Tachykinin Antagonist I: Specific, Competitive and Tissue-Selective Neurokinin B Antagonists on Contractile Activity in Smooth Muscles

Abstract

Two neurokinin B (NKB) analogs, [Gly⁶]-NKB [3-10] and [Arg³, DAla⁶]-NKB [3-10], were tested for agonistic activity as well as for their ability to antagonize the myotropic actions of NKB, neurokinin A, substance P, physalaemin and eledoisin in isolated guinea-pig ileum, guinea-pig urinary bladder, rat duodenum, rat vas deferens and rat portal vein. [Gly⁶]-NKB [3-10] in the guinea-pig ileum and rat portal vein and [Arg³, D-Ala⁶]-NKB [3-10] in the guinea-pig ileum were found to be the first specific and competitive antagonists against NKB.