Captopril increases the affinity of bradykinin receptor binding sites in bovine coronary arterial endothelial cells.
In a radioligand binding study using bovine coronary artery endothelial cell membranes, captopril changed a single bradykinin (BK) binding site (Kd = 1.77 nM, Bmax = 60.2 fmol/mg protein) to high- (Kd = 0.68 pM, Bmax = 17.7 fmol/mg protein) and low- (Kd = 1.00 nM, Bmax = 72.5 fmol/mg protein) affinity binding sites. This effect was reversed by GppNHp. Captopril also enhanced BK-induced endothelium-dependent relaxation in saponin-treated coronary rings, and GppNHp partially suppressed this enhancement. These results suggest that captopril may affect BK receptors that couple to G-proteins.
Miyamoto
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A
Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University, Japan.
Matsuyama
T
T
Ishiguro
S
S
Nishio
A
A
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D002417:Cattle; D003331:Coronary Vessels; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D019204:GTP-Binding Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D018002:Receptors, Bradykinin / Q000378:metabolism*; D014664:Vasodilation / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D018002:Receptors, Bradykinin; D002216:Captopril; D019204:GTP-Binding Proteins