ROLE OF PHOSPHOLIPASE A(2) IN THE RELEASE OF FREE FATTY-ACIDS DURING ISCHEMIA-REPERFUSION IN THE RAT CEREBRAL-CORTEX

Phospholipases are implicated in ischemic damage, In this study, we ha ve examined the time course of changes in free fatty acid (FFA) levels and cytosolic phospholipase A(2) (PLA(2)) activity during 10 or 20 mi n periods of four vessel occlusion rat cerebral ischemia followed by r eperfusion. Ischemia for a duration of 20 min resulted in a biphasic r elease of FFA in rat cortical superfusates. There was a rapid elevatio n in the first 10 min followed by a slower release in the next 10 min. Reperfusion for 10 min resulted in another rapid release of FFA and t hereafter the levels gradually declined, but did not return to basal l evels. Measurements by enzymatic assay and Western blot analysis showe d a significant increase in the activity and protein levels of cPLA(2) during the ischemic periods, These remained elevated at 10 min of rep erfusion, but returned to base line levels after 20 min of reperfusion . The possible role of phospholipase A(2) (PLA(2)) in the release of F FA and ischemic injury to the brain is discussed. (C) 1997 Elsevier Sc ience Ireland Ltd.