An NMDA receptor antagonist; blocks NMDA-induced currents in rat retinal ganglion cells by 90% at 12 μM; reverses I1PP2A-induced inhibition of dephosphorylation of tau194-207 in vitro; restores PP2A activity, decreases GSK-3β and Aβ levels in the hippocampus, cerebral cortex, and ventricular areas, and attenuates spatial learning and memory in the AAV1-I1PP2A rat model of Alzheimer's disease at 2 mg/kg; reduces responding on the ethanol-associated lever in a cue-induced ethanol seeking test in rats at 20 mg/kg; decreases secretion of MMP-9, degradation of collagen IV, the size of cerebral ischemia-induced brain infarcts, and neuronal cell death in a mouse model of focal cerebral ischemia,