Endothelin-induced intracellular Ca2+ mobilization through its specific receptors in murine peritoneal macrophages.
We studied the presence of specific binding sites for endothelin (ET) and the effect of ET on cytosolic free Ca2+ concentration ([Ca2+]i) in murine thioglycolate-activated peritoneal macrophages. Scatchard analysis for binding experiments using [125I]ET-1 or [125I]ET-3 revealed the existence of a single class of binding sites. The binding parameters (Kd and Bmax) for [125I]ET-1 were almost identical to those for [125I]ET-3. In addition, unlabeled 3 ET isopeptides (ET-1, ET-2 and ET-3) inhibited the specific binding of both ET-1 and ET-3 with similar inhibitory potencies. All 3 ET isopeptides caused an increase in [Ca2+]i in the same dose-dependent manner (0.01-100 nM). These results demonstrate the existence of an ET receptor with the same affinity for all isoforms that mediates the ET-induced intracellular Ca2+ mobilization in murine peritoneal macrophages.
Kishino
J
J
Shionogi Research Laboratories, Shionogi and Co. Ltd., Osaka, Japan.
Hanasaki
K
K
Kato
T
T
Arita
H
H
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000008:administration & dosage / Q000494:pharmacology*; D007249:Inflammation / Q000188:drug therapy; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D010537:Peritoneum; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism; D017466:Receptors, Endothelin; D013864:Thioglycolates / Q000008:administration & dosage / Q000494:pharmacology
D016232:Endothelins; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D013864:Thioglycolates; D002118:Calcium