Bradykinin receptors in the guinea-pig taenia caeci are similar to proposed BK3 receptors in the guinea-pig trachea, and are blocked by HOE 140.
1. Bradykinin (BK) receptors of the guinea-pig taenia caeci were compared with those of the guinea-pig trachea, a preparation proposed to possess novel BK3 receptors. 2. Bradykinin-evoked contractile responses were unaffected in both preparations by the selective BK1 receptor antagonist [des-Arg9,Leu8]-BK (1 microM-10 microM). The BK2 receptor antagonists, D-Arg-[Hyp3,D-Phe7]-BK and D-Arg-[Hyp3,Thi5,8,D-Phe7]-BK, both had low affinities (apparent pKB estimates less than 6) which did not differ significantly between the two preparations (P greater than 0.05). In contrast, the novel bradykinin receptor antagonist D-Arg-[Hyp3,Thi5,D-Tic7,Oic8]-BK (HOE 140) potently antagonized responses to bradykinin with relatively high affinity (apparent pKB = 8.42 +/- 0.15 and 8.94 +/- 0.16 in the taenia caeci, and trachea, respectively). 3. We conclude that the bradykinin receptors in the guinea-pig taenia caeci have similar recognition properties to those present in the guinea-pig trachea, and in this respect the taenia caeci represents a useful preparation for the further study of proposed novel BK3 receptors.
Field
J L
JL
Division of Biomedical Sciences, King's College London.
Hall
J M
JM
Morton
I K
IK
D000595:Amino Acid Sequence; D000818:Animals; D001920:Bradykinin / Q000378:metabolism* / Q000031:analogs & derivatives; D002432:Cecum / Q000187:drug effects / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology*; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014132:Trachea / Q000187:drug effects / Q000378:metabolism
D009842:Oligopeptides; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; C065679:icatibant; D001920:Bradykinin