D-amino acids in the pathogenesis of neurodegenerative diseases and in normal ageing

Recent studies have shown that D-amino acids (DAA) are widely represented in tissues of higher organisms, including man. Specific functions of particular DAA in a healthy body are determined: for instance, D-serine plays an important role in neuroplasticity, memory and learning, while D-aspartate is involved in the development processes and endocrine functions. Pathogenicity of DAA is associated with over-activation of NMDA glutamate receptors, conformational changes of normal protein molecules upon incorporation in the polypeptide chain, and increase inconcentration of reactive oxygen species during oxidase metabolism of DAA. Assessment of the levels of DAA in biological fluids, as well as detection of enzyme activity and mutations of the respective genes may serve as diagnostic markersin a number of the diseases of the central nervous system (Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, etc). Practical interest to the content and the functions of DAA is also related to perspectives of elaborating novel therapeutic strategies aimed at correcting the synthesis/degradation of DAA and modulation of activity of the their receptors.