude that the NMDA receptors located in the central part of the MVN are involved in the gaze-holding system.