[H-3] MK-801 BINDING TO WELL-WASHED RAT-BRAIN MEMBRANES FOLLOWING CESSATION OF CHRONIC PHENCYCLIDINE TREATMENT

Rats were implanted with osmotic minipumps SC that infused either sali ne or 10 mg/kg/day phencyclidine (PCP) for 10 days, a regimen that pro duces dependence to PCP. At the end of this 10-day infusion period, th e pumps were removed and the rats were sacrificed either immediately o r at various time points (12 h, 1, 2, and 7 days) after pump removal. The saturation binding parameters of [H-3]MK-801 were then determined in well-washed cortical/hippocampal membranes prepared from these rats . Neither the B-max nor the K-d of [H-3]MK-801 binding in membranes of PCP-treated rats differed from that determined using membranes from s aline-treated rats at any time point studied. These results suggest th at alterations in PCP receptors do not play a major role in the produc tion of PCP dependence.