AKT1 and brain ischemia: Since various inhibitors or activators of the Akt-mTOR-S6 axis affected the degree of BBB disruption and neuronal survival within a few hours of cerebral ischemia-reperfusion [22,25,26,27,28], we conducted this study to examine whether an acute elevation of leucine levels in the brain can confer neuroprotection during the early phase of ischemia-reperfusion within a few hours of stroke.