Mechanisms of Acupuncture–Electroacupuncture on Persistent Pain

Abstract

In the last decade, preclinical investigations of electroacupuncture mechanisms on persistent tissue-injury (inflammatory), nerve-injury (neuropathic), cancer, and visceral pain have increased. These studies show that electroacupuncture activates the nervous system differently in health than in pain conditions, alleviates both sensory and affective inflammatory pain, and inhibits inflammatory and neuropathic pain more effectively at 2–10 Hz than at 100 Hz. Electroacupuncture blocks pain by activating a variety of bioactive chemicals through peripheral, spinal, and supraspinal mechanisms. These include opioids, which desensitize peripheral nociceptors and reduce pro-inflammatory cytokines peripherally and in the spinal cord, and serotonin and norepinephrine, which decrease spinal n-methyl-d-aspartate receptor subunit GluN1 phosphorylation. Additional studies suggest that electroacupuncture, when combined with low dosages of conventional analgesics, provides effective pain management that can forestall the side effects of often-debilitating pharmaceuticals.

Peripheral and Spinal Mechanisms of Pain and Dry Needling Mediated Analgesia: A Clinical Resource Guide for Health Care Professionals

“…Ahsin et al reported a significant increase in plasma β-endorphin levels after EDN to local points at the knee that correlated with reductions in pain, stiffness and disability, which is likely due to vasodilation [144]. EDN further blocks the local release of IL-1 β and TNF-α in the synovia of osteoarthritic joints [145] and the systemic release of IL-1 β and TNF-α by inhibiting melanocortin-4 in the periaqueductal gray of the brain stem [146]. Third, there is limited evidence suggesting that DN may stimulate an increase in hyaluronic acid, allowing the synovial fluid to better lubricate the joint [147].…”

“…Importantly, CRH has also been shown to directly stimulate opioids release from immune cells, and CRH antagonists have been shown to block EDN's ability to inhibit pain in inflammatory tissue [156]. Corticosterone locally inhibits inflammatory cytokines, prostaglandin and cox-2, thereby optimizing opioid-based pain reduction [146,151,154]. The CRH-POMCcorticosteroid axis provides another mechanism by which EDN may be able to have an effect peripherally via non-neural cells and may further explain the positive effects of superficial DN.…”

Acupuncture as adjuvant general anesthesia on cesarean section

“…Electroacupuncture stimulates Aβ fibers and modulates Nucleus Rafe Magnus (NRM) to produce analgesia. Acupuncture exerts an effect through central and peripheral mechanisms evidenced by both experimental of human and animal studies and also involves various bioactive chemicals or mediators as shown in Figure 4 [13,14].…”

Complementary and alternative medicine therapies for the anesthesiologist and pain practitioner: a narrative review

“…13 Acupuncture combined with non-narcotic analgesics may obviate the need for opioid therapy and reduce side effects associated with higher dosages of medication. 14 Assertions in recently performed literature reviews suggest that acupuncture may be effective for peripheral joint osteoarthritis, neck pain, tension-type headaches, migraine prophylaxis, and labour pain ( Table 2). For example, in 2011, Lee and Ernst published an analysis of Cochrane reviews that thoroughly addresses the specific evidence on acupuncture for pain.…”

“…73 Despite controversy over a lack of adequate blinding and potential intellectual biases against acupuncture and other complementary therapies, evidence exists to support these therapies even at the mechanistic level. 14,[74][75][76] For example, several animal models have shown a therapeutic effect for acupuncture and other CAM therapies. Furthermore, since animals likely do not understand the difference between true vs sham therapies, we can infer that they are not likely to exhibit a placebo response.…”