Jpn. J. Pharmacol. 84 (1), 82-85 (2000)

Captopril Increases the Affinity of Bradykinin Receptor Binding Sites in Bovine Coronary Arterial Endothelial Cells

Atsushi Miyamoto, Tomoko Matsuyama, Shigeru Ishiguro and Akira Nishio

Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan

Abstract: 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.

Keywords: Bradykinin, Captopril, Coronary artery

Copyrightę The Japanese Pharmacological Society 2000

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