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https://hdl.handle.net/11055/35
Title: | Functional estimation of endothelin-1 receptor antagonism by bosentan, macitentan and ambrisentan in human pulmonary and radial arteries in vitro | Authors: | Angus, JA Soeding, PF Hughes, RJA Wright, CE |
Keywords: | Bosentan Endothelin-1 macitentan ambrisentan Human pulmonary artery Human radial artery |
Issue Date: | Jun-2017 | Source: | Angus JA, Soeding PF, Hughes RJA, Wright CE. Functional estimation of endothelin-1 receptor antagonism by bosentan, macitentan and ambrisentan in human pulmonary and radial arteries in vitro. Eur J Pharmacol. 2017; 804:111-116. | Abstract: | Endothelin receptor antagonists are approved for pulmonary arterial hypertension. Development of selective ETA-receptor antagonists over mixed or dual receptor antagonists has depended on a range of receptor binding assays, second messenger assays and functional blood vessel assays. This study compared the 3 clinically-approved endothelin receptor antagonists in assays of human isolated pulmonary and radial arteries in vitro. METHODS: Human isolated pulmonary (i.d. 5.5mm) and human radial (i.d. 3.23mm) artery ring segments were mounted in organ baths for isometric force measurement. Single concentration-contraction curves to endothelin-1 were constructed in the absence or presence of bosentan (1-10µM), macitentan (0.03-0.3µM) or ambrisentan (0.1-1µM). RESULTS: All 3 endothelin antagonists caused competitive rightward shifts in the endothelin-1 concentration-response curves in both arteries. The Clark plot and analysis gave the following pKB values: bosentan, pulmonary artery 6.28±0.13 and radial artery 6.04±0.10; macitentan, pulmonary artery 8.02±0.13 and radial artery 7.49±0.08; and ambrisentan, pulmonary artery 7.38±0.13 and radial artery 6.96±0.10. CONCLUSIONS: Noting the maximum plasma levels attained from recommended oral doses of each antagonist in volunteers, the pKB findings here show that there would be significant antagonism of endothelin-1 contraction in the pulmonary and radial arteries at therapeutic plasma levels. This functional assay confirms in human tissue that much higher plasma concentrations of endothelin-1 receptor antagonists are required to be effective than those predicted from binding or other biochemical assays. | URI: | http://hdl.handle.net/11055/35 | ISSN: | 0014-2999 |
Appears in Collections: | Scholarly and Clinical |
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