Figure 2: Relaxation responses induced by EOK (10–600 μg/mL) in endothelium-intact rat aortic rings precontracted with phenylephrine (PE, 1 μM) in the presence or absence (control) of Nω-nitro-L-arginine methyl ester (L-NAME, 10 μM) (a) or methylene blue (MB, 10 μM) (b) in Krebs-Henseleit solution. The relaxant effects of EOK on isolated rat aortic rings were calculated as a percentage of the contraction in response to PE. Control groups were not treated with L-NAME or MB. Values are expressed as mean ± SEM ( ). * and ** versus control.