Metabolites from the Gut Microbiota and the Role in the Gut-Brain Axis

The gut microbiota is highly capable of biotransformation, exposing the host to a wide variety of physiologically active compounds. These metabolites participate in signaling between the gastrointestinal tract and the central nervous system and may regulate physiological and pathological processes in the central nervous system. This bidirectional communication can take place in a variety of ways, including binding to receptors in the host brain, stimulating the vagus nerve in the gut, modifying central neurotransmission, and influencing neuroinflam- mation. The purpose of this article is to discuss the mechanism of action of microbial metabolites such as short-chain fatty acids, bile acids, and neurotransmitters in the gut-brain axis and to propose new strategies for treating related neurological illnesses from a gut microbiota regulation perspective.