Aneurysmal subarachnoid hemorrhage (SAH) afflicts over 30,000 patients a year in the United States. Fifteen percent of those who survive the initial bleeding die or suffer disabilities because of delayed ischemic deficit (stroke) due to vasospasm. Vasospasm is a condition in which the arteries in the brain constrict, not allowing sufficient blood flow and oxygenation. Research on the pharmacological prevention and treatment of vasospasm has resulted in only minimal improvement for this problem.