Efflux of gamma-aminobutyric acid from and appearance of free arachidonic acid inside synaptosomes.
When synaptosomes were depolarized in the presence of Ca2+, or when Ca2+ was added to synaptosomes pretreated with Ca2+ ionophore (A23187), free arachidonic acid was clearly increased within synaptosomes, and at the same time an efflux of gamma-aminobutyric acid from synaptosomes was observed. Moreover, when synaptosomes labelled with [14C]arachidonic acid were depolarized in the presence of Ca2+, there was a significant decrease in the radioactivity of the fatty acid of phosphatidylinositol and phosphatidylcholine. Exogenously added arachidonic acid, but not other fatty acids, stimulated the efflux of gamma-aminobutyric acid in the absence of Ca2+. These observations suggest that the release of arachidonic acid from phospholipids is an intrinsic part of the biochemical mechanism that modulates the gamma-aminobutyric acid efflux.
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D051379:Mice; D010743:Phospholipids / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D001095:Arachidonic Acids; D008563:Membrane Lipids; D010743:Phospholipids; D016718:Arachidonic Acid; D000001:Calcimycin; D005680:gamma-Aminobutyric Acid; D011188:Potassium; D002118:Calcium