Potent and selective NMDA antagonist that acts through the glycine site (IC50 = 5 nM). Displays > 500-fold selectivity over kainate and AMPA receptors (IC50 values are 2.7 and 3 μM respectively). Anticonvulsant in vivo following systemic administration. Also available as part of the NMDA Receptor - Glycine Site Tocriset™.