The low energy conformation of MK801. (+)-N-allyl-N-normetazocine, dexoxadrol, etoxadrol and ketamine was found to possess the unique pharmacophore geometry of a PCP pharmacophore hypothesis recently reported by Carroll et al. (1988). Moreover, the union of the volumes of these compounds in their proposed receptor bound conformation locked together such that equivalent groups were superimposed showed that none of the compounds extended into the binding site volume above and below the aromatic ring and along the nitrogen vector.