Kinins act on B1 or B2 receptors to release conjointly endothelium-derived relaxing factor and prostacyclin from bovine aortic endothelial cells.

1. Bradykinin (Bk) induced the coupled release of endothelium-derived relaxing factor (EDRF) and prostacyclin (PGI2) from bovine aortic endothelial cells grown in culture. The B2 kinin receptor antagonist, [D-Arg0,Hyp3,Thi5,8,D-Phe7]-Bk, abolished this release by Bk. 2. Des-Arg9-Bk, a B1 kinin receptor agonist, also induced the release of EDRF and PGI2, but much higher concentrations were required to obtain a similar release to that induced by Bk. 3. [Leu8],des-Arg9-Bk, a B1 receptor antagonist, significantly reduced the response to des-Arg9-Bk without affecting the release induced by Bk. 4. The release of EDRF and PGI2 induced by arachidonic acid or ADP was not significantly affected by the B2 or the B1 antagonist. 5. We conclude, therefore, that Bk and des-Arg9-Bk were acting respectively on B2 and B1 bradykinin receptors. 6. The possible role of kinin receptors in the release of EDRF and PGI2 from endothelial cells is discussed.