After hypoxic/ischemic brain injury, endogenous vasoconstrictor endothelin-1 (ET-1) levels are elevated leading to exacerbated brain injury, but when melatonin is administered in mice stroke models a beneficial neuroprotective effect was observed inhibiting ET-1 (Kilic et al., 2004a; Lo A. C. et al., 2005). This evidence concerns the gene EDN1 and Stroke.