CHARACTERIZATION OF [H-3]MEN-11420, A NOVEL GLYCOSYLATED PEPTIDE ANTAGONIST RADIOLIGAND OF THE TACHYKININ NK2 RECEPTOR

[H-3]MEN 11420, a radiolabeled glycosylated peptide antagonist of the tachykinin NK2 receptor, has been investigated in ligand-receptor bind ing assays using membranes of CHO cells transfected with the human tac hykinin NK2 receptor. [H-3]MEN 11420 bound to a single class of high a ffinity binding sites: its binding was inhibited by natural tachykinin s (potency ranking: NKA much greater than SP greater than or equal to NKB), as well as by peptide (MEN 11420 > MEN 10376 much greater than R 396) and nonpeptide (SR 48968 > GR 159897) selective NK2 receptor ant agonists. These data indicate that [3H]MEN 11420 is a potent radioliga nd for the human tachykinin NK2 receptor that may represent a useful t ool for studying ligand receptor interactions at the molecular level. (C) 1998 Academic Press.