Isolated cerebral cortex: Changes in levels of glutamic acid, glutamine, aspartic acid, and γ-aminobutyric acid

Cerebral cortex of the cat was isolated by undercutting from its neuronal connections with the rest of the brain but not from its blood supply. The cerebral cortex responds to such treatment by changes in electrophysiological activity as well as by decreases in levels of glutamate, aspartate, and γ-aminobutyrate and a rise in glutamine suggesting the establishment of a new steady state for these amino acids. These biochemical changes are most prominent approximately one week after isolation of the tissue. There is no clear time correlation between the development of the electrophysiological abnormality and the tissue levels of these amino acids.