Effects of metaphit on phencyclidine and serotonin₂ receptors

We have investigated whether metaphit, a derivative of phencyclidine (PCP) which irreversibly binds to a population of PCP receptor sites in rat brain, blocks PCP-induced head-twitch response which is produced through serotonin₂ (5-HT₂) receptors, and also whether metaphit decreases the capacity of 5-HT₂ receptors. Metaphit ( 1 μmol rat) had decreased the intensity of PCP-induced head-twitch response and had depleted both PCP and 5-HT₂ receptors by 24 h after administration, but it failed to block 5-HT agonist 5-methoxy-N,N-dimethyltryptamine-induced 5-HT_1A receptor-dependent behaviors. These results reconfirmed our hypothesis that PCP and 5-HT₂ receptors may have very similar binding sites.