Inhibitory and excitatory amino acids in cerebrospinal fluid of neurolathyrism patients, a highly prevalent motorneurone disease.

Neurolathyrism is caused by overconsumption of seeds containing 3-N-oxalyl-L-2,3-diaminopropanoic acid (beta-ODAP). Amino acids levels of cerebrospinal fluid (CSF) were studied in 50 patients with neurolathyrism and 12 healthy volunteers. The levels of excitatory amino acids glutamate and aspartate were 281% and 71% respectively of control values. The concentration of inhibitory amino acids glycine and taurine were 277% and 198% respectively of the levels in CSF from control individuals. There was a significant correlation between the level of glycine and the duration of the disease. We also found increased levels of threonine, serine and alanine. In contrast to reports on other motor neurone diseases where an increase of isoleucine was observed we found a significant decrease of isoleucine. The results suggest a disturbance of amino acid metabolism due to excitotoxic damages caused by beta-ODAP, a dietary excitatory amino acid.