title: A radioiodinated linear vasopressin antagonist: a ligand with high affinity and specificity for V1a receptors.
abstract: A linear vasopressin antagonist, Phaa-D-Tyr(Me)-Phe-Gln-Asn-Arg-Pro-Arg-Tyr-NH2 (Linear AVP Antag) (Phaa = Phenylacetyl), was monoiodinated at the phenyl moiety of the tyrosylamide residue at position 9. This antagonist appeared to be a highly potent anti-vasopressor peptide with a pA2 value in vivo of 8.94. It was demonstrated to bind to rat liver membrane preparations with a very high affinity (Kd = 0.06 nM). The affinity for the rat uterus oxytocin receptor was lower (Ki = 2.1 nM), and affinities for the rat kidney- and adenohypophysis-vasopressin receptors were much lower (Ki = 47 nM and 92 nM, respectively), resulting in a highly specific vasopressin V1a receptor ligand. Autoradiographical studies using rat brain slices showed that this ligand is a good tool for studies on vasopressin receptor localization and characterization.
authors.affiliation: Centre CNRS-INSERM de Pharmacologie-Endocrinologie, Montpellier, France.
authors.forename: A
authors.initials: A
authors.lastname: Schmidt
authors.forename: S
authors.initials: S
authors.lastname: Audigier
authors.forename: C
authors.initials: C
authors.lastname: Barberis
authors.forename: S
authors.initials: S
authors.lastname: Jard
authors.forename: M
authors.initials: M
authors.lastname: Manning
authors.forename: A S
authors.initials: AS
authors.lastname: Kolodziejczyk
authors.forename: W H
authors.initials: WH
authors.lastname: Sawyer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D005260:Female; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008024:Ligands; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D017483:Receptors, Vasopressin; D014667:Vasopressins / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D007457:Iodine Radioisotopes; D008024:Ligands; D009842:Oligopeptides; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins; C068793:phenylacetyl-O-methyltyrosyl-phenylalanyl-glutaminyl-asparaginyl-prolyl-arginyl-tyrosinamide