Adaptive and degenerative changes in the neural structures of the olfactory analyzer of animals with decreased olfactory stimulation

Olfactory analyzer receives information about a variety of odorants contained in the surrounding air. Like a number of other neural structures, the olfactory analyzer is capable of undergoing adaptive processes depending on the intensity of sensory stimulation. Numerous experiments on animals demonstrate that the neural structures responsible for olfaction change qualitatively and quantitatively in reduced sensory activation. The objective of this review was to summarize the available literature data on changes in the structure of the olfactory epithelium, olfactory bulb and anterior olfactory nucleus in a decrease or absence of odorant intake as a result of obstruction of one half of the nasal cavity in animals. During the review, we revealed that such neural structures do undergo changes at several levels: macro- and microscopic, biochemical and molecular genetic. In addition, the changes are not only negative and atrophic but also adaptive. It has been shown that the relevant volume of inhaled air is necessary for adequate maturation, functioning and regeneration of the neural structures of the olfactory analyzer.