Hexose and pentose phosphates in brain during convulsions1

The Metabolism of glucose via glycolysis and the citric acid cycle represents the chief source of energy supplies in the brain. However, enzymes for the metabolism of glucose via the hexosemonophosphate (O'Neill, Simon and Shreeve, 1965) and pentose phosphate (Dreyfus and Moniz, 1962) pathway are also present in brain. A major difficulty in studying intermediates of the hexose and pentose phosphate pathway in brain is their extremely low absolute levels. Recently, fluorimetric, enzymic assays for these substrates have been developed (Kauffman, Brown, Passonneau and Lowry, 1969), and these assays, combined with rapid freezing techniques (Lowry, Passonneau, Hasselberger and Schulz, 1964) have made it possible to study these intermediates in brains of mice. Electrically‐induced tonic‐clonic convulsions are associated with a striking increase in metabolic rate in brain, but phenobarbitone minimizes changes in metabolic rate during convulsions (King, Lowry, Passonneau and Venson, 1967). In order to determine whether or not levels of hexose and pentose phosphates are altered under these conditions, assays for these substrates have been carried out in brains of convulsing mice with or without administration of phénobarbital prior to stimulus.