Orally active, subtype-selective NR1A/NR2B NMDA receptor antagonist (IC50 values are 5.3, 35000 and > 100000 nM for NR1A/2B, NR1A/2A and NR1A/2C receptor subtypes respectively). Potentiates the effect of L-DOPA in 6-OHDA-lesioned rats following oral administration.