Ischemia-induced inhibition of the initiation factor 2α phosphatase activity in the rat brain

Rats were subjected to the standard four-vessel occlusion model of brain transient ischemia for 30 min. Following different recirculation periods, the level of phosphorylation of the initiation factor 2 subunit alpha (eIF2 alpha) and the eIF2 alpha kinase/s and phosphatase/s activity were determined. eIF2 alpha phosphorylation significantly increased very early during reperfusion (10-30 min), recovering at 4 h of reperfusion. Activation of any eIF2 alpha kinases studied during ischemia or reperfusion was not noted. Conversely, eIF2 alpha phosphatase activity significantly decreased at 10-15 min of reperfusion, reaching values even higher than in controls at 2-4 h of reperfusion. Our results support the hypothesis that the reperfusion-induced phosphorylated eIF2 alpha changes are at least a result of the transiently eIF2 alpha phosphatase inhibition. NeuroReport 12:1021-1025 (C) 2001 Lippincott Williams & Wilkins.