Involvement of endogenous opioid peptides in acupuncture analgesia

Electroacupuncture Reduces Heart Rate and Perceived Exertion During a Bike Test: A Preliminary Analysis

BACKGROUND

Preliminary research suggests that acupuncture can improve cardiovascular function. The purpose of our study was to determine if electroacupuncture can improve performance and post-exercise recovery.

METHODS

Thirty-two healthy people participated in this study (14 men and 18 women, aged 23.6 ± 3.5 years). The first visit included baseline measurements. Then, the participants received daily electroacupuncture at acupuncture point PC6 for a week, followed by a second visit. Heart rate, perceived exertion, and systolic and diastolic blood pressure were measured before, during, and after a YMCA submaximal bike test.

RESULTS

The heart rate was significantly reduced during the final stage of the YMCA test (151.3 ± 7.0 to 146.7 ± 11.8; p = 0.013) on the second visit. The rate of perceived exertion was significantly lower during all stages in Visit 2 (average RPE Visit 2 = 10.71 ± 2.02; average RPE Visit 1 = 11.45 ± 1.98; p = 0.004). Systolic blood pressure significantly decreased during the 5 min post-test recovery (SBP Visit 2 = 116.9 ± 12.0; SBP Visit 1 = 145.7 ± 14.6, p < 0.05).

CONCLUSIONS

A week of electroacupuncture at PC6 led to reduced heart rate and perceived exertion during exercise, making the workload feel less strenuous. Electroacupuncture at PC6 shows potential for increasing participation in physical activities by making them feel easier to accomplish.

Photobiomodulation enhanced endogenous pain modulation in healthy volunteers

To examine the effects of photobiomodulation (PBM) in healthy volunteers using photonic stimulation of acupuncture points on conditioned pain modulation (CPM), temporal summation of pain (TSP), and offset analgesia (OA), which reflect some aspects of endogenous pain modulation. We included 15 men and 15 women (age, 31.5 [27.3-37.0], body mass index, 25.7 [24.4-27.1], Fitzpatrick skin typing, II: 20, III: 8, IV: 2). CPM, TSP, and OA were evaluated after a sham procedure (control session) and after acupuncture point stimulation (LI4 and LI10 on the non-dominant forearm) using linear polarized near-infrared light irradiation (LPNILI; wavelengths peaked at approximately 1000 nm, output: 1.4 W/cm2, spot diameter: 10 mm, spot size: 1.02 cm2, maximum temperature: 40.5 °C, pulse width: 1 s, frequency: 0.2 Hz) (PBM session). Differences in CPM, TSP, and OA between the two sessions were evaluated by the paired t-test and Fisher's exact test (statistical significance: p < 0.05). Values indicate median [interquartile range]. LPNILI significantly increased CPM in all participants (control session: 12.1 [-4.5-37.4], PBM session: 23.9 [8.3-44.8], p < 0.05) and women (control session: 16.7 [-3.4-36.6], PBM session: 38.7 [24.6-52.1], p < 0.05). The CPM effect increment was significantly higher in women than in men (p = 0.0253). LPNILI decreased TSP in participants with higher TSP ratios (p = 0.0219) and increased OA in participants with lower OA scores (p = 0.0021). LPNILI enhanced endogenous pain modulation in healthy volunteers, particularly in women, as evaluated using CPM. CPM, TSP, and OA evaluations are potentially useful for discriminating PBM responders from non-responders.

Contralateral Acupuncture for the Treatment of Phantom Limb Pain and Phantom Limb Sensation in Oncologic Lower Limb Amputee: A Case Report

Phantom limb pain (PLP) and phantom limb sensation (PLS) are common and distressing sequelae of amputation. Current pain management following amputation is challenging and unsatisfying. In this case study, a 74-year-old woman underwent above-knee amputation because of the rhabdomyosarcoma in the right leg. Despite several analgesics, pain was poorly controlled. The phantom limb pain and sensation were immediately reduced by the contralateral acupuncture, and abolished after the third session with no side-effects, no relapse during the next 9 months. Contralateral acupuncture showed positive effect on PLP and PLS in this case, but more robust evidence would be needed to support the efficacy of this treatment technique for indication.

Electroacupuncture versus manual acupuncture for knee osteoarthritis: a randomized controlled pilot trial

OBJECTIVE

We aimed to explore the feasibility of evaluating the comparative effectiveness and safety of electroacupuncture (EA) relative to manual acupuncture (MA) for the treatment of knee osteoarthritis (KOA).

METHODS

A multicenter randomized controlled clinical trial was conducted in Beijing from September 2017 to January 2018. A total of 60 participants with KOA were randomly allocated to either EA (n = 30) or MA (n = 30) groups. Participants in the EA group were treated with EA at six to seven local traditional acupuncture points or ah shi points, and two to three distal points. Participants in the MA group had the same schedule as the EA group except that the electrical apparatus featured a working power indicator without actual current output, constituting a sham EA procedure, in order to blind participants. Both groups received 24 sessions over 8 weeks. The primary outcome was response rate, defined as a change of ⩾50% from baseline in the total scores of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) after 8 weeks. Secondary outcomes included pain, stiffness, function, quality of life, and acupuncture-related adverse events (AEs) at 4 and 8 weeks.

RESULTS

Of 60 participants randomized, 53 (88%) completed the study. Response rates were 43% for the EA group and 30% for the MA group by the intention-to-treat analysis. Although significant differences were observed in WOMAC pain, stiffness, and function scores within both groups, between-group differences at 8 weeks did not reach statistical significance (odds ratio = 1.75 (95% confidence interval = 0.593-5.162)). Rates of AEs were low and similarly distributed between groups.

CONCLUSION

Both EA and MA interventions in KOA were feasible and appeared safe. Whether or not EA may have a stronger impact on pain and function requires further evaluation through larger, adequately powered, randomized controlled trials.

TRIAL REGISTRATION NUMBER

NCT03274713.

Ipsi- and Contralateral Moxibustion Generate Similar Analgesic Effect on Inflammatory Pain

The aim of this study was to investigate whether contralateral moxibustion would generate a similar analgesic effect with ipsilateral moxibustion. Contra- and ipsilateral moxibustion were separately applied to Zusanli (ST36) acupoints of inflammatory pain mice. The analgesic effect was evaluated, respectively, by licking/biting time (LBT) of formalin-induced inflammatory pain and thermal withdrawal latency (TWL) of complete Freund's adjuvant- (CFA-) induced inflammatory pain. For formalin-induced pain, compared with formalin group, the total LBT of ipsi- and contralateral moxibustion reduced in both phase I and phase II, but there was no significant difference between ipsi- and contralateral moxibustion. For CFA-induced inflammatory pain, compared with CFA group, TWL of ipsi- and contra-Moxi groups increased immediately after moxibustion intervention; however there was no obvious difference between ipsi- and contralateral moxibustion at any timepoint. It indicated that contralateral moxibustion had a similar analgesic effect with ipsilateral moxibustion in both formalin- and CFA-induced pain. These results suggest that both ipsi- and contralateral moxibustion could be applied for pain relief.

Increased Plasma β-Endorphin Concentrations after Acupuncture: Comparison of Electroacupuncture, Traditional Chinese Acupuncture, Tens and Placebo Tens

Seventeen patients with pain from various causes were treated by Electroacupuncture (n=5), Traditional Chinese Acupuncture (n=4), Transcutaneous Electrical Nerve Stimulation (n=4) or Placebo TENS (n=4). Each treatment lasted 25 minutes. Plasma β-endorphin concentrations were measured before and after the session. Electroacupuncture and Traditional acupuncture treatments were both associated with a significant rise in plasma β-endorphin levels.

Suppression of Experimental Pain by Auriculopressure

In a controlled trial at a University Clinic of Physical Therapy and Rehabilitation, healthy student volunteers were given auriculopressure to investigate its analgesic effect. There were two study groups, each containing 30 volunteers. The first group was given auriculopressure to the toe somatic point on the ear, with pressure sensitivity being measured on the skin of the toe with an algometer device before and after ear stimulation. The control group had the same measurements with placebo stimulation to the ear. In the auriculopressure group the increase in pain threshold was statistically significant. In the placebo control group there was no significant change. These results suggest that auriculopressure could be a useful method for suppression of post-traumatic somatic pain.

Pain in Mucopolysaccharidoses: Analysis of the Problem and Possible Treatments

Mucopolysaccharidosis (MPS) are a group of lysosomal storage disorders that are caused by the deficiency of enzymes involving in the catabolism of glycosaminoglycan (GAGs). GAGs incompletely degraded accumulate in many sites, damaging tissues and cells, leading to a variety of clinical manifestations. Many of these manifestations are painful, but few data are available in the literature concerning the prevalence, etiology, and pathogenesis of pain in children with MPS. This review, through the analysis of the data available the in literature, underscores the relevant prevalence of pain in MPSs’ children, provides the instruments to discern the etiopathogenesis of the disease and of pain, illustrates the available molecules for the management of pain and the possible advantages of non-pharmacological pain therapy in MPSs’ patients.

Efficacy of Acupuncture in the Management of Primary Dysmenorrhea: A Randomized Controlled Trial

INTRODUCTION

Dysmenorrhea constitutes one of the most frequent disorders in women of a fertile age. The present study was conducted to evaluate the efficacy of acupuncture in the management of primary dysmenorrhea.

MATERIALS AND METHODS

Sixty females aged 17-23 years were randomly assigned to either a study group or a control group. The study group received acupuncture for the duration of 20 minutes/day, for 15 days/month, for the period of 90 days. The control group did not receive acupuncture for the same period. Baseline, during, and post assessments of both the groups were taken on day 1; day 30 and day 60; and day 90, respectively. Statistical analysis was performed by repeated measures of analysis of variance followed by post hoc analysis with Bonferroni adjustment for multiple comparisons, independent samples t test for visual analog scale score, and Mann-Whitney U test for rest of the variables using statistical package for the social sciences, version 16.

RESULTS

This study showed a significant reduction in all the variables such as the visual analog scale score for pain, menstrual cramps, headache, dizziness, diarrhea, faint, mood changes, tiredness, nausea, and vomiting in the study group compared with those in the control group.

CONCLUSION

Acupuncture could be considered as an effective treatment modality for the management of primary dysmenorrhea.

Prophylactic treatment with the tricyclic antidepressant desipramine prevents development of paclitaxel-induced neuropathic pain through activation of endogenous analgesic systems

Neuropathic pain impacts approximately 3-4.5% of the global population and remains an unresolved health problem. The management of neuropathic pain has two distinct goals-prevention of development and control of established neuropathic pain. We examined the impact of both prophylactic and therapeutic treatments with the tricyclic antidepressant desipramine on the development and maintenance of toxic neuropathic pain induced by the chemotherapeutic agent paclitaxel. We also investigated the involvement of endogenous analgesic (i.e., endogenous opioid and endocannabinoid) systems in the antinociceptive actions of desipramine in these two distinct phases of neuropathic pain. Chronic subcutaneous infusion of desipramine via osmotic pumps suppressed both the development and maintenance of paclitaxel-induced neuropathic pain. However, only prophylactic desipramine treatment blocked the development of neuropathic pain throughout the three month observation interval; neuropathic pain did not return. The opioid receptor antagonist naloxone blocked the antinociceptive effects of both prophylactic and therapeutic desipramine treatments throughout the entire timecourse of desipramine-induced antinociception. By contrast, cannabinoid CB₁ and CB₂ receptor antagonists partially attenuated the antinociceptive actions of desipramine in a manner that was restricted to the development phase of paclitaxel-induced neuropathic pain only. Paclitaxel decreased cell viability in TMD231 tumor cells in an MTT assay in vitro. Notably, desipramine (1nM-1μM) alone did not alter tumor cell viability and did not prevent the cytotoxic effects of paclitaxel under identical conditions. The highest concentration of desipramine (10μM) reduced tumor cell viability alone and enhanced the cytotoxic effects of paclitaxel. Our study identifies a previously unrecognized preemptive analgesic strategy that prevents development of paclitaxel-induced neuropathic pain, and also dissects receptor mechanisms underlying desipramine-induced antinociceptive effects. This information may be applied to improve current therapeutic strategies with the goal of preventing and managing neuropathic pain induced by chemotherapeutic treatment.

Acupuncture assisted local anesthesia for penile surgeries

Although the mechanism of acupuncture for analgesia is not fully elucidated, a combination of acupuncture and several methods of topical blocks for local anesthesia has been effective to patients with indications for penile surgeries on ambulatory basis. We sought to review this unique clinical application since 1998. To summarize practice-based medical literature contingent this unique application and, in contrast, the commonly agreed either general or spinal anesthesia concerning those surgeries on this most sensitive organ—the delicate penis. From July 1998 to July 2013, total of 1,481 males underwent penile surgeries with specific topical nerve blockage in addition to acupuncture in which the acupoints of Hegu (LI4), Shou San Li (LI10), Quchi (LI11), and either Waiguan (TE5) or Neiguan (PC6) were routinely used. Careful anesthetic block of the paired dorsal nerve in the penile hilum associated with a peripenile infiltration was categorized to method I which is sufficient to anesthetize the penile structures for varied penile surgeries including 993 men of penile venous stripping surgeries, 336 cases of penile corporoplasty, 8 males of urethroplasty, 7 patients of vaso-vasostomy, 6 men of penile arterial reconstruction and 3 surgeries of penectomy. Whereas the bilateral cavernous nerve block and crural blockage were indispensably added up for anesthetizing the sinusoids of the corpora cavernosa (CC) for penile implant of varied model. It was allocated to method II and had been applied in 125 males. A further topical injection of the medial low abdominal region made it possible for implanting a three-piece model in three males. Thus recent discoveries and better understanding of the penile anatomy had been meaningful in the development and improvement of specific nerve blockade techniques for penile surgeries in particularly adding up with acupuncture techniques, while minimizing anesthetic adverse effects and resulting in a rapid return to daily activity with minimal complications.

Nonpharmacological interventions for pain management in paramedicine and the emergency setting: a review of the literature

Paramedicine and the emergency medical services have been moving in the direction of advancing pharmaceutical intervention for the management of pain in both acute and chronic situations. This coincides with other areas of advanced life support and patient management strategies that have been well researched and continue to benefit from the increasing evidence. Even though paramedic practice is firmly focused on pharmacological interventions to alleviate pain, there is emerging evidence proposing a range of nonpharmacological options that can have an important role in pain management. This review highlights literature that suggests that paramedicine and emergency medical services should be considering the application of complementary and alternative therapies which can enhance current practice and reduce the use of pharmacological interventions.

Acupuncture Alleviated the Nonmotor Symptoms of Parkinson's Disease including Pain, Depression, and Autonomic Symptoms

A woman started to feel intractable pain on her lower legs when she was 76. At the age of 78, she was diagnosed as having Parkinson's disease (PD). The leg pain was suspected to be a symptom of PD after eliminating other causes. The patient also suffered from nonmotor symptoms, depression, anxiety, hot flashes, and paroxysmal sweating. Though the patient had received pharmacotherapy including levodopa for 5 years, she still suffered from the nonmotor symptoms and was referred to our department. We treated her with acupuncture based on the Chinese traditional medicine and electroacupuncture five times per week. After the 2-week treatment, the assessment for the symptoms was as follows; visual analogue scale (VAS) score of the leg pain was 16 mm (70 mm, before), Hamilton's rating scales for depression (HAM-D) score was 9 (18, before), timed 3 m Up and Go took 20 steps in 30 sec (24 steps in 38 sec, before), and the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part 1 score was 13 (21, before). Autonomic symptoms, hot flashes and paroxysmal sweating, were also alleviated. Acupuncture may be a good treatment modality for nonmotor symptoms in PD.

Successful practice of electroacupuncture analgesia in equine surgery

Electroacupuncture analgesia was used for surgery in horses and donkeys. A KWD-808 electrical stimulator was used to incrementally induce a dense, dispersed wave output at frequencies from 20 to 55 Hz, which was maintained at a frequency of 55 Hz, and to change the amplitude of the wave to the best grading number for the suggested operation in each animal. Induction of analgesia lasted for 20-30 minutes, and the effect of analgesia was maintained for 20-45 minutes depending on the type of surgery performed. The exhibited clinical signs, physical examination data, and the responses of all animals were used for evaluating the periods of analgesia. Although the majority of the cases (95%) had no response to strong surgical pain, they experienced significant increases in heart rates and respiratory rates during induction. The lack of pain, relaxed surgical procedures, reduced intraoperative bleeding, and improved healing without complications were all definite benefits of using electroacupuncture analgesia in surgery. Thus, this study has provided surgical evidence supporting the effectiveness of electroacupuncture analgesia, as well as confirming its reliability, in the field of equine anesthesia and surgery.

An exploratory review of the electroacupuncture literature: clinical applications and endorphin mechanisms

Electroacupuncture (EA) is widely used in clinical practice and research, as well as in experimental investigations into the mechanisms of acupuncture. This study explores publication trends in clinical and experimental studies of EA (1975-2011) for pain and non-pain research; EA use for different clinical conditions (1974-2012); and the relation of EA research, including stimulation frequency, to opioid peptide mechanisms. Appropriate PubMed 'all fields' searches were conducted, identified studies were classified using PubMed filters and manually, and data extracted into tables. A total of 2916 clinical studies were located, of which 19% involved EA. Additionally, 3344 animal studies were located, of which 48% involved EA. The publication rate of EA studies per year has risen over time, but the percentage of studies of pain has fallen from 60% to 25%. The conditions most commonly treated with EA are musculoskeletal, neurological, obstetric and gastrointestinal, along with intraoperative and postoperative analgesia. EA studies, particularly with low frequency stimulation, are more likely to support the role of endogenous opioid mechanisms than manual acupuncture studies, and opioid release is more likely in the central nervous system than the circulation. EA is increasingly used in clinical and especially experimental research, particularly for non-pain conditions. Acupuncture does release endogenous opioids, but this probably depends on 'dosage', with the evidence more consistent and convincing for EA than for manual acupuncture. Different frequencies of EA appear to activate different endogenous opioid mechanisms.

The Relationship between Traditional Chinese Medicine and Modern Medicine

The essence of the traditional Chinese medicine has always been the most advanced and experienced therapeutic approach in the world. It has knowledge that can impact the direction of future modern medical development; still, it is easy to find simple knowledge with mark of times and special cultures. The basic structure of traditional Chinese medicine is composed of three parts: one consistent with modern medicine, one involuntarily beyond modern medicine, and one that needs to be further evaluated. The part that is consistent with modern medicine includes consensus on several theories and concepts of traditional Chinese medicine, and usage of several treatments and prescriptions of traditional Chinese medicine including commonly used Chinese herbs. The part that is involuntarily beyond modern medicine contains several advanced theories and important concepts of traditional Chinese medicine, relatively advanced treatments, formula and modern prescriptions, leading herbs, acupuncture treatment and acupuncture anesthesia of traditional Chinese medicine that affect modern medicine and incorporates massage treatment that has been gradually acknowledged by modern therapy. The part that needs to be further evaluated consists not only the knowledge of pulse diagnosis, prescription, and herbs, but also many other aspects of traditional Chinese medicine.

Understanding central mechanisms of acupuncture analgesia using dynamic quantitative sensory testing: a review

We discuss the emerging translational tools for the study of acupuncture analgesia with a focus on psychophysical methods. The gap between animal mechanistic studies and human clinical trials of acupuncture analgesia calls for effective translational tools that bridge neurophysiological data with meaningful clinical outcomes. Temporal summation (TS) and conditioned pain modulation (CPM) are two promising tools yet to be widely utilized. These psychophysical measures capture the state of the ascending facilitation and the descending inhibition of nociceptive transmission, respectively. We review the basic concepts and current methodologies underlying these measures in clinical pain research, and illustrate their application to research on acupuncture analgesia. Finally, we highlight the strengths and limitations of these research methods and make recommendations on future directions. The appropriate addition of TS and CPM to our current research armamentarium will facilitate our efforts to elucidate the central analgesic mechanisms of acupuncture in clinical populations.

Auricular acupuncture for chemically dependent pregnant women: a randomized controlled trial of the NADA protocol

Background

The prevalence of maternal drug use during pregnancy in North America has been estimated to be as high as 6-10%. The consequences for the newborn include increased risk for perinatal mortality and ongoing physical, neurobehavioral, and psychosocial problems. Methadone is frequently used to wean women off street drugs but is implicated as a cause of adverse fetal/neonatal outcomes itself. The purpose of our study was to test the ability of maternal acupuncture treatment among mothers who use illicit drugs to reduce the frequency and severity of withdrawal symptoms among their newborns.

Methods

We randomly assigned chemically dependent pregnant women at BC Women’s Hospital in Vancouver, British Columbia to daily acupuncture treatments versus usual care. By necessity, neither our participants nor acupuncturists were blinded as to treatment allocation. Our primary outcome was days of neonatal morphine treatment for symptoms of neonatal withdrawal. Secondary neonatal outcomes included admission to a neonatal ICU and transfer to foster care.

Results

We randomized 50 women to acupuncture and 39 to standard care. When analyzed by randomized groups, we did not find benefit of acupuncture; the average length of treatment with morphine for newborns in the acupuncture group was 2.7 (6.3) compared to 2.8 (7.0) in the control group. Among newborns of women who were compliant with the acupuncture regime, we observed a reduction of 2.1 and 1.5 days in length of treatment for neonatal abstinence syndrome compared to the non-compliant and control groups, respectively. These differences were not statistically significant.

Conclusions

Acupuncture may be a safe and feasible treatment to assist mothers to reduce their dosage of methadone. Our results should encourage ongoing studies to test the ability of acupuncture to mitigate the severity of neonatal abstinence syndrome among their newborns.

Clinical Trial Registration

http://www.clinicaltrials.gov registry: W05-0041

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.

Analgesic mechanism of electroacupuncture in an arthritic pain model of rats: a neurotransmitter study

PURPOSE

We investigated what kinds of neurotransmitters are related with electroacupuncture (EA) analgesia in an arthritic pain model of rats.

MATERIALS AND METHODS

One hundred rats were assigned to six groups: control, EA, opioid, adrenergic, serotonin and dopamine group. A standardized model of inflammatory arthritis was produced by injecting 2% carrageenan into the knee joint cavity. EA was applied to an acupoint for 30 min in all groups except fo the control group. In the opioid, adrenergic, serotonin and dopamine groups, each receptor antagonist was injected intraperitoneally to their respective group before initiating EA.

RESULTS

In the opioid receptor antagonist group, adrenergic receptor antagonist group, serotonin receptor antagonist group, dopamine receptor antagonist group and the control group weight-bearing force decreased significantly from 30 min to 180 min after EA in comparison with the EA group.

CONCLUSION

The analgesic effects of EA are related to opioid, adrenergic, serotonin and dopamine receptors in an arthritic pain model of rats.

Rostral ventromedial medulla μ, but not κ, opioid receptors are involved in electroacupuncture anti-hyperalgesia in an inflammatory pain rat model

It has been reported that intracerebroventricular injection of a μ receptor antagonist blocked 2 but not 100Hz electroacupuncture (EA)-produced analgesia in an uninjured animal model. Because persistent pain changes neural response to external stimulation, we hypothesized that the mechanisms of EA anti-hyperalgesia may be different in persistent pain than in health. Hyperalgesia, decreased paw withdrawal latency (PWL) to a noxious thermal stimulus, was induced by subcutaneously injecting complete Freund's adjuvant (CFA) into the hind paws of rats. Selective antagonists against μ (CTOP: D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-ThrNH2, 6.25 nmol) and κ (Nor-BIN: nor-binaltorphimine, 10 nmol) opioid receptors were infused into the rostral ventromedial medulla (RVM) 10 min before a 30-min EA treatment at acupoint Huantiao (GB30) 1h 30 min post-CFA. PWL was measured before and 2.5 post-CFA. Both 10 Hz and 100 Hz EA-produced anti-hyperalgesia were blocked by intra-RVM μ, but not κ, receptor antagonists. Double immunofluorescence staining demonstrated that μ receptor-containing neurons were GABAnergic and that GABAa receptor-containing neurons were serotonergic in the RVM. The results demonstrated an involvement of RVM μ, but not κ, receptors in EA-produced anti-hyperalgesia. In summary, EA may induce release of endogenous endomorphins that activate μ opioid receptors in GABAnergic neurons to suppress the release of GABA. This removes the tonic inhibition of GABA on serotonergic neurons in the RVM, and activation of these serotonergic neurons inhibits pain. EA may be used as complementary treatment for inflammatory pain.

Involvement of peripheral opioid receptors in electroacupuncture analgesia for carrageenan-induced hyperalgesia

Acupuncture is widely used to relieve pain; however, the mechanism underlying electroacupuncture analgesia (EAA) during inflammatory pain is unclear. We investigated whether endogenous peripheral opioid receptors participated in EAA during hyperalgesia elicited by carrageenan-induced inflammation. Moreover, we investigated which subtype of opioid receptor was involved in EAA. Carrageenan was subcutaneously administered by intraplanter (i.pl.) injection into the left hind paw. Nociceptive thresholds were measured using the paw pressure threshold (PPT). Rats received 3Hz electroacupuncture (EA) for 1h after carrageenan injection. The nonselective peripheral opioid receptor antagonist, naloxone methiodide, was administered by i.pl. injection of the inflamed paw 5min before EA. Also, animals received i.pl. or intravenous (i.v.) injection of selective antagonists against μ(D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-ThrNH2, CTOP), δ(naltrindole, NTI), or κ (nor-Binaltorphimine, nor-BNI) opioid receptors 1h before EA. PPT decreased significantly 3h after carrageenan injection. EA resulted in significant increases of PPT, moreover, PPT elevations persisted for 9h after carrageenan injection. PPT elevations produced by EA were antagonized by local i.pl. injection of naloxone methiodide at 3 and 5h after cessation of EA. NTI, nor-BNI and CTOP blocked EAA from immediately, 1h, and 3h after EA cessation, respectively. The EAA in the inflamed paw could not be blocked by i.v. injection of NTI, nor-BNI and CTOP. These findings suggest that peripheral μ, δ and κ receptors on peripheral nerve terminals are activated by EA, although there is a time difference among these activations.

Brain manifestation and modulation of pain from myofascial trigger points

The brain plays a prominent role in the generation and modulation of pain. It contains powerful endogenous pain modulatory systems that can be engaged in a beneficial way by therapeutical intervention. In contrast, pain chronification is associated with maladaptive structural and functional changes that may shift the balance of the modulatory systems. Although pain from myofascial trigger points (MTrPs) is highly prevalent, little is known about its brain manifestations and modulation. Recent neuroimaging data suggest that hyperalgesia from MTrPs is processed in similar regions as hyperalgesia from other pain conditions. However, abnormal hippocampal hypoactivity suggests that dysfunctional stress responses may play an important role in the generation and maintenance of hyperalgesia from MTrPs. Other data suggest that short-term pain relief obtained with intramuscular electrostimulation within an MTrP is partially due to descending pain inhibitory mechanisms.

The genome-wide expression profile of electroacupuncture in DNP-KLH immunized mice

Previously, we demonstrated that electoracupuncture (EA) suppressed allergic reactions in DNP-KLH immunized mice. In this study, the mechanisms by which EA induces immunomodulation in the immunized mice were evaluated by genome-wide microarray analysis. The anti-allergic effects of EA in DNP-KLH immunized mice were confirmed by analyzing antigen specific IgE using ELISA. Microarray analysis, followed by real time RT-PCR validation, revealed that Th1 and Th17 cytokine-, opioid peptide-, and anti-apoptosis-related genes were up-regulated upon treatment with EA. In addition, significant decreases in Th2 cytokine-, MAPK signaling pathway-, and apoptosis-related genes were observed following EA treatment.

DNIC-mediated analgesia produced by a supramaximal electrical or a high-dose formalin conditioning stimulus: roles of opioid and alpha2-adrenergic receptors

Background

Diffuse noxious inhibitory controls (DNIC) can be produced by different types of conditioning stimuli, but the analgesic properties and underlying mechanisms remain unclear. The aim of this study was to differentiate the induction of DNIC analgesia between noxious electrical and inflammatory conditioning stimuli.

Methods

First, rats subjected to either a supramaximal electrical stimulation or an injection of high-dose formalin in the hind limb were identified to have pain responses with behavioral evidence and spinal Fos-immunoreactive profiles. Second, suppression of tail-flick latencies by the two noxious stimuli was assessed to confirm the presence of DNIC. Third, an opioid receptor antagonist (naloxone) and an α2-adrenoreceptor antagonist (yohimbine) were injected, intraperitoneally and intrathecally respectively, before conditioning noxious stimuli to test the involvement of descending inhibitory pathways in DNIC-mediated analgesia.

Results

An intramuscular injection of 100 μl of 5% formalin produced noxious behaviors with cumulative pain scores similar to those of 50 μl of 2% formalin in the paw. Both electrical and chemical stimulation significantly increased Fos expression in the superficial dorsal horns, but possessed characteristic distribution patterns individually. Both conditioning stimuli prolonged the tail-flick latencies indicating a DNIC response. However, the electrical stimulation-induced DNIC was reversed by yohimbine, but not by naloxone; whereas noxious formalin-induced analgesia was both naloxone- and yohimbine-reversible.

Conclusions

It is demonstrated that DNIC produced by different types of conditioning stimuli can be mediated by different descending inhibitory controls, indicating the organization within the central nervous circuit is complex and possibly exhibits particular clinical manifestations.

Neural mechanism underlying acupuncture analgesia

Acupuncture has been accepted to effectively treat chronic pain by inserting needles into the specific "acupuncture points" (acupoints) on the patient's body. During the last decades, our understanding of how the brain processes acupuncture analgesia has undergone considerable development. Acupuncture analgesia is manifested only when the intricate feeling (soreness, numbness, heaviness and distension) of acupuncture in patients occurs following acupuncture manipulation. Manual acupuncture (MA) is the insertion of an acupuncture needle into acupoint followed by the twisting of the needle up and down by hand. In MA, all types of afferent fibers (Abeta, Adelta and C) are activated. In electrical acupuncture (EA), a stimulating current via the inserted needle is delivered to acupoints. Electrical current intense enough to excite Abeta- and part of Adelta-fibers can induce an analgesic effect. Acupuncture signals ascend mainly through the spinal ventrolateral funiculus to the brain. Many brain nuclei composing a complicated network are involved in processing acupuncture analgesia, including the nucleus raphe magnus (NRM), periaqueductal grey (PAG), locus coeruleus, arcuate nucleus (Arc), preoptic area, nucleus submedius, habenular nucleus, accumbens nucleus, caudate nucleus, septal area, amygdale, etc. Acupuncture analgesia is essentially a manifestation of integrative processes at different levels in the CNS between afferent impulses from pain regions and impulses from acupoints. In the last decade, profound studies on neural mechanisms underlying acupuncture analgesia predominately focus on cellular and molecular substrate and functional brain imaging and have developed rapidly. Diverse signal molecules contribute to mediating acupuncture analgesia, such as opioid peptides (mu-, delta- and kappa-receptors), glutamate (NMDA and AMPA/KA receptors), 5-hydroxytryptamine, and cholecystokinin octapeptide. Among these, the opioid peptides and their receptors in Arc-PAG-NRM-spinal dorsal horn pathway play a pivotal role in mediating acupuncture analgesia. The release of opioid peptides evoked by electroacupuncture is frequency-dependent. EA at 2 and 100Hz produces release of enkephalin and dynorphin in the spinal cord, respectively. CCK-8 antagonizes acupuncture analgesia. The individual differences of acupuncture analgesia are associated with inherited genetic factors and the density of CCK receptors. The brain regions associated with acupuncture analgesia identified in animal experiments were confirmed and further explored in the human brain by means of functional imaging. EA analgesia is likely associated with its counter-regulation to spinal glial activation. PTX-sesntive Gi/o protein- and MAP kinase-mediated signal pathways as well as the downstream events NF-kappaB, c-fos and c-jun play important roles in EA analgesia.

Effect of varying frequency and duration of electroacupuncture stimulation on carrageenan-induced hyperalgesia

OBJECTIVE

Although electroacupuncture (EA) therapy is used to relieve various kinds of pain, the optimal frequency and duration of EA remain unclear. We investigated the effect of varying frequency and duration of EA during hyperalgesia elicited by carrageenan-induced inflammation.

METHODS

Carrageenan was administered by subcutaneous intraplantar injection to induce inflammation. Nociceptive thresholds were measured using the paw pressure threshold (PPT) (Randall-Selitto Test). EA was applied at 3, 15, or 100Hz to the left anterior tibial muscles for 1, 15, or 60 minutes. Intensities used were chosen within the known tolerance of the animal, and increased up to 3mA for 3Hz, and up to 1.5mA for 15 and 100Hz. EA was started three hours after carrageenan injection.

RESULTS

Three hours after carrageenan injection, a marked ipsilateral inflammatory response appeared and PPT decreased significantly. This decrease persisted for at least 24 hours after carrageenan injection. EA at 3Hz (60 minutes) resulted in significant increases of PPT which persisted for 24 hours after injection. EA at 3Hz (15 minutes) also induced PPT elevations immediately and for one hour after EA compared to the control group. However, no other variety of EA significantly increased PPT.

CONCLUSION

These results show that EA produces electroacupuncture analgesia of carrageenan-induced hyperalgesia. These findings also suggest that, among the frequencies and durations tested, EA at 3Hz (60 minutes) is the most suitable frequency and duration for carrageenan-induced inflammation. It seems that EA has different analgesic effects and mechanisms according to the parameters of stimulation. For EA in the clinical induction of analgesia, it is especially important that an effective frequency and duration are selected.

Electroacupuncture analgesia in dogs: is there a difference between uni- and bi-lateral stimulation?

OBJECTIVE

To compare the analgesic effect of uni- and bi-lateral electroacupuncture (EA) in response to thermal and mechanical nociceptive stimuli and to investigate the cardiorespiratory, endocrine, and behavioral changes in dogs submitted to EA.

STUDY DESIGN

Prospective, randomized cross-over experimental study.

ANIMALS

Eight adult, clinically healthy, cross-breed dogs, weighing 13 +/- 4 kg.

METHODS

Dogs underwent electrostimulation at false acupoints (T-false); bilateral EA at acupoints, stomach 36, gall bladder 34 and spleen 6 (T-EA/bil); unilateral EA at the same points (T-EA/uni) or were untreated (T-control). All animals received acepromazine (0.05 mg kg(-1)) IV; and heart rate, pulse oximetry, indirect arterial blood pressure, respiratory rate, Pe'CO(2), rectal temperature, and plasma cortisol concentration were measured before, during, and after EA. Analgesia was tested using thoracic and abdominal cutaneous thermal and mechanical stimuli, and an interdigital thermal stimulus. Behavior was classified as calm or restless. Analysis of variance for repeated measures followed by Tukey's test was used for analysis of the data.

RESULTS

There were no cardiorespiratory differences among the treatments. The cutaneous pain threshold was higher after EA, compared with false points. The latency period was shorter and analgesia was more intense in T-EA/bil than T-EA/uni, when both were compared with T-false and T-control. Six out of eight animals treated with EA were calm during treatment, and 5/8 and 4/8 of the T-false and T-control animals, respectively, were restless. Latency to interdigital thermal stimulation increased in T-EA/bil compared with the others. There was no difference in plasma cortisol concentrations among the treatments.

CONCLUSIONS

Bilateral EA produced a shorter latency period, a greater intensity, and longer duration of analgesia than unilateral stimulation, without stimulating a stress response.

CLINICAL RELEVANCE

Bilateral EA produces a better analgesic effect than unilateral EA.

The acute effect of acupuncture on 20-km cycling performance

OBJECTIVE

To examine acupuncture's effect on cycling performance.

DESIGN

This was a prospective, single-blind, patient as own control (repeated measures), crossover design. Subjects underwent 3 tests a week, riding a stationary bike for 20-km as fast as able. Before each test, they received acupuncture (test A), "sham" acupuncture (test B), and no intervention (control, test C) once each in a random order.

SETTING

University of Alberta, Faculty of Rehabilitation Medicine.

PARTICIPANTS

20 male cyclists (age, 18 to 30 years) were recruited via convenience sampling of students and general public. Athletic ability was assessed through a questionnaire and modified Par-Q.

INTERVENTIONS

Acupuncture, sham acupuncture, and no intervention in random order with each subject before each test. Acupuncture points were chosen on the basis of Traditional Chinese Medicine and administered immediately before cycling. Sham was shallow needling of known acupoints.

MAIN OUTCOME MEASUREMENTS

The outcome measures of each of the tests were time to completion, VAS for lower extremity/exercise-induced pain, Borg rating of perceived exertion (RPE), and blood lactate concentrations, recorded immediately following each test.

RESULTS

Mean times to Test A, B, and C completion were 36.19 +/- 5.23, 37.03 +/- 5.66, and 37.48 +/- 6.00 minutes, respectively, P = 0.76. Mean RPE scores after tests A, B, and C were 17.65 +/- 0.67, 16.95 +/- 0.99, and 16.85 +/- 0.88, respectively, P = 0.0088. Mean VAS scores after tests A, B, and C were 7.72 +/- 0.86, 7.94 +/- 0.78, and 8.08 +/- 0.69, respectively, P = 0.76.

CONCLUSIONS

The only statistically significant finding was that acupuncture gave higher RPE scores compared to the other tests. The clinical significance was that the higher RPE scores gave lower time and VAS scores.

Non-pharmacological techniques for pain management in neonates

Significant progress in understanding the physiology, clinical correlates, and consequences of neonatal pain have resulted in greater attention to pain management during neonatal intensive care. A number of nonpharmacological therapies have been investigated, including nonnutritive sucking, with and without sucrose use, swaddling or facilitated tucking, kangaroo care, music therapy, and multi-sensorial stimulation. Although the efficacy of these approaches is clearly evident, they cannot provide analgesia for moderate or severe pain in the neonate. Further, some of these therapies cannot be effectively applied to all populations of critically ill neonates. Acupuncture, an ancient practice in Chinese medicine, has gained increasing popularity for symptom control among adults and older children. Acupuncture may provide an effective nonpharmacological approach for the treatment of pain in neonates, even moderate or severe pain, and should be considered for inclusion in a graduated multidisciplinary algorithm for neonatal pain management.

Central Modulation of Pain Evoked From Myofascial Trigger Point

OBJECTIVES

Low-intensity low-frequency electrostimulation delivered within a myofascial trigger point (MTP) has been used as intervention to deactivate MTPs. The therapeutic effect has been suggested to be due to peripheral mechanisms. However, nonpainful stimuli are also known to reduce simultaneous pain through central effects. The primary objective of the present study was to assess if central pain modulation occurs after intervention with low-intensity electrostimulation within an MTP. We hypothesized that intervention induces pain inhibition via the periaqueductal gray (PAG).

METHODS

Twenty-four patients with myofascial pain syndrome participated in the study. During functional magnetic resonance scanning, painful (high-intensity) intramuscular electrostimulation was delivered at random intervals (mean interstimulus interval=10.2 s) within an MTP of the upper left trapezius muscle. In-between scanning sessions, intervention (intramuscular electrostimulation, low-intensity, interstimulus interval=0.5 s) was applied to the same area. Patients were divided into responders and nonresponders according to their change in pressure pain thresholds relative to intervention. In addition to a whole brain search, a region of interest approach was also implemented to test the effect of intervention on PAG signal change.

RESULTS

The main findings were: (1) intervention modulated PAG activity to painful stimuli more in responders than in nonresponders, (2) change in PAG activity from the whole patient population correlated with change in pressure pain threshold, and (3) a network known to regulate affective qualities of the pain experience was (subsignificantly) engaged more in responders than in nonresponders.

DISCUSSION

The applied intervention most likely involves supraspinal pain control mechanisms related to both antinociception and regulation of pain affect.

Electroacupuncture-induced analgesia in a rat model of ankle sprain pain is mediated by spinal alpha-adrenoceptors

In a previous study, we showed that electroacupuncture (EA) applied to the SI-6 point on the contralateral forelimb produces long-lasting and powerful analgesia in pain caused by ankle sprain in a rat model. To investigate the underlying mechanism of EA analgesia, the present study tested the effects of various antagonists on known endogenous analgesic systems in this model. Ankle sprain was induced in anesthetized rats by overextending their right ankle with repeated forceful plantar flexion and inversion of the foot. When rats developed pain behaviors (a reduction in weight-bearing of the affected hind limb), EA was applied to the SI-6 point on the contralateral forelimb for 30 min under halothane anesthesia. EA significantly improved the weight-bearing capacity of the affected hind limb for 2h, suggesting an analgesic effect. The alpha-adrenoceptor antagonist phentolamine (2mg/kg, i.p. or 30 microg, i.t.) completely blocked the EA-induced analgesia, whereas naloxone (1mg/kg, i.p.) failed to block the effect. These results suggest that EA-induced analgesia is mediated by alpha-adrenoceptor mechanisms. Further experiments showed that intrathecal administration of yohimbine, an alpha(2)-adrenergic antagonist, reduced the EA-induced analgesia in a dose-dependent manner, whereas terazosin, an alpha(1)-adrenergic antagonist, did not produce any effect. These data suggest that the analgesic effect of EA in ankle sprain pain is, at least in part, mediated by spinal alpha(2)-adrenoceptor mechanisms.

Effects of traditional “Juci” (contralateral acupuncture) on orofacial nociceptive behavior in the rat

PURPOSE

"Juci", one of the traditional acupuncture techniques, means contralateral acupuncture; i.e., implanting a needle into an acupoint to treat a given disease or disorder, but on the side of the body opposite to the diseased side. The aim of this study was: (1) to assess acupuncture effects on formalin-induced nociceptive behavior in the orofacial region in the rat, and (2) to evaluate the efficacy of Juci in the orofacial formalin test.

METHODS

Forty-four adult male Wistar rats were used in the present study. A 1.0% formalin solution (25 microl s.c., diluted in saline) was injected into the right upper lip. The rats were randomly assigned to five groups. (1) The control group (n = 9), which received formalin injection without acupuncture pretreatment; (2) the ipsilateral Ho-ku (see note below) acupuncture group (n = 10); (3) the contralateral Ho-ku acupuncture group (n = 11); (4) the acupuncture plus naloxone group (n = 9), where intraperitoneal naloxone (1.0 mgxkg(-1)) was injected immediately before acupuncture pretreatment; and (5) the sham acupuncture group (n = 5). "Ho-ku" is the term used for the "Large Intestine 4" acupoint, located between the first and second metacarpal bones.

RESULTS

The injection of formalin produced the characteristic biphasic behavioral response. Acupuncture significantly inhibited the response in the early and late phases. Naloxone significantly reversed these effects. There were no statistically significant differences between the ipsilateral and Juci acupuncture groups. Sham acupuncture did not exert any significant effect on the formalin-induced behavior.

CONCLUSION

Our results showed that the degree of effectiveness of Juci was similar to that of the ipsilateral acupuncture technique. Therefore, the Juci technique is also useful for the treatment of orofacial pain.

Pain-relieving effects of acupuncture and electroacupuncture in an animal model of arthritic pain

The effects of acupuncture and electroacupuncture on an animal model of arthritic pain were examined. Under halothane anesthesia, arthritic pain was induced by the injection of carrageenan into the knee joint cavity of male Sprague-Dawley rats. Behavioral performance was tested before and after the termination of acupuncture or electroacupuncture. Electrophysiologically, the responses of afferents to a movement cycle were recorded before and after acupuncture or electroacupuncture. After the acupuncture procedure, the weight-bearing force of the rats was significantly improved and the neural responses to noxious movement stimulation were reduced. Electroacupuncture significantly improved weight-bearing behavior and inhibited neural responses of articular afferents to noxious stimulation. These results indicate that acupuncture and electroacupuncture may provide a potent strategy in relieving arthritic pain.

Mu opioid receptor-containing neurons mediate electroacupuncture-produced anti-hyperalgesia in rats with hind paw inflammation

Previous studies showed that electroacupuncture (EA) significantly attenuates inflammatory hyperalgesia in a complete Freund's adjuvant (CFA)-induced inflammatory pain rat model. The present study demonstrates that pretreatment with Derm-sap, a selective toxin for neurons that contain mu opioid receptor (MOR), specifically decreases MOR and blocks EA anti-hyperalgesia. These data suggest that spinal MOR-containing neurons are involved in the processes by which EA produces anti-hyperalgesia.

Electroacupuncture reduces rectal distension-induced blood pressure changes in conscious dogs

It has been shown that acupuncture relieves symptoms of abdominal pain and bloating in patients with irritable bowel syndrome (IBS). However, the mechanism of beneficial effects of acupuncture still remains unproven. The aim of the present study was to investigate the mechanisms of the antinociceptive effects of acupuncture in conscious dogs. We evaluated the increase in mean arterial blood pressure (MAP) caused by rectal distension as an index of visceral pain. Electroacupuncture (EA; 10 Hz) at ST-36 (lower leg), but not at BL-21 (back), significantly reduced the increase in MAP in response to rectal distension (30 and 40 cm3). The antinociceptive effect of EA at ST-36 was abolished by pretreatment with naloxone (a central and peripheral opioid receptor antagonist) but not by naloxone methiodide (a peripheral opioid receptor antagonist). These results suggest that EA at ST-36 may reduce visceral pain via central opioid pathway. Acupuncture may be useful to treat visceral hypersensitivity in IBS patients.

Effects of acupuncture at GV01 on experimentally induced colitis in rats: possible involvement of the opioid system

Oriental medicine uses acupuncture at the GV01 acupoint with great success to treat diarrhea. It significantly reduced the colonic motility and inflammation in colitic rats. Naloxone pretreatment blocked these effects. The therapeutic effects of acupuncture at GV01 in colitis may involve endogenous opioid pathways.

Activation of Spinal Anti-analgesic System Following Electroacupuncture Stimulation in Rats

We evaluated the interaction between electroacupuncture (EA)-induced antinociception and an endogenous anti-analgesic system. EA was applied to the ST-36 acupoint for 45 min in male Sprague-Dawley rats, and pain thresholds were assessed by the hind-paw pressure test. EA produced a marked increase in pain thresholds and its antinociceptive action was completely reversed by naloxone (5 mg/kg). The analgesic effects of subcutaneous morphine (7 mg/kg) following EA stimulation were significantly attenuated. The attenuation of morphine analgesia was inversely proportional to the time intervals between EA termination and morphine injection, and the effect was not observed 120 min after EA stimulation. The analgesic effects of i.t. morphine (10 microg), but not i.c.v. morphine (25 microg), following EA were also attenuated. On the other hand, systemic morphine (7 mg/kg)-induced hyperthermia was not affected by EA. Moreover, i.c.v. morphine, but not i.t. morphine, produced hyperthermia. The i.c.v. morphine-induced hyperthermia was not affected by EA, similar to i.c.v. morphine analgesia. These results suggest that the attenuation of morphine analgesia following EA, that is, the activation of an endogenous anti-analgesic system, is closely related to the activation of an analgesic system by EA and that the spinal cord plays a critical role in the activation of the endogenous anti-analgesic systems.

Acupuncture has a placebo effect on rectal perception but not on distensibility and spatial summation: a study in health and IBS

BACKGROUND

Recent data suggest that acupuncture has effects on gut physiology and perception. Spatial summation is a central mechanism of perception and describes the phenomenon that thresholds for perception are lower if more receptors are stimulated.

OBJECTIVES

We assessed perception thresholds for rectal distension and cutaneous referral of symptoms, while inflating one or two rectal balloons and the effect of both electro-acupuncture and placebo-acupuncture on rectal distensibility, perception, and spatial summation.

METHODS

A tube with two barostat balloons was placed in the rectum of 12 healthy subjects and nine irritable bowel syndrome (IBS) patients with rectal symptoms. Volume-controlled stepwise distension of the distal balloon only or both balloons was performed first as a control, and thereafter with simultaneous placebo- or electro-acupuncture in dermatomes S3 and S4. A symptom questionnaire and anatomic questionnaire was completed during each distension.

RESULTS

Rectal elastance increased from 42.0 +/- 19.6 log mmHg/ml during one-balloon distension to 59.6 +/- 33.1 log mmHg/ml during two-balloon distension (p < 0.05) in healthy subjects, and from 48.8 +/- 14.4 log mmHg/ml (one balloon) to 77.6 +/- 24.2 log mmHg/ml (p < 0.001) in patients with IBS. Electro-acupuncture had no effect on rectal sensation, elastance, and cutaneous referral when compared to placebo-acupuncture. However, acupuncture (both electro- and placebo-) increased volume thresholds for sensation compared to control experiments, while objective parameters like rectal tone and elastance were unaltered.

CONCLUSION

Acupuncture has a placebo effect on rectal perception but has no effect on rectal distensibility and visceral referral. Spatial summation affected both rectum distensibility and perception, but was also not altered by acupuncture.

Multiple sources of endogenous opioid peptide involved in the hypoglycemic response to 15 Hz electroacupuncture at the Zhongwan acupoint in rats

A decrease in plasma glucose levels was observed in rats which received electroacupuncture (EA) stimulation at the Zhongwan acupoint. In the present study, the role of the adrenal gland in this hypoglycemic response to EA at high frequency (15 Hz) was investigated on adrenalectomized (ADX) normal rats. There was a sharper decrease in plasma glucose by EA stimulation in the fasting ADX group than in the fasting sham-operated group. Naloxone blocked this hypoglycemic response to EA stimulation in rats which received ADX. Stimulation of EA failed to elicit an increase in plasma beta-endorphin and insulin levels in ADX rats. Similar results were observed in sham and ADX mice. EA stimulation of ADX mice can reduce plasma glucose levels. Furthermore, naloxone abolished the hypoglycemic response to EA stimulation in mice. Such a hypoglycemic response to EA stimulation was also observed in micro-opioid receptor knockout mice (MOR-KOM). Mediation by another opioid peptide should also be considered in future experiments. We conclude that multiple sources of endogenous opioid peptide participated in the lowering of plasma glucose in rats induced by EA stimulation at higher frequency (15 Hz) at the Zhongwan acupoint. Increase in beta-endorphin levels from the adrenal gland enhances the secretion of insulin, there by reducing plasma glucose levels, and is partially involved in this EA stimulation.