Synthesis, in vitro binding profile, and autoradiographic analysis of [3H]-cis-3-[(2-methoxybenzyl)amino]-2-phenylpiperidine, a highly potent and selective nonpeptide substance P receptor antagonist radioligand.

The synthesis of a highly potent and selective NK1 receptor antagonist radioligand, [3H]-cis-3-[(2-methoxybenzyl)amino]-2-phenylpiperidine (6a) is described. The in vitro binding pharmacology and autoradiographic distribution of 6a in guinea pig brain following peripheral administration are also reported.

Synthesis, in vitro binding profile, and central nervous system penetrability of the highly potent 5-HT3 receptor antagonist [3H]-4-(2-methoxyphenyl)-2-[4(5)-methyl-5(4)-imidazolylmethyl]thiazole.

4-(2-Methoxyphenyl)-2-[4(5)-methyl-5(4)-imidazolylmethyl]thiazole (5) is a highly potent member of a structurally novel series of selective serotonin-3 receptor antagonists. The synthesis of tritiated 5 and its binding profile in neuroblastoma-glioma 108-15 cells are described. Furthermore, in vivo studies in rat with this radioligand indicate that it effectively penetrates the blood-brain barrier upon peripheral administration. Thus, 5 should be a useful pharmacological tool for both in vitro and in vivo studies of this class of compounds.