Serotonin: The Link between Gut Microbiome and Brain

Abstract

Serotonin, as a neurotransmitter plays a key role in regulating mood, sleep, appetite, and various physiological processes. Serotonin is closely linked to the microbiome-gut-brain axis, which is a bidirectional communication between the gut and the brain facilitated by the gut microbiome which consists of trillions of microorganisms that inhabit the digestive tract. This connection is a growing area of research and serotonin produced in the gut is being investigated for its potential impact on human personality, mood, and overall health. Microbiome influences serotonin production, serotonin precursor metabolism, serotonin reuptake, and immune system modulation. A balanced microbiome is crucial for regulating homeostasis and stress response and altered gut microbiota composition has been linked to depression, anxiety, bipolar, schizophrenia, stress-related, and autism spectrum disorders. Microbiome-based interventions might help to regulate the immune response, neuroprotection, and neuroplasticity to reduce neuroinflammation and thus prove crucial to modifying the course of major depressive, bipolar, and related disorders where inflammation is evidenced to lead to the progression of illnesses. Microbiome-based interventions such as probiotic supplementation influence the production of neuroactive compounds and have the potential to bridge the treatment gap for Parkinson’s disease, multiple sclerosis, and Alzheimer’s disease and might prove to be a turning point for the treatment of obesity-associated systemic low-level inflammation, whether psychotropic medication related or otherwise. The gut microbiome offers a novel possibility to employ manipulation of the gut microbiota as a non-invasive measure in health and disease, especially at a time when the clinical field of forthcoming psychotropics looks exhausted.