Two distinct types of endothelin receptors are present on chick cardiac membranes.
Competitive displacement experiments of 125I-endothelin (ET)-1, -2, or -3 binding to chick cardiac membranes were performed with unlabeled ET-1, -2, -3, and sarafotoxin S6b (STX) as competitors. 125I-ET-1 and -2 binding was competitively inhibited by increasing concentrations of these unlabeled peptides in the same order; i.e. ET-2 greater than or equal to ET-1 greater than ET-3 greater than STX. In contrast, the order of potency in displacing 125I-ET-3 binding was ET-3 greater than ET-2 greater than or equal to ET-1 greater than STX. Affinity labeling of the membranes by cross-linking with 125I-ET-1 and -2 via disuccinimidyl tartarate yielded one major specific band with an apparent Mr = 53,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography. On the other hand, affinity labeling with 125I-ET-3 showed that two major and one minor bands of Mr = 34,000, 46,000, and 53,000, respectively, were specifically labeled. These results indicate the presence of two distinct types of ET receptors, one of which has higher affinity for ET-1 and -2 than ET-3 and the other is conversely ET-3-preferring.
Watanabe
H
H
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
Miyazaki
H
H
Kondoh
M
M
Masuda
Y
Y
Kimura
S
S
Yanagisawa
M
M
Masaki
T
T
Murakami
K
K
D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D002645:Chickens; D003432:Cross-Linking Reagents / Q000494:pharmacology; D016232:Endothelins; D004730:Endothelium, Vascular / Q000502:physiology*; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D017466:Receptors, Endothelin; D013388:Succinimides / Q000494:pharmacology
D003432:Cross-Linking Reagents; D016232:Endothelins; D010455:Peptides; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D013388:Succinimides; C018052:disuccinimidyl tartarate