Actions of bradykinin and related peptides on rabbit coeliac artery rings.
1. Rabbit coeliac artery rings were mounted in tissue baths containing Krebs solution at 37 degrees C in order to determine whether their response to bradykinin is initiated by B1- or B2-receptors. Tension was recorded isometrically. 2. Phenylephrine contracted the tissue. Subsequent addition of bradykinin or des Arg10-kallidin caused relaxation which was not dependent on an intact endothelium. Des Arg10-kallidin, a B1-receptor selective agonist, was more potent than bradykinin. 3. [beta-Thienyl alanyl6,9, D-Phe8]-kallidin and [Leu9]-des Arg10-kallidin antagonized bradykinin and des Arg10-kallidin. [Leu9]-des Arg10-kallidin, a B1-receptor selective antagonist, was more potent than [Thi6,9, D-Phe8]-kallidin, a less selective drug that acts on both B1- and B2-receptors. 4. Kinin-induced relaxation was reversibly antagonized by ibuprofen (a cyclo-oxygenase inhibitor) and by 5-(N,N-hexamethylene)amiloride (an inhibitor of Na+/H+ exchange). Ibuprofen caused a parallel shift to the right of a semi-logarithmic plot of the agonist concentration-effect relationship, whereas the amiloride analogue depressed the maximum response and reduced the slope. 5. We conclude that bradykinin and des Arg10-kallidin relax rabbit coeliac artery by combining with B1-receptors. The response is mediated by a cyclo-oxygenase product and may be influenced by cellular Na+/H+ exchange.
Ritter
J M
JM
Department of Clinical Pharmacology, Royal Postgraduate Medical School, London.
Doktor
H S
HS
Cragoe
E J
EJ
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002445:Celiac Artery / Q000187:drug effects*; D007052:Ibuprofen / Q000494:pharmacology; D066298:In Vitro Techniques; D016210:Methacholine Chloride; D008688:Methacholine Compounds / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D010455:Peptides / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D011817:Rabbits
D008688:Methacholine Compounds; D010455:Peptides; D016210:Methacholine Chloride; D010656:Phenylephrine; D001920:Bradykinin; D007052:Ibuprofen