Gamma-aminobutyric acid, other amino acids and electrolytes in relation to physiological and metabolic activities of brain.

The uptake of gamma-aminobutyric acid (GABA) by brain slices from a balanced saline medium was found to be maximal with 3.6 millimolar potassium in the medium and was decreased by omission of potassium or calcium or by increasing the potassium concentration. No marked effects of GABA on potassium-stimulated oxygen uptake or on electrolyte accumulation or binding were found. Intraperitoneally-administered large volumes of hyperosmotic solutions of amine acids, sucrose or succinate delayed or protected against convulsions induced in rats by high oxygen pressure, picrotoxin or pentylenetetrazol. The effect was found to be associated with increased serum osmolarity and consequent dehydration of the brain. Labelled amino acids and other substances were collected from small areas of the exposed cerebral cortex of animals after subcutaneous injection of or perfusion of the brain with labelled glucose solution. No evidence for the presence of appreciable amounts of gamma-amino- beta-hydroxybutyric acid in rat brain could be obtained; beta-alanine was shown to be definitely present