High-affinity bradykinin B2 binding sites sensitive to guanine nucleotides in bovine aortic endothelial cells.
Bradykinin (BK) binding sites were studied in membranes from bovine aorta. [3H]BK specifically bound to one high-affinity binding site (KD = 152 pM; Bmax = 4.6 fmol.mg-1) and was displaced by unlabeled BK (Ki = 121 pM). The B2-agonist kallidin and B2-antagonists D-Arg0[Hyp3,Leu5,8,Gly6,D-Phe7]BK, D-Arg0[Hyp3,D-Phe7]BK, [D-Phe7]BK, and [Thi5,8,D-Phe7]BK inhibited [3H]BK binding with respective Ki values of 101, 282, 678, 2000 and 6000 pM. The B1-antagonist des-Arg9[Leu8]BK had no effect. GTP, GTP gamma S, GDP, and GDP beta S but not 5'-GMP, guanosine, cyclic 3',5'-GMP, ATP, ADP, 5'-AMP, nor adenosine, inhibited [3H]BK binding with an IC50 of 1-3 microM for GTP and GDP and an IC50 of 0.1-0.3 microM for GTP gamma S and GDP beta S. GTP and GDP at 3 microM decreased the Bmax value by 30-70%. Millimolar concentrations of Ca2+ and Mg2+ ions increased [3H]BK binding and counteracted the effect of guanine nucleotides. This study demonstrates the existence of a specific high-affinity B2 BK binding site in bovine aortic endothelial cells. It suggests that this site is located on a G protein-interacting receptor.
Keravis
T M
TM
Laboratoire de Pharmacologie Cellulaire et Moléculaire, CNRS URA 0600, Université Louis Pasteur de Strasbourg, Illkirch, France.
Nehlig
H
H
Delacroix
M F
MF
Regoli
D
D
Hiley
C R
CR
Stoclet
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta; D001665:Binding Sites; D001920:Bradykinin / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000037:antagonists & inhibitors / Q000378:metabolism
D006150:Guanine Nucleotides; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; D001920:Bradykinin