Discriminative stimulus properties of phencyclidine (PCP)-related compounds: correlations with 3H-PCP binding potency measured autoradiographically.

Several PCP analogs, the putative PCP agonist MDP, and the sigma receptor agonists SKF-10,047 and dexoxadrol were tested for their ability to substitute for PCP in animals trained to discriminate PCP from saline. The potencies of these compounds in substituting for PCP in the behavioral task correlated with their abilities to inhibit the specific binding of 3H-PCP to rat hippocampal sections measured autoradiographically, which occurred at a single class of sites with an affinity of 85 nM and a capacity of 2646 fmol/mg protein. In addition to this specific binding, an additional nonspecific but displaceable fraction of total 3H-PCP binding was present. These results suggest that the specific 3H-PCP binding site measured in the hippocampus may be the type of binding site which mediates the behavioral effects of PCP and related compounds. Therefore, measurement of the inhibition of 3H-PCP binding at this site might aid in the search for PCP antagonists.