Stress and the Gut-Brain Axis

Abstract

The purpose of the review was to study the effects of stress on the gut microbiota. Results and discussion. The gut microbiota forms a complex microbial community that has a significant impact on human health. The composition of the microbiota varies from person to person, and it changes throughout life. It is known that the microbiome can be altered due to diet, various processes, such as inflammation and/or stress. Like all other areas of medicine, microbiology is constantly growing. The gut microbiota lives in a symbiotic relationship with the human host. It is now believed to interact with almost all human organs, including the central nervous system, in the so-called «gut-brain-microbiome axis». Recently, a growing level of research is showing that microbes play a much bigger role in our lives than previously thought, and can have a myriad of effects on how we behave and think, and even on our mental health. The relationship between the brain and the microbiota is bidirectional and includes endocrine, neuronal, immune, and metabolic pathways. The microbiota interacts with the brain through various mechanisms and mediators, including cytokines, short-chain fatty acids, hormones, and neurotransmitters. According to the hypothalamic-pituitary-adrenocortical axis imbalance theory, hormonal imbalances are closely related to psychiatric illness, anxiety, and stress disorders. Therefore, the gut microbiome is closely related to the development and functioning of this axis. The microbiota can influence neurotransmitter levels in a variety of ways, including the secretion of gamma-aminobutyric acid, norepinephrine, dopamine, and serotonin, and can even regulate serotonin synthesis. These neurotransmitters can influence the hormonal status of the body, and the hormones themselves can influence the formation of the qualitative and quantitative composition of the microbiota. Accordingly, a change in the composition of the intestinal microbiota may be responsible for modifying the hormonal levels of the human body. The endocrine environment in the gut can also be modulated through the neuro-enteroendocrine system. Conclusion. Today, it is known that microbiota changes can be associated with several disorders of the nervous system, such as neuropsychiatric, neurodegenerative and neuroinflammatory processes. Research in recent decades has shown that disorders of the nervous system and mood disorders are associated with changes in the balance of neurotransmitters in the brain. Therefore, understanding the role of microbiota in the development and functioning of the brain is of great importance