A novel subtype of endothelin B receptor mediating contraction in swine pulmonary vein

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

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95 Citations (Scopus)


Effects of agonists and antagonists of endothelin (ET) receptors were examined in swine pulmonary artery and vein and in rabbit saphenous vein. ET-1, but not ETB receptor agonists, sarafotoxin S6c (STXc) and IRL 1620, induced contraction in pulmonary artery. This effect was inhibited by the ETA receptor antagonists, BQ-123 and FR139317, but not by the ETB receptor antagonist, IRL 1038. Pulmonary artery precontracted by norepinephrine was relaxed by ET-3 in an endothelium-dependent manner. This relaxation was inhibited by IRL 1038 but not by BQ-123. In pulmonary vein, ET-1, ET-3, STXc and IRL 1620 induced contractions at a similar concentration range. ET-1 induced contraction also in saphenous vein. These contractions were not inhibited by BQ-123, FR139317 or IRL 1038. These results suggest that the isopeptide-selective ETA receptor mediates contraction in swine pulmonary artery whereas the isopeptide-nonselective ETB receptor mediates release of endothelium-derived relaxing factor. In contrast, contractions in the veins may be mediated by a novel subtype of isopeptide-nonselective ETB receptor which is not inhibited by IRL 1038.

Original languageEnglish
Pages (from-to)431-437
Number of pages7
JournalLife Sciences
Issue number5
Publication statusPublished - 1993
Externally publishedYes


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