Research Notes: The Vagus Nerve

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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.
http://www.ncbi.nlm.nih.gov/pubmed/27010234

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.
http://www.ncbi.nlm.nih.gov/pubmed/26920654

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.
http://www.ncbi.nlm.nih.gov/pubmed/27059884

Chavan, S. S., & Tracey, K. J. (2014). Regulating innate immunity with dopamine and electroacupuncture. Nature Medicine.
https://www.ncbi.nlm.nih.gov/pubmed/24603793

Chavan, S.S., Pavlov, V.A., Tracey, K.J. (2017). Mechanisms and Therapeutic Relevance of Neuro-immune Communication. Immunity.
https://www.ncbi.nlm.nih.gov/pubmed/28636960

Chavan, S.S., Tracey, K.J. (2017). Essential Neuroscience in Immunology. J Immunol.
https://www.ncbi.nlm.nih.gov/pubmed/28416717

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. 
https://www.ncbi.nlm.nih.gov/pubmed/28789470

Graff, D. M., & Mcdonald, M. J. (2016). Auricular Acupuncture for the Treatment of Pediatric Migraines in the Emergency Department. Pediatric Emergency Care.
http://www.ncbi.nlm.nih.gov/pubmed/27139637

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)
https://www.ncbi.nlm.nih.gov/pubmed/27382171

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.
https://www.ncbi.nlm.nih.gov/pubmed/28826627

Lim, H., Kim, M., Lee, C., & Namgung, U. (2016). Anti-Inflammatory Effects of Acupuncture Stimulation via the Vagus Nerve. PLoS ONE.  (OPEN ACCESS)
http://www.ncbi.nlm.nih.gov/pubmed/26991319

Millstine, D., Chen, C., Bauer, B. (2017). Complementary and integrative medicine in the management of headache. BMJ.
https://www.ncbi.nlm.nih.gov/pubmed/28512119

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.
https://www.ncbi.nlm.nih.gov/pubmed/28395101

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.
https://www.ncbi.nlm.nih.gov/pubmed/22568773

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)
https://www.ncbi.nlm.nih.gov/pubmed/19743552

Pavlov, V.A., Tracey, K.J. (2017). Neural regulation of immunity: molecular mechanisms and clinical translation. Nat Neurosci.
https://www.ncbi.nlm.nih.gov/pubmed/28092663

Pereira, M. R., & Leite, P. E. (2016). The Involvement of Parasympathetic and Sympathetic Nerve in the Inflammatory Reflex. Journal of Cellular Physiology.
http://www.ncbi.nlm.nih.gov/pubmed/26754950

Porges, S.W. (2009). The polyvagal theory: new insights into adaptive reactions of the autonomic nervous system. Cleve Clin J Med. (OPEN ACCESS)
https://www.ncbi.nlm.nih.gov/pubmed/19376991

Silva, M. A., & Dorsher, P. T. (2014). Neuroanatomic and Clinical Correspondences: Acupuncture and Vagus Nerve Stimulation. The Journal of Alternative and Complementary Medicine.
http://www.ncbi.nlm.nih.gov/pubmed/24359451

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.
https://www.ncbi.nlm.nih.gov/pubmed/26156114

Torres-Rosas, R., Yehia, G., ... Ulloa, L. (2014). Dopamine mediates vagal modulation of the immune system by electroacupuncture. Nat Med. (OPEN ACCESS)
https://www.ncbi.nlm.nih.gov/pubmed/24562381

Tsai, S., Fox, L. M., Murakami, M., & Tsung, J. W. (2016). Auricular Acupuncture in Emergency Department Treatment of Acute Pain. Annals of Emergency Medicine.
http://www.ncbi.nlm.nih.gov/pubmed/27287548

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.
https://www.ncbi.nlm.nih.gov/pubmed/28803834/

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.
http://www.ncbi.nlm.nih.gov/pubmed/26364692

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.
http://www.ncbi.nlm.nih.gov/pubmed/26381725

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
http://www.ncbi.nlm.nih.gov/pubmed/26364805