Amino acids in human epileptogenic foci.

Free amino compounds were measured in 16 rapidly frozen epileptogenic foci excised from temporal or frontal cortex of nine patients with focal epilepsy, and in single cortical biopsy specimens obtained from 16 nonepileptic patients. Unlike the findings of a previous study, glutamic and aspartic acids were not diminished in the foci, nor was there a decrease in gamma-aminobutyric acid (GABA) or taurine levels. Glycine content was markedly elevated in two of 16 epileptogenic foci. These results do not suggest that deficiencies of GABA or of taurine, amino acids that may act physiologically as inhibitory neurotransmitters or modulators of inhibition, are causes of focal epilepsy, nor do they provide a logical basis for clinical trials of taurine in treatment of human epilepsy.