title: Glutathione causes coronary vasodilation via a nitric oxide- and soluble guanylate cyclase-dependent mechanism.
abstract: The actions of thiols on coronary vascular tone in the intact heart are unknown. Glutathione (GSH), glutathione disulfide (GSSG), and L-cysteine (10-1,000 microM each) and GSH ethyl ester (3-300 microM) were infused into isolated rat hearts perfused with Krebs buffer at a constant pressure by the Langendorff method. GSH, GSSG, and GSH ethyl ester, but not L-cysteine, caused a concentration-dependent increase in coronary flow with the following order of potency: GSH ethyl ester > GSH = GSSG. The nitric oxide synthase inhibitor NG-monomethyl-L-arginine (300 microM), prevented the increase in coronary flow with GSH and attenuated that with GSSG (300 microM each). The vasodilation with GSH or GSSG and the associated increase in myocardial guanosine 3',5'-cyclic monophosphate were abolished by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (a specific inhibitor of soluble guanylate cyclase) at 1 and 3 microM, respectively. The vasodilator action of GSH was abolished by superoxide dismutase (50 U/ml). Inhibition of GSH reductase abolished GSSG-induced vasodilation. Neither glibenclamide (1 microM) nor indomethacin (4 microM) affected the vasodilator action of GSH and GSSG. We conclude that GSH and GSSG cause coronary vasodilation that is mediated by a nitric oxide- and guanylate cyclase-dependent mechanism, possibly mediated by the reaction between GSH and peroxynitrite to form S-nitrosoglutathione, a nitric oxide donor.
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, Canada.
authors.forename: P Y
authors.initials: PY
authors.lastname: Cheung
authors.forename: R
authors.initials: R
authors.lastname: Schulz
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002330:Carmustine / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology*; D019803:Glutathione Disulfide; D005905:Glyburide / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D010069:Oxadiazoles / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013237:Stereoisomerism; D013482:Superoxide Dismutase / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D016277:Ventricular Function, Left / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology*
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D004791:Enzyme Inhibitors; D010069:Oxadiazoles; D011810:Quinoxalines; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D006162:Guanylate Cyclase; D005978:Glutathione; D005905:Glyburide; D002330:Carmustine; D019803:Glutathione Disulfide; D007213:Indomethacin