Lecithinized superoxide dismutase induces vasodilation; Evidence of directcontribution of superoxide anions to modulating vascular tone

The purpose of this study was to examine the role of superoxide anions in m odulating the vascular tone. The effects of unmodified and lecithinized sup eroxide dismutase (SOD) on vascular tone were determined in aortic ring pre parations of mice. In lecithinized SOD, 4 molecules of a phosphatidylcholin e derivative were covalently bound to each dimer of recombinant human coppe r-zinc SOD to facilitate tissue accumulation. Unmodified SOD did not change vascular tone. However, lecithinized SOD induced dose-dependent vasodilati on of aortic ring preparations. The pretreatment with N-G-nitro-L-arginine methylester (L-NAME) 10(-4) mol/L abolished the vasodilation induced by lec ithinized SOD. The results of this study indicate that superoxide anions pl ay a prominent role in modulating the vascular tone by enhancing the breakd own of nitric oxide. (C) 1998 Elsevier Science Inc.