Tetanus Toxin and Amino Acid Levels in Cat Spinal Cord

Abstract— —The levels of the depressant amino acids found in appreciable amounts in cord extracts—α‐alanine, cystathionine, GABA, glycine and serine—were not significantly influenced by tetanus toxin. This supports the view that the antagonism of spinal inhibition by the toxin is the result of an interference with transmitter release rather than a reduction in the amount of transmitter available for release. The marked increase in aspartic acid levels found in the spinal cord after treatment with tetanus toxin may reflect the association of aspartic acid with the increased activity of spinal excitatory interneurones or the involvement of aspartic acid as a glycine precursor in spinal tissue.