Studies on Amino Acids Pattern in Amyotrophic Lateral Sclerosis

ABSTRACT

Recent researches on ALS pathogenesis are focusing on abnormal immunological factors, excitotoxic substances, neurotrophic factors, and oxidative stress. It is well known that glutamate and aspartate are major putative excitatory neurotransmitters and possess excitotoxic properties that lead to neuronal death. In this study the authors checked the plasma level of amino acids in ALS and control groups and tried to understand any association between excitotoxic amino acids and sporadic ALS. The concentration of amino acids was measured by the HPLC method in the fasting plasma of fifteen ALS and nine control subjects. When we evaluated 19 amino acids or their metabolites, none showed significant difference between ALS and control groups. The mean concentrations of glutamic acid in ALS and control groups were 42.3+26.7 mmol/L and 57.4+17.0 mmol/L respectively, which showed no significant difference (p>O. 05). It was not possible to compare the level of aspartic acid in ALS and control groups as the levels were very low in individuals of both groups. In conclusion, authors could not note any significant correlations between sporadic ALS and excitotoxic substances, such as glutamate and aspartate. However, further studies m the excitotoxic levels in cerebrospinal fluid, spinal cord and brain, could be helpful to understand the overexcitation character of motor neuron by excitatory amino acids.