title: Increased nitroglycerin-induced relaxation by genistein in rat aortic rings.
abstract: The effect of genistein, a tyrosine kinase inhibitor, on nitroglycerin-induced relaxation was examined in rat aortic rings contracted by phenylephrine. In rat aortic rings, genistein (10(-5) M and 3x10(-5) M), a tyrosine kinase inhibitor, but not daidzein, an analogue of genistein, increased relaxation induced by nitroglycerin in a concentration-dependent manner. Iberiotoxin, an inhibitor of Ca2+ -activated K+ channels, inhibited the relaxation induced by nitroglycerin, but it did not affect the effect of genistein. Glibenclamide, an inhibitor of ATP-sensitive K+ channels, did not affect the relaxation induced by nitroglycerin. Theophylline, an inhibitor of cyclic AMP-dependent phosphodiesterase, increased the relaxation induced by nitroglycerin, and genistein (10(-5) M) failed to affect the relaxation induced by nitroglycerin in the presence of theophylline. Genistein also inhibited the activity of cyclic AMP-dependent phosphodiesterase. In addition, 6-[4-(4'-pyridyl)amino phenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride, an inhibitor of cyclic GMP-inhibitable cyclic AMP phosphodiesterase, inhibited the relaxation induced by nitroglycerin. These results suggest that, in the rat aortic rings, genistein inhibits cyclic AMP-dependent phosphodiesterase activities, resulting in the increase of the relaxation induced by nitroglycerin.
authors.affiliation: Department of Pharmacology, University of Hawaii School of Medicine, Honolulu 96822, USA.
authors.forename: N
authors.initials: N
authors.lastname: Satake
authors.forename: M
authors.initials: M
authors.lastname: Imanishi
authors.forename: S
authors.initials: S
authors.lastname: Shibata
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects; D000242:Cyclic AMP / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology*; D005905:Glyburide / Q000494:pharmacology; D007529:Isoflavones / Q000494:pharmacology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D005996:Nitroglycerin / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013806:Theophylline / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D007529:Isoflavones; D010455:Peptides; D011724:Pyridazines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; C004742:daidzein; C064719:iberiotoxin; C052228:MCI 154; D013806:Theophylline; D019833:Genistein; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases; D010727:Phosphoric Diester Hydrolases; D005996:Nitroglycerin; D005905:Glyburide