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ETB receptor antagonist, IRL 1038, selectively inhibits the endothelin-induced endothelium-dependent vascular relaxation

1993; Elsevier BV; Volume: 231; Issue: 3 Linguagem: Inglês

10.1016/0014-2999(93)90112-u

1879-0712

Hideaki Karaki, Sri Agus Sudjarwo, Masatoshi Hori, Kiyoshi Sakata, Yoshihiro Urade, Michihiro Takai, Toshikazu Okada,

Renin-Angiotensin System Studies

In isolated rat aorta, endothelin-1 induced contractions at lower concentrations than endothelin-3. The contractile effects were augmented by removing the endothelium. In contrast, endothelin-1 and endothelin-3 at similar concentrations induced endothelium-dependent relaxation in norepinephrine-stimulated aorta. IRL 1038 ([Cys11, Cys15]endothelin-1(11–21); 3 μM) augmented the contractile effects of endothelins only in the presence of the endothelium. IRL 1038 (0.3–3 μM) inhibited the endothelium-dependent relaxation induced by endothelins but not by carbachol. IRL 1038 itself did not change muscle tension. These results suggest that IRL 1038 is a novel antagonist of the ETB receptor responsible for the release of relaxing factor from the vascular endothelium.