Role of phospholipase A2 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 have examined the time course of changes in free fatty acid (FFA) levels and cytosolic phospholipase A2 (PLA2) activity during 10 or 20 min periods of four vessel occlusion rat cerebral ischemia followed by reperfusion. Ischemia for a duration of 20 min resulted in a biphasic release of FFA in rat cortical superfusates. There was a rapid elevation 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 thereafter the levels gradually declined, but did not return to basal levels. Measurements by enzymatic assay and Western blot analysis showed a significant increase in the activity and protein levels of cPLA2 during the ischemic periods. These remained elevated at 10 min of reperfusion, but returned to base line levels after 20 min of reperfusion. The possible role of phospholipase A2 (PLA2) in the release of FFA and ischemic injury to the brain is discussed.