Everyday in practice, we see our patients achieve amazing results with the help of our treatments. That said, many of us have been trained using models such as TCM, Zang Fu, and Five Elements that are completely foreign to the cultures in which we live and practice. As such, there’s a growing awareness of the need to be able to explain our treatments and results in biomedical terms. We need to be able to answer the question: “So, how does acupuncture work?” in a way that will make sense to the asker.
Growing research into acupuncture mechanisms is starting to provide useful answers for us. It is unlikely that basic science research could ever explain the entirety of ‘acupuncture’, simply because it tends to look at one tiny piece of the health puzzle at a time without fully integrating this information back into the whole. Biochemistry and physics tend to study and label “states” whereas part of the genius of our models is that they understand processes and relationships. We understood the role of digestion in mood and emotions in physiology well before modern research started exploring these connections, because of our relational lens.
Thus, we can use the discoveries of acupuncture mechanism research pragmatically, to foster confidence and support from our patients, our medical colleagues and our communities. Many who have looked into this have their pet theories, focusing on various biochemicals and physical structures in the body as the direct correlate of concepts described in the Nan Jing. The challenge here is that when we provide a stimulus through acupuncture needling, on the microscopic level, many things change at once. If we zoom in on one particular molecule, whether it be nitric oxide, serotonin, or cortisol, we can say, ‘Look! Acupuncture made it change! This is how acupuncture works!’ But often these perspectives aren’t really telling us if we’re looking at cause or effect (or both!).
However, there is one particular physically induced biochemical pathway that may be helpful for us to zero in on. In the 1970’s, a researcher by the name of Geoffrey Burnstock discovered a previously unknown family of neurotransmitters called ‘purines.’ Purines, such as ATP and adenosine, had been previously discovered, but their central role in neurotransmission and regulation was a completely new concept. However, we now know that purinergic signaling evolved pretty much when life on earth did and is even older than the nervous system.
Purinergic signaling is triggered in response to pressure, heat, stretching, probing with a needle (ahem) and pathological states such as lack of oxygen or tissue damage. In 2009, Burnstock hypothesized that this signaling pathway is essentially how acupuncture works and a series of studies that followed suggests that he’s hit the nail on the head.
In 2010, a mouse study demonstrated that adenosine receptors were required for successful acupuncture pain relief. Mice that were bred without these receptors did not have pain relief from acupuncture whereas their normal counterparts did. 1 A 2012 study demonstrated the same phenomenon, this time in humans, and also showed that the effect was present at an acupuncture point but not at a control point. 2 Another mouse study published just a few months ago strengthens the case even further. The researchers manipulated various aspects of this needle-stimulated pathway and further confirmed that acupuncture’s effects can be completely blocked by blocking purinergic signalling, suggesting that the release of ATP and adenosine in direct physiological response to acupuncture needling may be the first biochemical domino that knocks over the rest. 3
The important point here is not that we now have a definitively correct answer to the question: “How does acupuncture work?” There are many levels on which this question could be answered and different aspects on which we can choose to focus. In my mind, what’s great about purinergic signaling as a central physiological mechanism for acupuncture is that it’s a helpful and plausible answer to this question, on that addresses many criticisms hurled at us by skeptics. As opposed to the vast majority of our body’s signaling pathways, which are highly specialized depending on tissue and body system, ATP and adenosine are ubiquitously present in all tissues and are essentially involved in every process of the body. This can explain why acupuncture is clinically successful in treating so many different symptoms and diseases.
Another leverage point is that the pharmaceutical industry, increasingly aware of the crucial role of purinergic signalling, is in the process of developing drugs to tinker with this system for diseases in every clinical area that you can think of, from neurological, urinary, and gastrointestinal to cancer, pain, autism and immune disorders. 4
The growing support for the central role of purines in acupuncture mechanisms is a wonderful opportunity for us to articulately and confidently explain how our medicine works to a certain type of asker and can give us the tools to be flexible in our communication. For those interested in learning more about how we can increase the public’s access to acupuncture through clearer communication, you can consider attending the Evidence Based Acupuncture symposium in beautiful Providence, Rhode Island, USA taking place 14-15 September 2018. For more information on speakers and topics, check out www.evidencebasedacupuncture.org/symposium.
References
1 Goldman N, Chen M, Fujita T, et al. Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture. Nat Neurosci. 2010;13(7):883-888. doi:10.1038/nn.2562.
2 Takano T, Chen X, Luo F, et al. Traditional Acupuncture Triggers a Local Increase in Adenosine in Human Subjects. The Journal of Pain. 2012;13(12):1215-1223. doi:10.1016/j.jpain.2012.09.012.
3 Huang M, Wang X, Xing B, et al. Critical roles of TRPV2 channels, histamine H1 and adenosine A1 receptors in the initiation of acupoint signals for acupuncture analgesia. Sci Rep. 2018;8(1):6523. doi:10.1038/s41598-018-24654-y.
4 Borea PA, Gessi S, Merighi S, Varani K. Adenosine as a Multi-Signalling Guardian Angel in Human Diseases: When, Where and How Does it Exert its Protective Effects? Trends Pharmacol Sci. 2016;37(6):419-434. doi:10.1016/j.tips.2016.02.006.
