[Mediators. Evolution of the concept].

Abstract

The authors review the up-to-date situation in the issue of chemical mediators, acting in the nervous system. Mediators are key intercellular informational molecules found in the brain and peripheral nervous system. Most scientists interpret the term "mediator" rather widely, whereas others define it very strictly and clearly. That is why in neurophysiology the question of what a mediator is has not been answered fully yet. It is clear from the given scientific and historical review, that every new substance (after the first one, acetylcholine) that has had pretensions of being called a mediator, has altered the criteria of it. The authors present the contemporary classification of mediators, belonging to different classes of chemical compounds. Special attention is paid to chemical agents formed in the organism, which have only recently been referred to the class of mediators (gases and D-amino acids).