ERN1 and brain ischemia: After examining the PERK, IRE1, and ATF6 pathways in the brain stem, cerebral cortex, and hippocampus following 10 min global brain ischemia and four hours reperfusion in rats, we observed PERK activation and downstream eIF2α phosphorylation leading to inhibition of protein translation but no increase in CHOP or ATF4, the downstream components of PERK signaling.