THE RELEASE OF BRAIN FREE FATTY ACIDS DURING ISCHAEMIA IN ESSENTIAL FATTY ACID-DEFICIENT RATS

—The release of free fatty acids and especially of free arachidonic acid occurring in rat brain during ischaemia has been studied in essential fatty acid-deficient animals. Free fatty acid levels are lower in essential fatty acid-deficient brains before and especially after 5 min of ischaemia. The percentage of arachidonic acid, in respect of total free fatty acids, is similar in both control and essential fatty acid-deficient brains before ischaemia (0 min), but is greatly reduced in deficient brains in respect of controls after ischaemia (5 min). Total levels of free arachidonic acid are thus greatly reduced after ischaemia in the brain of essential fatty acid-deficient rats. Focussed microwave irradiation of the brain, a technique which instantaneously kills the animals, and which was used for the determination of brain basal levels of free fatty acids and free arachidonic acid, does not per se modify brain lipid and fatty acid composition.