Substance P and 21 related peptides containing isosteric or isofunctional groups were prepared by the solid-phase method. After purification by gel filtration and ion-exchange chromatography, the compounds were characterized by thin-layer chromatography, paper electrophoresis, and amino acid and elemental analysis. The biological activities of the peptides were evaluated in vitro on the guinea pig ileum, the rabbit mesenteric vein, and ...
