Autoradiographic localization of endothelin-1 binding sites in the cardiovascular and respiratory systems.
Specific high-affinity binding sites for endothelin-1 (ET-1) have been demonstrated in peripheral tissues using the technique of in vitro receptor autoradiography. Binding was time dependent and saturable and inhibited by coincubation with an excess of unlabeled ET-1 but resistant to dissociation. Binding sites were localized to blood vessels of all sizes including coronary arteries, intrapulmonary vessels, and intrarenal and intrasplenic arteries. In addition, high-affinity binding sites were identified on airway smooth muscle, over alveolar septa, and on nerve trunks. Scatchard analysis of the data revealed a Bmax of 250 amol/mm2 and a Kd of 0.1 nM for the binding of rat tracheal smooth muscle, with similar values for porcine coronary artery. The localization of binding sites is consistent with the known effects of ET-1 and suggests a direct action on specific receptors.
Power
R F
RF
Department of Histochemistry, Hammersmith Hospital, London, England.
Wharton
J
J
Zhao
Y
Y
Bloom
S R
SR
Polak
J M
JM
D000818:Animals; D001345:Autoradiography; D002319:Cardiovascular System / Q000378:metabolism*; D016232:Endothelins; D006168:Guinea Pigs; D006801:Humans; D007457:Iodine Radioisotopes; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017466:Receptors, Endothelin; D012137:Respiratory System / Q000378:metabolism*; D013552:Swine
D016232:Endothelins; D007457:Iodine Radioisotopes; D010455:Peptides; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin