The effects of diaspirin cross-linked hemoglobin on the tone of human saphenous vein.
Diaspirin cross-linked hemoglobin (DCL-Hb), when infused into animals, causes vasoconstriction thought to be caused by nitric oxide (NO) binding by the hemoglobin molecule. The purpose of this study was to ascertain whether DCL-Hb causes vasoconstriction in human saphenous vein taken from patients undergoing myocardial revascularization and whether NO scavenging is the mechanism. The direct effect of DCL-Hb on saphenous vein tone was tested by adding increasing concentrations (10(-8) to 10(-5)M) of the drug. In an additional series of experiments, the influence of DCL-Hb on the dilator response to endothelial dependent and independent vasodilators was tested. This was achieved by attempting either to reverse the effects of acetylcholine, sodium nitroprusside, or S-nitrosylglutathione with prior incubation with DCL-Hb or to inhibit the dilator response in vessels preconstricted with 10(-6)M norepinephrine. There was no effect of DCL-Hb alone on saphenous vein tone. DCL-Hb significantly reduced vasodilatation with all vasodilators (P < 0.05). After maximal relaxation with sodium nitroprusside and s-nitrosylglutathione, there was significant vasoconstriction with DCL-Hb at concentrations larger than 10(-6)M, (P < 0.05). The authors conclude that DCL-Hb does not constrict human saphenous vein but can affect vessel tone by reversal of the effect of endogenously or exogenously released NO.
Forrest
M R
MR
Department of Anaesthesia, Harefield and Royal Brompton NHS Trust, Harefield, London, UK. mforrest50@hotmail.com
Chester
A H
AH
Royston
D
D
D000109:Acetylcholine / Q000494:pharmacology; D001241:Aspirin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001802:Blood Substitutes / Q000494:pharmacology*; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology; D006454:Hemoglobins / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D026422:S-Nitrosoglutathione; D012501:Saphenous Vein / Q000187:drug effects* / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects*
D001802:Blood Substitutes; D006454:Hemoglobins; D009603:Nitroso Compounds; D009599:Nitroprusside; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; C083478:diaspirin-cross-linked hemoglobin; D005978:Glutathione; D000109:Acetylcholine; D001241:Aspirin