SELECTIVE ACCELERATION OF ARACHIDONIC-ACID REINCORPORATION INTO BRAINMEMBRANE PHOSPHOLIPID FOLLOWING TRANSIENT ISCHEMIA IN AWAKE GERBIL

Awake gerbils were subjected to 5 min of forebrain ischemia by clampin g the carotid arteries for 5 min and then allowing recirculation. Radi olabeled arachidonic or palmitic acid was infused intravenously for 5 min at the start of recirculation, after which the brains were prepare d for quantitative autoradiography or chemical analysis, Dilution of s pecific activity of the acyl-CoA pool was independently determined for these fatty acids in control gerbils and following 5 min of ischemia and 5 min of reperfusion, Using a quantitative method for measuring re gional in vivo fatty acid incorporation into and turnover within brain phospholipids and determining unlabeled concentrations of acyl-CoAs f ollowing recirculation, it was shown that reperfusion after 5 min of i schemia was accompanied by a threefold increase compared with the cont rol in the rate of reincorporation of unlabeled arachidonate that had been released during ischemia, whereas reincorporation of released pal mitate was not different from the control. Selective and accelerated r eincorporation of arachidonate into brain phospholipids shortly after ischemia may ameliorate specific deleterious effects of arachidonate a nd its metabolites on brain membranes.