EDN1 and subarachnoid hemorrhage: Because ET-1 causes potent and long-lasting vasoconstriction, and there are increased levels of ET-1 in cerebral spinal fluid (CSF) after subarachnoid hemorrhage (SAH) [6,7]; it has been suggested to play an important role in the pathogenesis of delayed cerebral vasospasm following SAH [8] and in cerebral ischemia [9].