The binding of a series of phenylpiperazines (3) and benzoylpiperazines (4) to central serotonin (5-HT) sites was investigated. Several derivatives of 3 displayed nanomolar affinities for 5-HT1 sites, whereas derivatives of 4 were essentially inactive both at 5-HT1 and 5-HTz sites. 1-(2-Methoxyphenyl) piperazine (2-MPP, 3a) was found to possess an affinity (Ki= 35 nM) for 5-HT1 sites comparable to that of the recognized 5-HT agonist 1-[3- ...
