title: Pharmacological characterization of a substance P antagonist, [D-Arg1,D-Pro2,D-Trp7,9,Leu11]-substance P.
abstract: The substance P antagonist [D-Arg1,D-Pro2,D-Trp7,9,Leu11]-substance P produced parallel log dose-response curve shifts to both substance P and eledoisin on five in vitro smooth muscle preparations. The slope values of Arunlakshana-Schild plots were not significantly different from unity suggesting that it acts as a simple competitive antagonist on all five preparations with an association constant (Ka) in the range of 0.3-1.5 X 10(6)M-1. The Ka value of the antagonist was always slightly greater when tested against eledoisin than against substance P; however, this difference appears too small to suggest that these two agonists are acting on different receptor sub-types.
mesh_terms: D000818:Animals; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004600:Eledoisin / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008647:Mesocricetus; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013373:Substance P / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: D013373:Substance P; D004600:Eledoisin; C038073:substance P, Arg(1)-Pro(2)-Trp(7),(9)-LeuNH(2)(11)-