Regional heterogeneity of rat brain phencyclidine (PCP) receptors revealed by photoaffinity labeling with [³H] azido phencyclidine

Photoaffinity labeling of rat brain phencyclidine (PCP) receptors with [³H] azido phencyclidine ([³H]AZ-PCP) reveals the existence of five polypeptides which are specifically labeled by the affinity probe (Mr's 90,00, 62,000, 49,000, 40,000 and 33,000). These labeled components are unevenly distrbuted in rat brain. In the frontal cortex, thalamus and olfactory bulb, the major bands labeled are the Mr's 90 K and 62 K polypeptides; in the cerebellum most of the labeling is in the 90 K and 33 K bands; and in the hippocampus all but the Mr 40 K band are heavily labeled. Together with dexoxadrol/[³H]PCP competition binding data, which indicated the existence of high and low affinity dexoxadrol/PCP binding sites, these results suggest regional heterogeneity of PCP receptors. The regional distribution of the high affinity dexoxadrol binding sites correlates best with that of the Mr 90 K polypeptide.