In vivo and in vitro actions of mammalian tachykinins.
Recently, two kassinin-like tachykinins have been isolated from mammalian nervous tissue. The potencies of these peptides, substance K (neurokinin alpha) and neuromedin K (neurokinin beta) were compared with those of substance P, eledoisin, and kassinin in various pharmacological systems in vivo and in vitro. In contracting the isolated guinea-pig ileum and rabbit jejunum the potencies of eledoisin, kassinin, substance K, and neuromedin K were 13-80% that of substance P. In the rat vas deferens substance K and neuromedin K potentiated the electrically induced contractions with potencies similar to those of eledoisin and kassinin; they were 46-236 times as potent as substance P. In stimulating salivation in the rat after intravenous injection, eledoisin, kassinin, and substance K were respectively 2.3, 1.3 and 0.33 times as potent as substance P. In contrast, neuromedin K exhibited negligible activity. Each peptide tested led to a short fall in blood pressure after intravenous injection in the rabbit, substance P being 12-250 times as potent as the other peptides. Substance P was 20 times as potent as substance K or neuromedin K in inducing vasodilatation in the rat hind paw in vivo. Of the peptides tested, only substance P (10 nmol/min) significantly increased the release of histamine from the rat isolated hindquarter preparation. The results are discussed with respect to several theories of tachykinin receptor heterogeneity.
U
U
Holzer-Petsche
E
E
Schimek
R
R
Amann
F
F
Lembeck
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004600:Eledoisin / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D006614:Hindlimb; D006636:Histamine Release / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D007583:Jejunum / Q000187:drug effects; D015286:Kassinin; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009419:Nerve Tissue Proteins / Q000494:pharmacology / Q000502:physiology*; D015288:Neurokinin A; D015287:Neurokinin B; D009842:Oligopeptides / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D012472:Salivation / Q000187:drug effects; D013373:Substance P / Q000494:pharmacology; D015320:Tachykinins; D014649:Vas Deferens / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D009419:Nerve Tissue Proteins; D009842:Oligopeptides; D015320:Tachykinins; D013373:Substance P; D015286:Kassinin; D004600:Eledoisin; D015288:Neurokinin A; D015287:Neurokinin B