Stimulated by Nakahara et al 2019.
The suggestion of point specific effects always ruffles my metaphorical feathers. I had to come to terms with the use of the term when editing a chapter in the big textbook on medical acupuncture. The chapter was written by the late John Longhurst – an admired cardiologist and physiologist from the US. After a number of comments flew back and forth from London to California, I finally understood what John meant by the term. He was simply referring to the fact that some classically described points stimulated deep somatic nerves and some stimulated cutaneous nerves. It was only stimulation of the former that resulted in any reduction of the hypertensive cardiovascular reflexes his group was studying. I was happy to go along with this explanation, but I still did not like the term.
My use of the term point specificity relates to the idea that certain effects are specific to certain points and only those points – a prevalent myth in the acupuncture world. Here the term myth refers to an unvalidated assertion.
This paper from Japan caught my eye with the term ‘Acupoint dependence…’ in the title, and ‘site specificity’ in the abstract. It is an experimental trial on 60 healthy human subjects that demonstrates some differences in terms of cardiovascular responses to manual acupuncture at different locations. Subjects were randomised to one of 5 groups: a control group that received no acupuncture but just rested and were monitored; and 4 other groups that received manual acupuncture for 2 minutes at either a point in the leg (ST36), a point in the arm (LI10), a point in the abdomen (ST25) or a point in the ear (cavum conchae). A great choice of points I must say!
Unfortunately, the choice of needles and needling was rather too Japanese for my tastes. Obviously, they used great needles (Seirin), but they chose rather thin ones (0.16mm), and only inserted them 5mm. They did mention asking about dull pain or discomfort after the experiment, but did not report on these results, so it is difficult to tell whether or not the muscle level was reached. The needle was moved in and out by 5mm at a frequency of 1Hz, but presumably the tip stayed beneath the epidermis.
The results showed that the heart rate (HR) and blood pressure (BP) remained stable in the control group, and that relative to this, all the acupuncture groups demonstrated a significant drop in HR during stimulation, but only the ST36 group experienced a significant drop in BP.
There are a small number of studies like this in humans, and we are a long way from any consistent results. There is much more research in animal models, but this does not necessarily seem to translate to the same effects in humans.
I am now on my third day with this blog. I have been doing it on the ground and in the air, in clinic, at home and in a conference on the Turkish riviera (WFAS 2019). I have downloaded more than 10 further papers, and I am now calling it a day. I cannot draw any useful conclusion, but only give some vague speculations based on the sage words of past mentors, basic science and its logically extension.
The effect of acupuncture techniques on visceral function are almost entirely indirect. [I am including BP as a visceral function related to autonomic innervation of the peripheral vasculature]. As these effects are indirect, the effect of acupuncture will vary depending on the state of the system at the time of treatment. The farther the system is from a state of homeostatic balance the greater the apparent effect of the acupuncture nudge. If the abnormal state is being maintained by an adverse sensory input (eg visceral pain), acupuncture performed in the ventral segment is likely to have the biggest effect, provided that it is not aversive, in which case it may cause temporary exacerbation of symptoms.
So, the state of the patient, the nature of the condition and the dose and location of treatment may all play a role. This hardly lends itself to the reductionist approach to research that tries to control all variables.
1 Nakahara H, Kawada T, Ueda S-Y, et al. Acupoint dependence of depressor and bradycardic responses elicited by manual acupuncture stimulation in humans. J Physiol Sci Published Online First: 9 November 2019. doi:10.1007/s12576-019-00728-y
2 Longhurst JC. Acupuncture in cardiovascular medicine. In: Filshie J, White A, Cummings M, eds. Medical Acupuncture – A Western Scientific Approach. London: Elsevier 2016. 394–421.
3 Tjen-A-Looi SC, Longhurst CA. John C. Longhurst, MD, PhD (1947-2018): a pioneer in acupuncture hypertension research. Am J Physiol Heart Circ Physiol 2018;314:H1153–4. doi:10.1152/ajpheart.00169.2018
4 Uchida S, Kagitani F, Sato-Suzuki I. Somatoautonomic reflexes in acupuncture therapy: A review. Auton Neurosci Basic Clin 2017;203:1–8. doi:10.1016/j.autneu.2016.11.001