Antinociceptive action of GLYX-13: an N-methyl-D-aspartate receptor glycine site partial agonist.

Inhibition of N-methyl-D-aspartate (NMDA)-mediated neurotransmission has been demonstrated to provide antinociceptive actions in a number of animal models of tonic and neuropathic pain. However, both competitive and noncompetitive NMDA receptor antagonists are ataxic at analgesic doses. Partial agonists and antagonists of the NMDA-associated glycine site have demonstrated antinociceptive actions at doses that are not ataxic. In this study, we present data showing that GLYX-13, an NMDA receptor, glycine-site, partial agonist, also is antinociceptive in the rat formalin model of tonic pain and in the rat constriction nerve injury model of neuropathic pain at doses not inducing ataxia.