Research Notes: The Vagus Nerve

The Wandering Nerve

The course and distribution of the glossopharyngeal, vagus, and accessory nerves.

The course and distribution of the glossopharyngeal, vagus, and accessory nerves.

The Vagus nerve is captain of the parasympathetic nervous system. It serves to regulates heart rate, bronchoconstriction, digestion, and the innate immune response.

This post contains some notes and links related to the vagus nerve.

The Polyvagal Theory

The Polyvagal Theory proposed by Dr. Stephen Porges specifies two functionally distinct branches of the vagus nerve. The more primitive branch elicits immobilization behaviors, whereas the more evolved branch is linked to social communication and self-soothing behaviors.

These neural pathways regulate autonomic state and has implications for the stress response such as heart rate and cortisol level.

Electric Stimulation of the Vagus Nerve Reduces Inflammation

Breaking new ground, Kevin Tracey was the first to demonstrate that stimulating the vagus nerve can significantly reduce inflammation. His group released a very promising study that looked at the effects of vagus nerve stimulation for Rheumatoid Arthritis. This was a landmark study that demonstrated for the first time that vagus nerve stimulation inhibits Tumor Necrosis Factor (TNF) production in spleen and attenuates inflammation in humans. 

This gets me excited for upcoming technological advances, that may change the way we view and treat diseases. Essentially, this paper proposes that action potentials carried in the vagus nerve suppress cytokine production, this is termed the "inflammatory reflex".

Auricular Branch of The Vagus Nerve

Research on the vagus nerve and the inflammatory reflex may have implications for medical acupuncture, a therapeutic approach in which acupuncture needles are inserted into anatomically defined sites, and stimulated manually or with electricity. The study referenced above uses an invasive devise to activate this inflammatory response, but Tracey has also been looking at using electro-acupuncture to activate this response through auricular branches of the vagus nerve

The Vagus Nerve Initiates Your Body’s Relaxation Response

Stimulation of the auricular branch of the vagus nerve (the inner conch of the ear) is also being investigated as part of a non-pharmacological pain management strategy and things look promising (Murakami et al. 2017).

More to Explore

Bonaz, B., Sinniger, V., & Pellissier, S. (2016). Vagal tone: Effects on sensitivity, motility, and inflammation. Neurogastroenterology & Motility.

Bonaz, B., Sinniger, V., Hoffmann, D., Clarençon, D., Mathieu, N., Dantzer, C., . . . Pellissier, S. (2016). Chronic vagus nerve stimulation in Crohn's disease: A 6-month follow-up pilot study. Neurogastroenterology & Motility.

Bonaz, B., Sinniger, V., & Pellissier, S. (2016). Anti-inflammatory properties of the vagus nerve: Potential therapeutic implications of vagus nerve stimulation. The Journal of Physiology.

Chavan, S. S., & Tracey, K. J. (2014). Regulating innate immunity with dopamine and electroacupuncture. Nature Medicine.

Chavan, S.S., Pavlov, V.A., Tracey, K.J. (2017). Mechanisms and Therapeutic Relevance of Neuro-immune Communication. Immunity.

Chavan, S.S., Tracey, K.J. (2017). Essential Neuroscience in Immunology. J Immunol.

Duchesne, E., Dufresne, S.S., Dumont, N.A. (2017). Impact of Inflammation and Anti-inflammatory Modalities on Skeletal Muscle Healing: From Fundamental Research to the Clinic. Phys Ther.

Graff, D. M., & Mcdonald, M. J. (2016). Auricular Acupuncture for the Treatment of Pediatric Migraines in the Emergency Department. Pediatric Emergency Care.

Koopman, F. A., Chavan, S. S., Miljko, S., Grazio, S., Sokolovic, S., Schuurman, P. R., . . . Tak, P. P. (2016). Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis. Proceedings of the National Academy of Sciences. (OPEN ACCESS)

Kovacic, K., Hainsworth, K., Sood, M., ... Miranda, A. (2017). Neurostimulation for abdominal pain-related functional gastrointestinal disorders in adolescents: a randomised, double-blind, sham-controlled trial. Lancet Gastroenterol Hepatol.

Lim, H., Kim, M., Lee, C., & Namgung, U. (2016). Anti-Inflammatory Effects of Acupuncture Stimulation via the Vagus Nerve. PLoS ONE.  (OPEN ACCESS)

Millstine, D., Chen, C., Bauer, B. (2017). Complementary and integrative medicine in the management of headache. BMJ.

Murakami, M., Fox, L., Dijkers, M.P. (2017). Ear Acupuncture for Immediate Pain Relief-A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Pain Med.

Napadow, V., Edwards, R. R., Cahalan, C. M., Mensing, G., Greenbaum, S., Valovska, A., . . . Wasan, A. D. (2012). Evoked Pain Analgesia in Chronic Pelvic Pain Patients Using Respiratory-Gated Auricular Vagal Afferent Nerve Stimulation. Pain Medicine.

Oke, S.L., Tracey, K.J. (2009) The inflammatory reflex and the role of complementary and alternative medical therapies. Ann N Y Acad Sci. (OPEN ACCESS)

Pavlov, V.A., Tracey, K.J. (2017). Neural regulation of immunity: molecular mechanisms and clinical translation. Nat Neurosci.

Pereira, M. R., & Leite, P. E. (2016). The Involvement of Parasympathetic and Sympathetic Nerve in the Inflammatory Reflex. Journal of Cellular Physiology.

Porges, S.W. (2009). The polyvagal theory: new insights into adaptive reactions of the autonomic nervous system. Cleve Clin J Med. (OPEN ACCESS)

Silva, M. A., & Dorsher, P. T. (2014). Neuroanatomic and Clinical Correspondences: Acupuncture and Vagus Nerve Stimulation. The Journal of Alternative and Complementary Medicine.

Straube, A., Ellrich, J., Eren, O., Blum, B., & Ruscheweyh, R. (2015). Treatment of chronic migraine with transcutaneous stimulation of the auricular branch of the vagal nerve (auricular t-VNS): A randomized, monocentric clinical trial. The Journal of Headache and Pain.

Torres-Rosas, R., Yehia, G., ... Ulloa, L. (2014). Dopamine mediates vagal modulation of the immune system by electroacupuncture. Nat Med. (OPEN ACCESS)

Tsai, S., Fox, L. M., Murakami, M., & Tsung, J. W. (2016). Auricular Acupuncture in Emergency Department Treatment of Acute Pain. Annals of Emergency Medicine.

Usichenko, T., Hacker, H., Lotze, M. (2017). Transcutaneous auricular vagal nerve stimulation (taVNS) might be a mechanism behind the analgesic effects of auricular acupuncture. Brain Stimul.

Yuan, H., & Silberstein, S. D. (2015). Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part I. Headache: The Journal of Head and Face Pain.

Yuan, H., & Silberstein, S. D. (2015). Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part II. Headache: The Journal of Head and Face Pain.

Yuan, H., & Silberstein, S. D. (2015). Vagus Nerve and Vagus Nerve Stimulation, a Comprehensive Review: Part III. Headache: The Journal of Head and Face Pain