Amino acid metabolism in the brain with convulsive disorders. Part 2: The effects of anticonvulsants on convulsions and free amino acid patterns in the brain of El mouse

To elucidate the changes of free amino acid patterns in brains of El mice induced by several anticonvulsants, the free amino acid levels in brains were measured by an amino acid autoanalyzer 24 hours after intraperitoneal injection of PB, PHT or vitamin B6 or subcutaneous injection of ACTH. Compared to the preconvulsion group, the total free amino acid level increased in the ACTH group clearly. In the PB group, the levels of threonine, glutamine, lysine, histidine and homocarnosine increased and that of ornithine decreased; in the PHT group, an increase of glutamine and histidine and a decrease of beta-alanine and ornithine were observed; in the ACTH group, an increase of aspartic acid, threonine, serine, glutamic acid, glutamine, alanine and GABA and a decrease of cystathionine and ornithine were also observed; and in the vitamin B6 group, an increase of taurine and a decrease of cystathionine were recognized. These facts suggest that the sedative activity of these drugs except ACTH might be partially explained by the increase of inhibitory amino acids in the brain, such as glutamine, homocarnosine and taurine, and that of ACTH by the dehydration of the brain, resulting in concentration of many free amino acids.