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.

Decreased plasma alanine and isoleucine in Huntington's disease.

Amino acid concentrations in plasma of patients with Huntington's disease (HD) were determined in 16 patients and 21 age- and sex-matched healthy controls. Alanine and isoleucine were significantly decreased in HD plasma whereas arginine, histidine, leucine, lysine, ornithine, proline, serine, threonine, tyrosine, and valine showed no significant changes. Our findings confirm the decreases of alanine and isoleucine that were described in plasma and cerebrospinal fluid by other investigators. A possible defect in cellular uptake or metabolism of neutral amino acids seems to be a consistent feature of HD.

Simple high-performance liquid chromatographic analysis of free primary amino acid concentrations in rat plasma and cisternal cerebrospinal fluid.

The quantitation of 16 acidic, basic, small and large neutral amino acids was performed using 10-microliters sample aliquots of cisternal cerebrospinal fluid (CSF) and blood plasma of rats. The analytical technique is based upon a two-buffer HPLC system with fluorimetric detection of pre-column derivatized primary amino acids with o-phthaldialdehyde (OPA). A modification of a well established method, the power of the present technique comes from an improved resolution and sensitivity by installing a column heater adjusted to 43 degrees C and strictly reducing any contamination by background amino acids. The analysis is simplified by separating the amino acid derivatives with a linear buffer gradient and less time consuming by the use of a short analytical column with a higher flow-rate. Analytical precision, linearity of response and reproducibility were highly acceptable at both CSF and plasma concentrations of amino acids without changing any of the separation or detection parameters.

Elevated levels of amino acids in the CSF of motor neuron disease patients.

Amino acid levels in the cerebrospinal fluid of patients with motor neuron disease were compared with an age-matched control group receiving diagnostic myelography. Five amino acids were significantly elevated in the cerebrospinal fluid of the motor neuron disease patients compared to the controls. These were isoleucine, glycine, alanine, phenylalanine, and threonine, which were increased by 60, 58, 38, 26, and 25% respectively. A significant increase was also obtained when the amino acids with nonpolar R groups were grouped together (34%). The significance of these findings is discussed in terms of amino acid changes that occur in both normal aging and other neurological conditions.