I was alerted to this Longhurst group journal article from last Februay, which I seemed to have missed. It has the advantage of having a free link to the entire article. There is quite a bit of information in there, so enjoy. I discussed the paper before it was published because the author discussed it at the ISAMS conference. I thought the following excerpts were particulary interesting.
In contrast to most pain studies that utilize a VAS to measure pain, Cahn et al. [20] used a survey with yes or no answers to study acupuncture in pain in the pharynx and stomach after gastroscopy. Ninety subjects received either stimulation at 10 verum acupoints, including Chengjiang (CV24), Lianquan (CV23), Shanzhong (CV17), Zhongwan (CV12), Shangqiu (SP5), Neiguan (P6) and two at Zusanli (S36), or sham acupoints 1 cm from the verum acupoints. The researchers found that significantly fewer subjects in the verum acupuncture group experienced pain following treatment compared with the control group. These findings suggest that the inconclusive results in some studies of point specificity in pain could be due to variability in the measurement of outcomes, for example, using a VAS rather than a simpler approach of asking survey questions that have a bidirectional response…
In a comprehensive laboratory study of point specificity, Tjen-A-Looi et al. [18] evaluated changes in reflex increases in blood pressure caused by chemical stimulation of the gallbladder in anesthetized cats during individual stimulation of several sets of acupoints: P5-6, Shousanli-Quchi (LI10-11), LI4-L7, S36-37, LI6-7 and Yongquan-Zhiyin (K1-B67). P5-6, LI4-7, LI10-11 and S36-37 are commonly used to treat cardiovascular disease [18], while LI6-7 and K1-B67 are located along superficial nerves and were used as controls to test the difference between stimulating cutaneous and deep nerves. The investigators found that low-frequency EA stimulation of LI6-7 and K1-B67 did not influence the pressor response, while stimulation of the other sets of acupoints significantly reduced the reflex increases in blood pressure. Furthermore, P5-6 or LI10-11 modulated the response to a significantly greater extent and for a longer duration than LI4-L7 and S36-37. Thus, even though stimulation of many different sets of acupoints may be used to treat cardiovascular disease, their therapeutic effects, with respect to lowering of elevated blood pressure, are distinct in terms of magnitude and duration…
The fMRI data showed that stimulation of S36 and SP6 activated the orbital frontal cortex and deactivated the hippocampus and parietal BA7, regions associated with visceral disorders [45,46]. On the other hand, stimulation of GB34 and B57 increased activity in the dorsal thalamus and inhibited activity in the primary motor and premotor cortices. Interestingly, even though the four acupoints are located within the same spinal segment, they elicited different responses when stimulated. These results suggest that stimulation of different sets of acupoints leads to disease-specific neuronal responses, even when acupoints are located within the same spinal segment…
Moreover, studies have shown that stimulating acupoints along the median and peroneal nerves reduces hypertension by modulating activity in the rostral ventrolateral medulla (rVLM), a center that regulates sympathetic neural outflow. Tjen-A-Looi et al. [18] recorded single-cell neural activity in the rVLM during EA to evaluate point-specific responses of presympathetic neurons to stimulation of P56, LI4-L7, LI6-7, LI10-11, S36-37 and K1-B67 in cats [18]. Activity in the rVLM increased during stimulation of all acupoints but was significantly higher during stimulation of P5-6, located over the median nerve; LI10-11, located over the deep radial nerve and S36-37, situated over the deep peroneal nerve. The duration of the change in rVLM-evoked activity also varied with the acupoint, with P5-6 producing a significantly longer response. The point-specific actions resulting from stimulation of different acupoints in controlled laboratory trials confirm that needling different points on the body produces more than just placebo responses, given that placebo acupuncture is not associated with differential or acupoint-specific responses in anesthetized animals.
