Changes in Amino Acid Contents in the Spinal Cord and Brainstem of Rats with Experimental Autoimmune Encephalomyelitis

The effects of experimental autoimmune encephalomyelitis (attack and recovery) on levels of six amino acids have been investigated in nine regions of the Lewis rat spinal cord between segments C3 and Co1 and in the brainstem. Amino acids were analyzed by separation of their 4'-dimethylaminoazobenzene-4-sulfonyl chloride derivatives on a reversed-phase column using a ternary gradient. Glutamate and gamma-aminobutyric acid were reduced by 10-30% in all segments during the attack, whereas taurine, lysine, glutamine, and glycine were all greatly increased (up to 300%). Most values except those of taurine, as well as glutamate in certain segments, returned to normal on recovery. Because some of these compounds have neurotransmitter function, these changes may contribute to the neurological symptoms of experimental autoimmune encephalomyelitis.