[Effect of phenylmethylsulfonyl fluoride (PMSF) on brain tissue arachidonic acid and extracellular glutamate level in complete cerebral ischemia in rats].

Phenylmethylsulfonyl fluoride (PMSF) is known as phospholipase C inhibitor and also as acetylcholine esterase inhibitor. The purpose of this study is to examine the effect of PMSF on brain tissue arachidonic acid concentrations and extracellular glutamate levels in complete ischemia in rats. Complete cerebral ischemia was induced in rats by decapitation. Tissue concentrations of free arachidonic acid and extracellular levels of glutamate were measured in the striatum after ischemic insult. A focused microwave was irradiated to the head of rat 0, 4, 8 and 12 minutes after ischemic insult. Samples of the striatum were dissected. Arachidonic acids were measured using high-performance liquid chromatography in each sample. A simple sensitive brain microdialysis method and enzymatic cycling technique were employed to determine change of glutamate content in the striatum. PMSF inhibits arachidonic acid release during first 4 minutes of ischemia. PMSF also gets extracellular levels of glutamate unchanged during first 4 minutes of ischemia. It is known that acetylcholine inhibits glutamate release. These results suggest that PMSF inhibits acetylcholine esterase activity in the early stage of complete cerebral ischemia, and induces an inhibition of increase of extracellular glutamate level, and that an inhibition of increase of arachidonic acid is secondary to an inhibition of glutamate receptor rather than an inhibition of phospholipase C activity.