Acupuncture for symptom management of rheumatoid arthritis: a pilot study

Clinical aspects of mastication myalgia-an overview

Mastication myalgia is the most common cause of non-odontogenic pain in the orofacial region and is often associated with a reduced quality of life. The purpose of this review is to provide an overview of the clinical aspects of myalgia based on available research. The review includes epidemiological, diagnostic, and etiological aspects. In addition, the potential risk factors related to the transition from acute to chronic myalgia are explored and treatment strategies are presented for its management. As a result, this review may increase clinical knowledge about mastication myalgia and clarify strategies regarding prevention, diagnostics, and management to improve prognosis and reduce patient suffering.

Effect of electroacupuncture at ST36 on the cerebral metabolic kinetics of rheumatoid arthritis rats

Electroacupuncture (EA) has been shown to enhance the recovery of symptoms in rheumatoid arthritis (RA); however, the underlying mechanism remains unclear. Both the pathogenesis of RA and the therapeutic effects of EA are closely associated with the metabolic activity of the brain. In this study, we investigated the effect of EA at the "Zusanli" acupoint (ST36) on a rat model of collagen-induced rheumatoid arthritis (CIA). The results demonstrated that EA effectively alleviated joint swelling, synovial hyperplasia, cartilage erosion, and bone destruction in CIA rats. Additionally, the metabolic kinetics study revealed a significant increase in the 13C enrichment of GABA2 and Glu4 in the midbrain of CIA rats treated with EA. Correlation network analysis showed that changes in Gln4 levels in the hippocampus were strongly associated with the severity of rheumatoid arthritis. Immunofluorescence staining of c-Fos in the midbrain's periaqueductal gray matter (PAG) and hippocampus demonstrated increased c-Fos expression in these regions following EA treatment. These findings suggest that GABAergic and glutamatergic neurons in the midbrain, along with astrocytes in the hippocampus, may play vital roles in the beneficial effects of EA on RA. Furthermore, the PAG and hippocampus brain regions hold potential as critical targets for future RA treatments. Overall, this study provides valuable insights into the specific mechanism of EA in treating RA by elucidating the perspective of cerebral metabolism.

Electroacupuncture Alleviates Pain Responses and Inflammation in Collagen-Induced Arthritis Rats via Suppressing the TLR2/4-MyD88-NF-κB Signaling Pathway

Results

EA intervention and OxPAPC injection could relieve mechanical allodynia and thermal hyperalgesia caused by CIA. Paw edema and pathological damage of synovium were significantly ameliorated after EA intervention and OxPAPC injection. Furthermore, EA intervention and OxPAPC injection markedly reduced the contents of serum TNF-α, IL-1β, and IL-6, as well as the protein expression levels of synovial TLR2, TLR4, MyD88, and NF-κB p-p65. In particular, the expression of TLR2 and TLR4 on synovial fibroblasts and macrophages in synovium was significantly reduced by EA intervention.

Conclusions

Repeated EA stimulation at ST36 and SP6 can effectively relieve joint pain and synovial inflammation caused by RA in CIA rats. The analgesic and anti-inflammatory effect of EA may be closely related to the inhibition of innate immune responses driven by the TLR2/4-MyD88-NF-κB signaling pathway in the synovium.

Research Hotspots and Trends on Acupuncture for Anti-Inflammation: A Bibliometric Analysis from 2011 to 2021

Purpose

We here explored the research status, research hotspots, and development trend of acupuncture against inflammation from both quantitative and qualitative aspects through bibliometrics.

Methods

We used CiteSpace and VOSviewer to analyze the literature about acupuncture against inflammation from 2011 to 2021 in the Web of Science Core Collection database by using a visual knowledge map.

Results

In total, 1479 articles were included, and the number of articles published each year exhibited an upward trend. The largest number of articles were published in China (661), followed by the United States (287) and South Korea (164). The most productive institution is Beijing University of Chinese Medicine (72), while the most influential institution is the Capital Medical University (0.28). Evidence-based Complementary and Alternative Medicine (131) is the journal that published most articles on the topic. Lin Yiwen is the most prolific author, and Borovikova L is the most influential co-cited author. The keywords that have burst in the last 2 years are inflammation and activation. The keywords with the highest frequency of use are electroacupuncture (EA), inflammation, and expression.

Conclusion

The number of publications on acupuncture for anti-inflammation research is rapidly increasing. China is a productive country, but the influence of centrality is poor. Research institutions are concentrated in universities, and the whole collaborative network needs to be strengthened. The anti-inflammatory mechanism of acupuncture is the main focus of research in this field. Regulation of immune cell balance by acupuncture may be a hot topic in mechanism research. At present, immune cells, vagus nerve, signal pathway, inflammatory corpuscles, cytokines and neurotransmitters are popular research topics. In the future, the basic research of acupuncture for anti-inflammation transformed into clinical practice may be a trend. EA and bee venom acupuncture may be promising research directions for acupuncture treatment for inflammatory diseases.

Are acupuncture and dry needling effective in the management of masticatory muscle pain: A network meta-analysis of randomised clinical trials

BACKGROUND

Several studies have shown that both acupuncture and dry needling are effective in the treatment of musculoskeletal pains. Therefore, the aim of this network meta-analysis (NMA) was to investigate the treatment outcome of acupuncture and dry-needling for masticatory muscle pain (TMD-M) and to compare with active and inactive placebo.

MATERIAL AND METHOD

An electronic search was performed to identify randomised controlled trials (RCTs) published until September 2019, comparing dry-needling, acupuncture, and inactive as well as active placebo in patients with TMD-M. Outcome variables were post-treatment pain intensity, pressure pain threshold (PPT), and maximum mouth opening (MMO). The quality of evidence was rated according to Cochrane's tool for assessing the risk of bias. Mean difference was used to analyse via frequentist NMA using STATA-software.

RESULTS

Both NMA and direct pairwise meta-analysis have shown that there was no difference between active treatment with either acupuncture or dry-needling when compared to active and inactive placebo in patients with TMD-M with respect to pain intensity, and PPT (p > .05). However, there was a significant increase in MMO following dry-needling when compared to the placebo (very low-quality evidence).

CONCLUSION

Despite the short-term positive effect of MMO by dry-needling, this NMA could not show any pain-reducing effect in patients with TMD-M by acupuncture or dry-needling when compared to an active or inactive placebo. Taken together, this NMA indicates that it is the placebo effect that accounts for the majority of the treatment effect of TMD-M, rather than a real therapeutic effect of acupuncture/dry-needling.

Acupuncture for Female Infertility: Discussion on Action Mechanism and Application

A higher incidence of female infertility has been reported with an unexpectedly early appearance in recent years. The female infertility treatment and application of assisted reproductive technology have recently gained immense interest from scientists. Many studies have discussed the beneficial effects of acupuncture on female infertility. With advancements in science and medical technology, acupuncture-related research has increased in investigating its effectiveness in treating female infertility. This review focuses on a compilation of research in recent years on acupuncture for female infertility treatment and the exploration of the underlying mechanism. For this purpose, literature was searched using various search engines like PubMed, Web of Science, and Google Scholar. The search was refined by only focusing on recent studies on acupuncture effectiveness and mechanism in female infertility and evaluating pregnancy outcomes.

Efficacy of Acupuncture and Moxibustion in Alopecia: A Narrative Review

Acupuncture is the practice of applying needles to target specific pressures points in the body. Since originating in China, acupuncture has been practiced for thousands of years to treat numerous conditions including chronic pain and mood disorders. Alopecia is a common dermatologic condition associated with psychological distress and decreased quality of life. Although it remains underexplored in western medicine, recent evidence suggests that acupuncture may be efficacious in the treatment of alopecia. In this review, we discuss the available evidence describing the efficacy of acupuncture or moxibustion alone (ACU) and in combination with other traditional and alternative interventions (ACU + TRAD) for hair loss. Additionally, the proposed physiologic mechanisms, targeted acupuncture points, and the benefits and barriers to treatment will be further described. An exploratory search using PubMed, EMBASE and Scopus databases was performed for studies that evaluated the effect of acupuncture and moxibustion on alopecia. In these studies, both ACU and ACU + TRAD were efficacious for numerous etiologies of hair loss including alopecia areata, androgenetic alopecia, and seborrheic alopecia. Given their ability to modulate the immune system, as well as neuronal networks associated with emotional cognition, the most frequently targeted acupoints were ST 36, GV 20, and LR 3. The proposed mechanistic effect is dependent upon disease etiology and is theorized to be twofold: reduction of inflammation and decrease in testosterone levels. The limited side effect profile of acupuncture makes it an advantageous treatment option, however, factors including cost, time, limited access, and aversion to needles may serve as barriers to treatment.

Potential Mechanisms of Acupuncture for Functional Dyspepsia Based on Pathophysiology

Functional dyspepsia (FD), a common disorder of gastrointestinal function, originated from the gastroduodenum. Although the therapeutic effect of acupuncture has been investigated by various high-quality randomized controlled trials, the potential mechanisms showed obvious heterogeneity. This review summarized the potential mechanisms of acupuncture on FD in order to guide for future laboratory and clinical studies. Here, we argued that the primary cause of FD was gastroduodenal low-grade inflammation and acid exposure, which impaired mucosal integrity, caused brain-gut axis dysfunction, and impaired brain network connectivity, all of which generated various symptom patterns. Overall the clinical studies indicated that acupuncture was a promising treatment to alleviate symptoms in FD patients, whose efficacy was influenced by acupoints and individual variance. Mechanistically, studies with animal models of FD and patients have shown that acupuncture, a non-invasive strategy for nerve stimulation, may have the potential to control intestinal inflammation and suppress acid-secretion via different somatic autonomic reflex pathways, regulate the brain-gut axis through intestinal microbiota, and has the potential to ameliorate FD-symptoms. The cumulative evidence demonstrated that acupuncture is a promising treatment to alleviate symptoms of FD patients.

Needling therapies in the management of myofascial pain of the masticatory muscles: A network meta-analysis of randomised clinical trials

OBJECTIVE

A network meta-analysis (NMA) of randomised clinical trials (RCTs) was performed aiming to compare the treatment outcome of dry needling, acupuncture or wet needling using different substances in managing myofascial pain of the masticatory muscles (TMD-M).

METHOD

An electronic search was undertaken to identify RCTs published until September 2019, comparing dry needling, acupuncture or wet needling using local anaesthesia (LA), botulinum toxin-A (BTX-A), granisetron, platelet-rich plasma (PRP) or passive placebo versus real active placebo in patients with TMD-M. RCTs meeting the inclusion criteria were stratified according to the follow-up time: immediate post-treatment to 3 weeks, and 1 to 6 months post-treatment. Outcome variables were post-treatment pain intensity, increased mouth opening (MMO) and pressure threshold pain (PPT). The quality of evidence was rated according to Cochrane's tool for assessing risk of bias. Mean difference (MD) was used to analysed via frequentist NMA using Stata software.

RESULTS

Twenty-one RCTs involving 959 patients were included. The quality of evidence of the included studies was low or very low. There was significant pain decrease after PRP when compared to an active/passive placebo and acupuncture. There was a significant improvement of MMO after LA (MD = 3.65; CI: 1.18-6.1) and dry needling therapy (MD = 2.37; CI: 0.66-4) versus placebo. The three highest ranked treatments for short-term post-treatment pain reduction in TMD-M (1-20 days) were PRP (95.8%), followed by LA (62.5%) and dry needling (57.1%), whereas the three highest ranked treatments at intermediate-term follow-up (1-6 months) were LA (90.2%), dry needling (66.1%) and BTX-A (52.1%) (all very low-quality evidence). LA (96.4%) was the most effective treatment regarding the increase in MMO followed by dry needling (72.4%).

CONCLUSION

Based on this NMA, one can conclude that the effectiveness of needling therapy did not depend on needling type (dry or wet) or needling substance. The outcome of this NMA suggests that LA, BTX-A, granisetron and PRP hold some promise as injection therapies, but no definite conclusions can be drawn due to the low quality of evidence of the included studies. This NMA did not provide enough support for any of the needling therapies for TMD-M.

Effects of perioperative transcutaneous electrical acupoint stimulation on monocytic HLA-DR expression in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass: study protocol for a double-blind randomized controlled trial

BACKGROUND

Cardiac surgery involving cardiopulmonary bypass (CPB) is known to be associated with a transient postoperative immunosuppression. When severe and persistent, this immune dysfunction predisposes patients to infectious complications, which contributes to a prolonged stay in the intensive care unit (ICU), and even mortality. Effective prevention and treatment methods are still lacking. Recent studies revealed that acupuncture-related techniques, such as electroacupuncture and transcutaneous electrical acupoint stimulation (TEAS), are able to produce effective cardioprotection and immunomodulation in adult and pediatric patients undergoing cardiac surgery with CPB, which leads to enhanced recovery. However, whether perioperative application of TEAS, a non-invasive technique, is able to improve immunosuppression of the patients with post-cardiosurgical conditions is unknown. Thus, as a preliminary study, the main objective is to evaluate the effects of TEAS on the postoperative expression of monocytic human leukocyte antigen (-D related) (mHLA-DR), a standardized "global" biomarker of injury or sepsis-associated immunosuppression, in patients receiving on-pump coronary artery bypass grafting (CABG).

METHODS

This study is a single-center clinical trial. The 88 patients scheduled to receive CABG under CPB will be randomized into two groups: the group receiving TEAS, and the group receiving transcutaneous acupoint pseudo-electric stimulation (Sham TEAS). Expression of mHLA-DR serves as a primary endpoint, and other laboratory parameters (e.g., interleukin [IL]-6, IL-10) and clinical outcomes (e.g., postoperative infectious complications, ICU stay time, and mortality) as the secondary endpoints. In addition, immune indicators, such as high mobility group box 1 protein and regulatory T cells will also be measured.

DISCUSSION

The current study is a preliminary monocentric clinical trial with a non-clinical primary endpoint, expression of mHLA-DR, aiming at determining whether perioperative application of TEAS has a potential to reverse CABG-associated immunosuppression. Although the immediate clinical impact of this study is limited, its results would inform further large-sample clinical trials using relevant patient-centered clinical outcomes as primary endpoints.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02933996. Registered on 13 October 2016.

Acupuncture decreased the risk of coronary heart disease in patients with rheumatoid arthritis in Taiwan: a Nationwide propensity score-matched study

Background

Patients with rheumatoid arthritis (RA) have a higher risk of coronary heart disease (CHD). Acupuncture, a commonly used treatment for patients with RA, has not been reported to prevent CHD in patients with RA. We aimed to assess the risk of developing CHD in acupuncture users and non-users of patients with RA.

Methods

We identified 29,741 patients with newly diagnosed RA from January 1997 to December 2010 from the Registry of Catastrophic Illness Patients Database from the Taiwanese National Health Insurance Research Database. Among them, 10,199 patients received acupuncture (acupuncture users), and 19,542 patients did not receive acupuncture (no-acupuncture users). After performing 1:1 propensity score matching by sex, age, baseline comorbidity, conventional treatment, initial diagnostic year, and index year, there were 9932 patients in both the acupuncture and no-acupuncture cohorts. The main outcome was the diagnosis of CHD in patients with RA in the acupuncture and no-acupuncture cohorts.

Results

Acupuncture users had a lower incidence of CHD than non-users (adjusted HR = 0.60, 95% CI = 0.55–0.65). The estimated cumulative incidence of CHD was significantly lower in the acupuncture cohort (log-rank test, p < .001). Subgroup analysis showed that patients receiving manual acupuncture of traditional Chinese medicine style, electroacupuncture, or combination of both all had a lower incidence of CHD than patients never receiving acupuncture treatment. The beneficial effect of acupuncture on preventing CHD was independent of age, sex, diabetes mellitus, hypertension, hyperlipidemia, and statins use.

Conclusions

This is the first large-scale study to reveal that acupuncture might have beneficial effect on reducing the risk of CHD in patients with RA. This study may provide useful information for clinical utilization and future studies.

Clinical Efficacy of Acupuncture on Rheumatoid Arthritis and Associated Mechanisms: A Systemic Review

OBJECTIVE

The objective of this review is to investigate the detailed existing scientific information about the clinical efficacy of acupuncture on rheumatoid arthritis (RA) conditions and to reveal the proposed mechanisms.

METHODS

We searched the PubMed, EMBASE, Cochrane, AMED (Allied and Complementary Medicine), NCCAM (The National Center for Complementary and Alternative Medicine), and CNKI (China National Knowledge Infrastructure) databases to identify relevant monographs and related references from 1974 to 2018. Chinese journals and theses/dissertations were hand searched.

RESULTS

43 studies were recruited. Each research was analyzed for study design, subject characteristics, intervention, selected acupoints, assessment parameters, proposed mechanisms, and results/conclusions.

CONCLUSIONS

In our review, we concluded that acupuncture alone or combined with other treatment modalities is beneficial to the clinical conditions of RA without adverse effects reported and can improve function and quality of life and is worth trying. Several important possible mechanisms were summarized including anti-inflammatory effect, antioxidative effect, and regulation of immune system function. However, there is still inconsistency regarding the clinical efficacy and lack of well-designed human/animal double-blinded RCTs. Future discussion for further agreement on taking traditional Chinese medicine (TCM) theory into consideration as much as possible is a top priority.

Therapeutic effect of acupuncture in BALB/c model of cutaneous leishmaniasis

Background:

Current research findings demonstrate that acupuncture, a traditional Chinese medicine, has beneficial effects on several acute and chronic infectious and inflammatory diseases. Acupuncture promotes tissue healing and regulates immune response in various disease conditions. Cutaneous leishmaniasis (CL) is a parasitic disease caused by protozoan from genus Leishmania. Acupuncture is supposed to accelerate healing of CL because of common mechanisms involved in the cure of the CL lesions.

Materials and Methods:

60 BALB/c mice were experimentally infected with L. major strain MRHO/IR/75/ER and divided into three groups: (1) Treatment group received acupuncture 2 times a week for 5 weeks (10 sessions) with intraperitoneal diazepam as a sedative agent. (2) Diazepam control group only received diazepam the same as the treatment group. (3) Control group did not receive any intervention. Size of the lesions was measured before the experiment, on session 5 and 10 and 4 weeks after the experiment. Parasite burden was evaluated by microscopic assay as well as quantitative real-time polymerase chain reaction technique.

Results:

Size of the lesions decreased significantly on session 5 in treated group in comparison with session 0 (P = 0.02) while the size of the lesions increased significantly in two control groups on session 5 and 4 weeks after treatment (P = 0.04 and P = 0.01 respectively). Mean parasite burden did not show a significant difference between or within groups on session 0 and 10 by any methods.

Conclusions:

This investigation showed that acupuncture decreased size of the CL lesions by session 5 in the BALB/c mice model, but did not cause a significant reduction in parasite burden.

Electroacupuncture Analgesia Is Improved by Adenoviral Gene Transfer of Dopamine Beta-hydroxylase into the Hypothalamus of Rats

Electroacupuncture (EA) is a modified form of acupuncture that utilizes electrical stimulation. We previously showed that EA stimulated rats were divided into responders that were sensitive to EA and non-responders that were insensitive to EA based on the tail flick latency (TFL) test. The dopamine beta-hydroxylase (DBH) gene was more abundantly expressed in the hypothalamus of responder rats than non-responder rats. To determine whether overexpression of DBH gene expression in the hypothalamus modulate EA analgesia, we constructed a DBH encoding adenovirus and which was then injected into the hypothalamus of SD rats. Microinjection of DBH or control GFP virus into the hypothalamus had no changes on the basal pain threshold measured by a TFL test without EA treatment. However, the analgesic effect of EA was significantly enhanced from seven days after microinjection of the DBH virus, but not after injection of the control GFP virus. DBH expression was significantly higher in the hypothalamus of DBH virus injected rat than control GFP virus or PBS injected rats. Moreover, expression of the DBH gene did not affect the body core temperature, body weight, motor function or learning and memory ability. Although the functional role of DBH in the hypothalamus in the analgesic effect of EA remains unclear, our findings suggest that expression of the DBH gene in the hypothalamus promotes EA analgesia without obvious side-effects.

Acupuncture suppresses kainic acid-induced neuronal death and inflammatory events in mouse hippocampus

The administration of kainic acid (KA) causes seizures and produces neurodegeneration in hippocampal CA3 pyramidal cells. The present study investigated a possible role of acupuncture in reducing hippocampal cell death and inflammatory events, using a mouse model of kainic acid-induced epilepsy. Male C57BL/6 mice received acupuncture treatments at acupoint HT8 or in the tail area bilaterally once a day for 2 days and again immediately after an intraperitoneal injection of KA (30 mg/kg). HT8 is located on the palmar surface of the forelimbs, between the fourth and fifth metacarpal bones. Twenty-four hours after the KA injection, neuronal cell survival, the activations of microglia and astrocytes, and mRNA expression of two proinflammatory cytokines, interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), were measured in the hippocampus. Acupuncture stimulation at HT8, but not in the tail area, significantly reduced the KA-induced seizure, neuron death, microglial and astrocyte activations, and IL-1β mRNA expression in the hippocampus. The acupuncture stimulation also decreased the mRNA expression of TNF-α, but it was not significant. These results indicate that acupuncture at HT8 can inhibit hippocampal cell death and suppress KA-induced inflammatory events, suggesting a possible role for acupuncture in the treatment of epilepsy.

Electroacupuncture Attenuates Ovalbumin-Induced Allergic Asthma via Modulating CD4(+)CD25(+) Regulatory T Cells

A mouse pulmonary hypersensitivity experimental model that mimics human asthma was developed, and electroacupuncture (EA) treatment was shown to reduce allergic inflammatory processes. In addition, we also assessed whether the beneficial effects of EA on allergic asthma could be correlated with CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg). Cellular profiles and histopathologic analysis demonstrated that peribronchial and perivascular inflammatory cell infiltrates were significantly decreased in the EA-treated groups when compared to the OVA and anti-CD25 Ab-injected (Treg depletion) groups. Furthermore, total BAL cells were reduced in the EA groups when compared to other groups. Interestingly, the population of CD4(+)CD25(+)Foxp3(+)Tregs in pneumonocytes increased in EA-treated group when compared to OVA and Treg depletion groups. These results imply that EA stimulation at ST 36 may affect CD4(+)CD25(+)Foxp3(+) Treg in an OVA-induced experimental model and may enhance Treg function by suppressing other T cells and limiting the immune response.

The effects of body acupuncture on obesity: anthropometric parameters, lipid profile, and inflammatory and immunologic markers

A randomized controlled clinical trial in 196 obese subjects was performed to examine the effectiveness of body acupuncture on body weight loss, lipid profile and immunogenic and inflammatory markers. Subjects received authentic (cases) or sham (controls) acupuncture for 6 weeks in combination with a low-calorie diet. In the following 6 weeks, they received the low-calorie diet alone. Subjects were assessed at the beginning, 6 and 12 weeks later. Heat shock protein (Hsps)-27, 60, 65, 70 antibody titers and high sensitivity C-reactive protein (hs-CRP) levels were also assessed. A significant reduction in measures of adiposity and improvement in lipid profile were observed in both groups, but the levels of anti-Hsp-antibodies decreased in cases only. A reduction in anthropometric and lipid profile in cases were sustained in the second period, however, only changes in lipid profile were observed in the control group. Anti-Hsp-antibodies and hs-CRP levels continued to be reduced in cases but in controls only the reduction in hs-CRP remained. Changes in anthropometric parameters, lipid profile, and anti-Hsp-antibodies were more evident in cases. Body acupuncture in combination with diet restriction was effective in enhancing weight loss and improving dyslipidemia.

How should morning function in rheumatoid arthritis be assessed? Bibliographic study of current assessment

In patients with rheumatoid arthritis (RA), symptoms of joint stiffness and pain may be most severe in the morning, resulting in impaired ability to carry out normal morning functions. Although morning stiffness was included in the criteria for classification and remission of RA, defined by the American College of Rheumatology (ACR) in 1987, the approach to assessment of this circadian symptom has not been standardized, and other circadian aspects of the disease (i.e. pain, functional ability) were not included. A bibliographic study of papers published in English in the period January 2007 to January 2010 and reporting morning stiffness, pain or function was undertaken to investigate methods of assessing circadian aspects of RA. A total of 73 studies were identified using Medline, including 62 clinical trials. Full papers were obtained for 52 reports of clinical studies (84%), most of which (44/52, 85%) assessed duration of morning stiffness. Only two studies (4%) specified that severity of morning stiffness was assessed, only three (6%) assessed pain in the morning, and none assessed morning functional ability. These findings suggest the need for consistent reporting of a measure to reflect the impaired morning function, arising from joint stiffness and pain that is commonly experienced by patients.

Possible involvement of histamine, dopamine, and noradrenalin in the periaqueductal gray in electroacupuncture pain relief

Acupuncture and electroacupuncture are used in pain relief; however, the mechanism underlying the analgesic effect of acupuncture is unclear. Several lines of evidence propose that the periaqueductal gray (PAG), which is one of the regions that contributes to the endogenous pain inhibitory system, is involved in the analgesic effect of acupuncture, and the region receives several neural projections such as histamine and noradrenalin and contains the dopamine cell bodies. The current study examined the effects of electroacupuncture at Zusanli (ST36) and Shangjuxu (ST37) acupoints, which are used for clinical pain control, on the release of neurotransmitters in the PAG in rats. Histamine and dopamine release was increased after pain stimulus, while the changes were completely abolished by electroacupuncture. Pain stimulus had no effect on noradrenalin release, but electroacupuncture increased its release. These findings indicate that acupuncture at Zusanli and Shangjuxu exerts an antinociceptive effect via the activation of neurons in the PAG and that the histaminergic, dopaminergic, and noradrenalinergic systems in the PAG are related to electroacupuncture-induced pain relief.