The role of acupuncture on the autonomic nervous system in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by recurrent abdominal pain, bloating, and irregular bowel movements with complex pathogenesis. Due to its high prevalence and reoccurring symptoms, it seriously impacts patients' quality of life. One of the causes of IBS is turbulence of gastrointestinal motility and intestinal secretion due to dysfunction of the autonomic nervous system (ANS), which the includes the sympathetic nervous system, parasympathetic nervous system, and enteric nervous system. Current research has proven that acupuncture, a traditional Chinese therapy, is useful and effective for treating IBS. The ANS is a key pathway for bidirectional information transmission between the gastrointestinal tract and the central nervous system, which plays an important role in IBS treatment with acupuncture. Research on the mechanisms of acupuncture for IBS is receiving more attention, and the use of contemporary methods has made significant progress. Evidence suggests that acupuncture may mitigate the negative consequences of IBS, as seen by reduced inflammatory signaling, neurotransmitter levels in the colon and central neural tissues, and balanced gut flora. We review and discuss acupuncture's possible mechanisms of action for IBS treatment via the ANS, including modulation of gastrointestinal motility, improvement of visceral hypersensitivity, and innervation of the gut-brain-microbiota axis. Our review demonstrates the available evidence for acupuncture treatment of IBS in clinical settings; however, we also observe that the relationship between the ANS and the gut-brain-microbiota axis is unclear, and further research is needed.