Aspartate, glutamate, glutamine, glycine and γ-aminobutyric acid in human bioptic neocortical areas: comparison to autoptic tissue

Amino acid concentrations were determined by high performance liquid chromatography in distinct areas of human neocortex of autoptic and bioptic origin. The concentrations in autoptic tissue were similar in all cortical areas which may be explained by postmortem proteolysis, abolishing regional differences seen in bioptic tissue. Aspartate, glutamate, glycine and γ-aminobutyric acid concentrations were lower, but glutamine levels were higher, in biopsied than in autopsied tissue. Glycine and γ-aminobutyric acid concentrations increased with the age of biopsied patients. The differences seen suggest that only amino acid concentrations determined in bioptic tissue may yield a reliable data base for the interpretation of pathological alterations in neocortical biopsies of patients with brain diseases.