PD 144418 oxalate is a remarkably potent and selective sigma1 receptor ligand having potential antipsychotic properties. PD 144418 oxalate displayed an apparent affinity (Ki) of 0.08 nM for sigma1 sites in guinea pig brain membranes and a Ki of 1377 nM for sigma2 sites in rodent neuronal NG108-15 cell membranes. PD 144418 oxalate was classified as sigma1 receptor antagonist based upon several assays, including the ability to attenuate mescaline-induced scratching in mice. PD 144418 oxalate attenuates cocaine-induced hyperactivity in mice. It showed potential antipsychotic activity, but no antidepressant or anxiolytic actions.

PEAQX (NVP-AAM 077) is a potent and orally active NMDA antagonist with a 15-fold preference for human NMDA receptors with the 1A/2A(IC50=270 nM), rather than 1A/2B (29,600 nM). Animals treated with PCP or PEAQX on PN7, PN9, and PN11 showed a sensitized locomotor response to PCP challenge on PN28-PN35. PEAQX induced social suppression in rats.