Facilitation of responses to AMPA but not kainate by cyclothiazide in primate somatosensory thalamus

This study examines the possibility of multiple ionotropic non-N- methyl-d-aspartate (NMDA) receptors in the chief sensory nuclei of the primate thalamus. Cyclothiazide, an antagonist of rapid desensitization of non-NMDA receptors, is shown to produce a facilitation of responses to the synthetic agonist (±)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) but not kainate or NMDA in cells of the ventral posterior lateral and medial thalamic nuclei in the anesthetized monkey. These differential effects suggest the presence of multiple ionotropic non-NMDA excitatory amino acid receptors in the primate ventral posterior (VP) thalamus. Cyclothiazide- sensitive excitatory amino acid receptors have important roles in mechanisms of plasticity and excitotoxicity in other neural systems and so may mediate similar mechanisms in the somatosensory thalamus.