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The effect of the ET A receptor antagonist, FR 139317, on [ 125 I]‐ET‐1 binding to the atherosclerotic human coronary artery
Author(s) -
Dashwood Michael R.,
Allen Sean P.,
Luu Thin N.,
Muddle John R.
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb13083.x
Subject(s) - tunica media , tunica , antagonist , tunica intima , receptor , neovascularization , medicine , endothelin receptor , artery , endocrinology , chemistry , ic50 , in vitro , cardiology , anatomy , smooth muscle , biochemistry , angiogenesis , carotid arteries
1 The distribution of [ 125 I]‐endothelin (ET‐1) binding sites on atherosclerotic human epicardial coronary arteries has been studied by in vitro receptor autoradiography. 2 [ 125 I]‐ET‐1 binding was to the tunica media and regions of neovascularization. 3 Competition studies were carried out in the presence of ET‐1 and the ET A receptor antagonist, FR 139317. The IC 50 values for ET‐1 at the tunica media and regions of neovascularization were similar (mean ± s.e.mean of n = 4 patients, 2.5 ± 0.9 n m and 2.9 ± 0.9 n m , respectively) whereas IC 50 values for FR 139317 at regions of neovascularization (607 ± 34 n m ) were significantly higher than those of the tunica media (12.6 ± 2.4 n m ) ( P < 0.0001). 4 These results indicate that ET A receptors are present on the tunica media of the diseased human coronary artery whereas a different ET receptor subtype exists at regions of neovascularization.