The present study has investigated the role of Na+/H+ exchanger-1 (NHE-1) during cerebrovascular endothelial dysfunction during ischemia in a rat cerebral ischemia model in vivo and in mouse brain microvascular endothelial cells (bEnd.3 cells) in vitro. This study shows that specific inhibition of NHE-1 by sabiporide, a well-known NHE-1inhibitor, ameliorates brain edema in vivo, and attenuates cerebrovascular endothelial hyperpermeability induced by ischemia in vivo and in vitro. Occludin and Zonular Occludens-1 (ZO-1) were found to be damaged in the ischemic rat brain, but the inhibition of NHE-1 reversed these damages. Furthermore, during aglycemic hypoxia in bEnd.3 cells, the subcellular distributions of occludin and ZO-1 were found to be altered, but these changes were also reversed by NHE-1 inhibition. Sabiporide also inhibited aglycemic hypoxia-induced increases in intracellular Ca2+ levels. These findings suggest that NHE-1 plays a critical role during ischemia-induced cerebrovascular hyperpermeability and TJs alteration, and that NHE-1 inhibition can be therapeutic target to protect against cerebrovascular dysfunction during brain ischemia.