The importance of C-terminal residues of vertebrate and invertebrate tachykinins for their contractile activities in gut tissues.
The C-terminal residues of mammalian tachykinins and urechistachykinins (Uru-TKs), tachykinin-related peptides of echiuroid worm origin, were substituted for each other. Their contractile effects were assayed on the cockroach hindgut and the guinea pig ileum. [Met(10)] substitution of Uru-TKs caused a 1000 times lower activity on the hindgut, but a 1000 times higher activity on the ileum. In contrast, [Arg(11)]substance P (SP) was 100 times more and 400 times less potent than SP on the hindgut and ileum, respectively. A SP antagonist blocked these Uru-TK activities on the hindgut. These results demonstrated that the C-terminal Met-NH(2) is necessary for ileum contraction and the Arg-NH(2) is required for hindgut contraction, which was caused by binding to the cockroach's neurokinin-like receptor.
Ikeda
T
T
Suntory Institute for Bioorganic Research, Shimamotocho, Osaka, Japan.
Minakata
H
H
Nomoto
K
K
D019943:Amino Acid Substitution; D000818:Animals; D001120:Arginine / Q000737:chemistry; D003058:Cockroaches; D006168:Guinea Pigs; D015801:Helminth Proteins / Q000737:chemistry / Q000494:pharmacology; D008297:Male; D008715:Methionine / Q000737:chemistry; D009119:Muscle Contraction / Q000187:drug effects*; D015288:Neurokinin A / Q000737:chemistry* / Q000494:pharmacology; D015287:Neurokinin B / Q000737:chemistry* / Q000494:pharmacology; D009479:Neuropeptides / Q000737:chemistry* / Q000494:pharmacology; D013045:Species Specificity; D013373:Substance P / Q000494:pharmacology
D015801:Helminth Proteins; D009479:Neuropeptides; C080807:urechistachykinin I; C080808:urechistachykinin II; D013373:Substance P; D015288:Neurokinin A; D015287:Neurokinin B; D001120:Arginine; D008715:Methionine