Brain-gut axis (GBA)

The **brain-gut axis**—also known as the gut-brain axis or GBA—is not a single molecule or receptor but rather describes the complex bidirectional communication network between the central nervous system (CNS) and the gastrointestinal tract. This system involves neural pathways such as the vagus nerve, endocrine signaling via hormones like those from the hypothalamic-pituitary-adrenal (HPA) axis, immune mediators including cytokines and chemokines, and metabolic products from gut microbiota. The enteric nervous system within the gut acts semi-autonomously but communicates extensively with brain regions involved in emotion and cognition. The microbiota–gut–brain component highlights how microbial metabolites—including neurotransmitters like serotonin and gamma aminobutyric acid—can influence both digestive function and mental health[1][3][4][6]. Disruptions in this network are implicated in various diseases ranging from irritable bowel syndrome to mood disorders[5][7]. However, because it is an integrated physiological pathway rather than a discrete molecular entity or therapeutic target such as an enzyme or receptor protein, it does not fit standard definitions used for drug targets.

Other names

Gut-brain axisMicrobiota–gut–brain axisGut-brain connectionBrain-gut connection