title: Allosteric inhibition of [(125I)] ET-1 binding to ET(A) receptors by aldoxime and hydroxamic acid derivatives.
abstract: Endothelin-1 (ET-1), a potent vasoconstrictor peptide, exerts its physiological effects by binding and activating specific G protein-coupled receptors, named ET(A) and ET(B). An unique property of ET-1 is its ability to bind almost irreversibly to its receptors. Aspirin and salicylic acid (SA) are allosteric inhibitors of ET-1 binding to ET(A) receptors. Dihalogenated derivatives of SA have been identified as more potent allosteric inhibitors than aspirin. In this study, disubstituted benzohydroxamic acid, benzaldoximes and dihalosalicylic acid dimers were synthesized and tested as inhibitors of [(125)I]ET-1 binding to ET(A) receptors in rat embryonic cardiomyocyte (H9c2 cell) membranes. Some dihalosalicylic acid dimers 2h showed good inhibitory activity, the most active compounds are the hydroxamic acids derived from anthranilic acid. Among these compounds, the 3, 5-diiodo-2-aminobenzohydroxamic acid e compound 2a is three-folds more potent as inhibitor of [(125I)] ET-1 binding to ET(A) receptors than the 3; 5-diiodosalicylic acid reported in literature. Most aryl aldoximes in this study were biologically inactive as inhibitors of [(125I)] ET-1 binding to ET(A) receptors.
authors.affiliation: Department of Pharmaceutical Chemistry, Garyounis University, Benghazi, Libya. mabuajila@yahoo.ca
authors.forename: Musa
authors.initials: M
authors.lastname: Ahmed
authors.forename: Susanna
authors.initials: S
authors.lastname: Nencetti
authors.forename: Maria R
authors.initials: MR
authors.lastname: Mazzoni
authors.forename: Francesca
authors.initials: F
authors.lastname: Porchia
authors.forename: Federica
authors.initials: F
authors.lastname: Antonelli
authors.forename: Annalina
authors.initials: A
authors.lastname: Lapucci
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000818:Animals; D002460:Cell Line; D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism*; D006877:Hydroxamic Acids / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D007457:Iodine Radioisotopes; D015394:Molecular Structure; D010091:Oximes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D051381:Rats; D044022:Receptor, Endothelin A / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D065130:Endothelin A Receptor Antagonists; D019332:Endothelin-1; D006877:Hydroxamic Acids; D007457:Iodine Radioisotopes; D010091:Oximes; D044022:Receptor, Endothelin A