title: Structure-activity studies of heptapeptide derivatives related to substance P, neurokinin A, B and other tachykinins on smooth muscles.
abstract: Diverse C-terminal heptapeptide derivatives related to substance P, kassinin, physalaemin, neurokinin A and B were synthesized and the contracting activities on the guinea pig ileum as well as rat duodenum were compared. In the partial sequence of C-terminal of tachykinin peptides, -I-II-Phe-III-Gly-Leu-Met-NH2, the combination of amino acid residues at positions I and III have significant roles in contraction of smooth muscle. For the activation of rat duodenal muscle (SP-E), Asp(I) and aliphatic amino acid(III), and for guinea pig ileal muscle(SP-P), Gln(I) and aromatic amino acid(III) are essential. Moreover, guinea pig ileum is sensitive to a full sequence of neurokinin peptides.
mesh_terms: D000818:Animals; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D015288:Neurokinin A; D015287:Neurokinin B; D009479:Neuropeptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D017981:Receptors, Neurotransmitter / Q000145:classification / Q000187:drug effects; D018039:Receptors, Tachykinin; D013329:Structure-Activity Relationship; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D009479:Neuropeptides; D017981:Receptors, Neurotransmitter; D018039:Receptors, Tachykinin; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B