The COX2 expression or the levels of PGs have been extensively investigated in different cerebral ischemia animal models, such as the temporal and topographic profiles of COX2 expression during 24 h of focal brain ischemia in rats [23], and the levels of TXA2 and PGI2 in rat CA1 hippocampus within 4 h after global cerebral I/R with microdialysis probes [24]. Here, PTGS2 is linked to brain ischemia.