Evolution, possibilities and prospects in the application of methods for the assessment of pyridine nucleotides pool for studying the mechanisms of brain plasticity in normal and pathological conditions

Nicotinamide adenine dinucleotide and its derivatives – NAD+, NADP+, NADH, NADPH – play an important role in cell metabolism, act as substrates or cofactors for a large number of enzymes involved in the regulation of replication, DNA repair, maintenance of calcium homeostasis in cells, biosynthetic processes and energy production mechanisms. Changes in the ratio of oxidized and reduced forms of pyridine nucleotides accompanies the development of oxidative and reductive stress, that significantly contribute to cell damage and induction of adaptive response. Currently, huge number of protocols aimed at quantitative or qualitative assessment of the pyridine nucleotide pool are in use, but all of them have their limitations associated with sample preparation processes, difficulties in the metabolite spectrum assessment, and complexity of data interpretation. Measuring pyridine nucleotide levels is relevant in the study of (patho)physiological regulatory mechanisms of cell functional activity and intercellular communication. This is of particular relevance when studying the mechanisms of plasticity of the central nervous system in health and disease, since significant changes in the pools of pyridine nucleotides in cells are evident in neurodevelopmental disorders, neurodegeneration, and aging. Simple and reliable non-invasive methods for measuring the levels of NAD+ and NADH are necessary to assess the brain cells metabolism with diagnostic and research purposes. The goal of this review is to analyze in a comparative aspect the main methods for measuring the levels of oxidized and reduced pyridine nucleotides in cells and to identify the key principles of their application for the correct interpretation of the data obtained, including those used for the study of the central nervous system.