Figure 1.

Concentration-response curves showing the changes in tone induced by (a) authentic Cu/Zn superoxide dismutase (Cu/Zn SOD), (b) CuSO₄, and (c) CuDIPS on phenylephrine-contracted, endothelium-containing rings of rat aorta (control). The effects of pretreatment with L-NAME (100 μM; 30 min) and of endothelial removal (−EC) on these changes are also shown. Each point is the mean±s.e.mean of 5–8 observations. ^*P<0.05, ^**P<0.005, and ^***P<0.001 indicate a significant difference following treatment with L-NAME. #P<0.05 and ###P<0.001 indicate a significant difference following endothelial removal. For clarity, levels of statistical significance shown in (a) are for the highest concentration of Cu/Zn SOD only.