title: Bradykinin and vasopressin stimulate Na+-K+-Cl- cotransport in cultured endothelial cells.
abstract: We have characterized a Na+-K+-Cl- cotransporter in vascular endothelial cells (EC) cultured from different blood vessels and species that is inhibited by the diuretics furosemide and bumetanide (50% inhibitory concentration for 86Rb influx approximately 20 microM and 0.5 microM, respectively). Inward 86Rb influx mediated via this pathway is greater than 86Rb influx transported by the Na+-K+ pump in cultured EC from bovine and pig aorta, bovine vena cava, and baboon cephalic vein but not in human umbilical or saphenous vein EC. External Na+ or Cl- -stimulated, ouabain-insensitive 86Rb influx is equal to furosemide or bumetanide-sensitive 86Rb influx. Ouabain-insensitive 22Na influx is also partially inhibited by these drugs and stimulated by increasing external K+ or Cl-. Net Na+ extrusion occurs via the Na+-K+-Cl- cotransporter in the absence of external K+, whereas net Na+ influx occurs at higher external K+ (greater than 1 mM). Maximal concentrations (100 nM) of bradykinin and vasopressin increase the initial rate of bumetanide-sensitive 86Rb influx by approximately 60 and 70% (50% effective concentration approximately 1 and 0.6 nM, respectively). Addition of either ethyleneglycol-bis(beta-aminotethylether)-N,N'-tetraacetic acid or LaCl3 (to block calcium influx) prevents bradykinin-stimulated 86Rb influx. When intracellular calcium is elevated using ionomycin (100 nM), a Ca2+ ionophore, bumetanide-sensitive 86Rb influx increases approximately twofold. In contrast, isoproterenol (100 microM) and forskolin (50 microM), adenylate cyclase stimulators, decrease furosemide-sensitive 86Rb influx.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic; D001692:Biological Transport / Q000187:drug effects; D001920:Bradykinin / Q000494:pharmacology*; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D004727:Endothelium / Q000378:metabolism*; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011868:Radioisotopes; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters; D014471:Umbilical Veins; D014667:Vasopressins / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D002712:Chlorides; D011868:Radioisotopes; D028021:Sodium-Potassium-Chloride Symporters; D014667:Vasopressins; D010042:Ouabain; D005665:Furosemide; D012964:Sodium; D012413:Rubidium; D011188:Potassium; D001920:Bradykinin