High and low affinity psychotomimetic opioid binding sites: characterization by a novel 3H-PCP-analog.

1-[1-(3-Hydroxyphenyl)cyclohexyl]piperidine (PCP-3-OH) is one of the most potent analogs of phencyclidine (PCP). In the present study we describe the binding properties of 3H-PCP-3-OH to guinea pig brain membranes. Scatchard analysis of saturation binding studies revealed the existence of high (0.44nM) and low (17nM) affinity binding components. High affinity binding sites were completely blocked in the presence of (+)SKF 10047 (50nM). In competition studies PCP analogs compete for 3H-PCP-3-OH specific binding in a monophasic manner whereas psychotomimetic opioid ligands compete for this binding in a biphasic manner. Results from both saturation and competition experiments suggest the existence of a common high affinity binding site for psychotomimetic opioid ligands and PCP analogs and a low affinity binding component primarily for phencyclidines.