title: Cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel and Na-K-Cl cotransporter NKCC1 isoform mediate the vasorelaxant action of genistein in isolated rat aorta.
abstract: The soy phytoestrogen genistein is a potent vasorelaxant, but its mechanism of action is poorly understood. Here, we used endothelium-denuded rat aorta to investigate the role of the cyclic AMP(cAMP)-activated, cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, and its associated Na-K-Cl cotransporter NKCC1. Isolated, endothelium-denuded rat aorta was contracted with phenylephrine 1 microM, and the vasorelaxant responses to genistein were investigated under conditions where CFTR was inhibited by DPC (diphenylamine-2-carboxylic acid) or glibenclamide (n=6 for compound). Both compounds fully antagonized the vasorelaxant responses to genistein, with IC50=57+/-18 microM and 42+/-11 microM for DPC and glibenclamide respectively. H-89, a selective protein kinase A (PKA) inhibitor, blocked the vasorelaxant responses to genistein. Finally, the NKCC1 inhibitor, bumetanide fully antagonized the vasorelaxant responses to genistein against phenylephrine- or KCl-induced contractions, with IC50=2.0+/-0.2 microM and 1.6+/-0.5 microM, respectively (n=6 for condition). These results strongly suggest that CFTR opening is involved in the vasorelaxant action of genistein, and that cAMP-dependent CFTR phosphorylation and chloride entry via the NKCC1 cotransporter are required for genistein action.
authors.affiliation: Department of Physiology and Pharmacology, School of Medicine, University of Zaragoza, Spain.
authors.forename: Marta S
authors.initials: MS
authors.lastname: Valero
authors.forename: Ricardo P
authors.initials: RP
authors.lastname: Garay
authors.forename: Pilar
authors.initials: P
authors.lastname: Gros
authors.forename: José Octavio
authors.initials: JO
authors.lastname: Alda
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism*; D001224:Aspartic Acid / Q000378:metabolism; D002712:Chlorides / Q000737:chemistry / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D019833:Genistein / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D008297:Male; D009566:Nitrates / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D028021:Sodium-Potassium-Chloride Symporters / Q000737:chemistry*; D064506:Solute Carrier Family 12, Member 2; D062367:ortho-Aminobenzoates / Q000494:pharmacology
chemical_list: C505032:CFTR protein, human; D002712:Chlorides; D009566:Nitrates; C578877:SLC12A2 protein, human; C578879:Slc12a2 protein, rat; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; D062367:ortho-Aminobenzoates; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D001224:Aspartic Acid; C001209:fenamic acid; D019833:Genistein; D000242:Cyclic AMP