Endothelin ET(A) and ET(B) receptors in postnatal intestine.
We aimed to characterize endothelin (ET) receptors in the swine intestinal vasculature and to determine ischemia-reperfusion (I/R) effects on these receptors. Saturation and competitive binding assays were performed on mesenteric artery protein membranes from 1- and 40-day-old animals, both control and those subjected to 1 h of partial ischemia followed by 6 h of reperfusion in vivo. Scatchard analysis of saturation binding with (125)I-labeled ET-1 in membranes from endothelium-denuded (E(-)) vessels revealed that the maximum number of binding sites was greater in younger animals. Competitive (125)I-ET-1 binding was significant for a one-site model with ET-1, ET-3, and sarafotoxin S6c (S6c) in membranes from endothelium-intact (E(+)) and E(-) vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. In the presence of the ET(A) receptor antagonist BQ-123, competitive (125)I-ET-1 binding was significant for a one-site model with ET-1 and S6c in membranes from E(+) vessels in both age groups. The maximum number of ET-1 binding sites was significantly greater in younger animals. After I/R, the maximum number of ET-1 binding sites was unchanged. In the presence of BQ-123, specific binding by ET-1 and S6c was eliminated in both age groups after I/R. These results suggest that both ET receptor populations are expressed to a greater degree in younger animals and I/R significantly affects the ET(B) receptor.
Nankervis
C A
CA
Department of Pediatrics, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43205, USA. nankervisc@pediatrics.ohio-state.edu
Dunaway
D J
DJ
Miller
C E
CE
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001667:Binding, Competitive; D065128:Endothelin Receptor Antagonists; D005260:Female; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D008638:Mesenteric Arteries / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000378:metabolism*; D013552:Swine
D065128:Endothelin Receptor Antagonists; D007457:Iodine Radioisotopes; D010456:Peptides, Cyclic; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; C072247:cyclo(Trp-Asp-Pro-Val-Leu)