Discriminative stimulus effects of monohydroxylated phencyclidine metabolites in Rhesus monkeys.

Rhesus monkeys were trained to discriminate saline from an injection of ketamine. In tests of stimulus generalization, phencyclidine (PCP) produced dose-related ketamine-appropriate responding in each monkey. Two monohydroxylated PCP metabolites also produced ketamine-like discriminative effects, although only at considerably higher doses than did PCP. A third monohydroxylated PCP metabolite produced only sham-appropriate responding. The results suggest that these PCP metabolites contribute little to the behavioral actions of PCP in the monkey.