“Removal of endothelium (P < 0.05), pretreatment with a nitric oxide (NO) synthesis inhibitor (l-N(G)-monomethylarginine, 200 microM, P < 0.001), or pretreatment with a hydroxyl radical ((*)OH) scavenger mannitol , 10 mM, P < 0.001) significantly attenuated contraction potentiated by Hcy plus Fe(2+).”