Our autonomic nervous system consists of 2 branches:
(1) The Sympathetic Branch, also known as the “Fight or Flight” system, allows you to react fast under stress and is more yang in nature.
(2) The Parasympathetic Branch, also known as the “Rest and Digest” system, relaxes the intestinal sphincters, slows down heart beats, allows you to sleep deeper, and is more yin in nature.
Inflammatory bowel disease is a result of an imbalance in the 2 systems, basically overactivity of the sympathetic branch. The main parasympathetic nerve, the vagus nerve, allows optimal bowel function by reducing the heart rate, and improving the movement of the stomach and intestine. This facilitates better absorption of food and nutrients and improves immune function.
Increased sympathetic activity leads to inflammation via the following mechanisms:
- Endotoxin or proinflammatory cytokines can activate afferent vagal nerve fibers to cause hypothalamic-pituitary-adrenal anti-inflammatory responses.
- Efferent vagal nerve signaling facilitates lymphocyte release via a nicotinic acetylcholine receptor response.
- Direct electrical stimulation of the afferent vagal nerve during lethal endotoxaemia (life threatening high level of toxin in intestines) in rats inhibited TNF (tumor necrosis factor) synthesis in liver, attenuated peak serum TNF amounts, and prevented the development of shock.
Inflammation of the colon can lead to colon mucosa edema, mucosal erosions and ulcers, bowel wall thickening, ulceration, and colon adhesion to adjacent tissues, all of which influence normal movement and lead to pain, constipation or diarrhea.
Vagus nerve stimulation and vagus nerve stimulation + electric acupuncture enhanced vagal activity suppressed sympathetic activity both acutely and chronically. Jin H et al. of John Hopkins University indicated that a 10-day electrical stimulation at ST36 can reduce colon damage by 40 percent. A 6-day vagal nerve stimulation was reported to reduce the colon mucosal damage index by 20 percent, whereas a 5-day treatment was reported to have no effect. The research indicated that sufficient dosage of vagal nerve stimulation or acupuncture is critical to help reduce the colon inflammation and repair the colon tissue damage. This is why acupuncture treatment is needed three times a week for 3 weeks—to balance the sympathetic and parasympathetic nervous system quickly.
In another study that Jin H et al. published in the American Journal of Physiology-Gastrointestinal and Liver Physiology. 2017, vagus nerve stimulation and electrical acupuncture stimulation reduced inflammation in rats with chemical (TNBS) induced colitis. Electrical stimulation on acupoints ST36 and SP6, enhanced vagal nerve activity and consequently improved digestion and apatite. Vagus nerve stimulation for 21 days reduced the inflammation in the colon by 71.1 percent and, when combined with ES stimulation, 79.9 percent.
How Acupuncture and Vagus Nerve Stimulation Reduce Intestinal Inflammation
Inflammation is a result of imbalanced immune activity with an over production of the cytokines IL-1β, and IL-6 and TNFα. TNFα initiates and perpetuates inflammation of the colon and other tissues. Medications that block TNFα are used to treat irritable bowel disease with good results, but medications can cause some serious side effects and at least one-third of patients stop responding to the medication after taking it for a few years.
A 5- to 6-day vagus nerve stimulation treatment and a 10-day electric acupuncture therapy were reported to decrease TNFα, IL-1β, and IL-6 by 20–35 percent in TNBS-treated rats. In this study, more substantial decreases (38–87 percent) were noted in these cytokines with vagus nerve stimulation and vagus nerve stimulation + electrical acupuncture. Researchers found that electrical acupuncture at ST36 enhanced vagal activity and improved gastrointestinal motility.
Clinically we can simply relax more to strengthen the vagus nerve. Our modern society is overly stimulated. Practicing yoga, meditation, or Qi Kong can strengthen your parasympathetic nervous system. If these methods do not work for you, you may want to start with an acupuncture treatment twice a week for 6 weeks. This will balance and reset your nervous system.
Agon A, Hughes DI. Gating of vagal inputs by sciatic afferents in nonspinally projecting neurons in the rat rostral ventrolateral medulla oblongata. Eur J Neurosci 2001; 13:781–792. pmid:11207813
Borovikova LV, Ivanova S, Zhang M, Yang H, Botchkina GI, Watkins LR, et al. Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin. Nature 2000; 405:458–462. pmid:10839541
Guyenet PG. The sympathetic control of blood pressure. Nat Rev Neurosci 2006; 7:335–346. pmid:16760914
Jin H, Guo J, Liu J, Lyu B, Foreman RD, Yin J, Shi Z, Chen JDZ, Am J Physicol: Gastrointes Liver physiol. 2017; Sep 1; 313(3): G192-G202. doi: 10.1152/ajpgi.00254.201
Kavoussi B, Ross BE. The neuroimmune basis of anti-inflammatory acupuncture. Integr Cancer Ther 2007; 6:251–257. pmid:17761638
Zagon A, Hughes DI. Gating of vagal inputs by sciatic afferents in nonspinally projecting neurons in the rat rostral ventrolateral medulla oblongata. Eur J Neurosci 2001; 13:781–792. pmid:11207813
About the Author: Li Zheng Ph.D., L.Ac., Dipl.Ac, Dipl.CH, Dipl.OM is a graduate from the Beijing University of Chinese Medicine with 11 years of formal training, including 6 years of residency. She holds a Ph.D. in neuroscience from the US and is a Harvard Medical School-trained researcher and a professor at the New England School of Acupuncture. Her two practices are located in Needham, MA, and Boca Raton, FL. She has 26 years of clinical experience. To learn more visit her website https://bostonchineseacupuncture.org/.