Biological mechanisms of acupuncture

Recent advances in acupuncture for pain relief

Introduction

Acupuncture therapy has achieved global expansion and shown promise for health promotion and treatment of acute/chronic pain.

Objectives

To present an update on the existing evidence base for research and clinical practice supporting acupuncture analgesia.

Methods

This Clinical Update elaborates on the 2023 International Association for the Study of Pain Global Year for Integrative Pain Care "Factsheet Acupuncture for Pain Relief" and reviews best evidence and practice.

Results

Acupuncture is supported by a large research evidence base and growing utilization. Mechanisms of acupuncture analgesia include local physiological response at the needling site, suppression of nociceptive signaling at spinal and supraspinal levels, and peripheral/central release of endogenous opioids and other biochemical mediators. Acupuncture also produces pain relief by modulating specific brain networks, integral for sensory, affective, and cognitive processing, as demonstrated by neuroimaging research. Importantly, acupuncture does not just manage pain symptoms but may target the sources that drive pain, such as inflammation, partially by modulating autonomic pathways. Contextual factors are important for acupuncture analgesia, which is a complex multifaceted intervention. In clinical practice, historical records and many providers believe that acupuncture efficacy depends on specific acupoints used, the technique of needle placement and stimulation, and the person who delivers the procedure. Clinical research has supported the safety and effectiveness of acupuncture for various pain disorders, including acupuncture as a complementary/integrative therapy with other pain interventions.

Conclusion

Although the quality of supportive evidence is heterogeneous, acupuncture's potential cost-effectiveness and low risk profile under standardized techniques suggest consideration as a neuromodulatory and practical nonpharmacological pain therapy.

Brainstem Pain-Modulation Circuitry and Its Plasticity in Neuropathic Pain: Insights From Human Brain Imaging Investigations

Acute pain serves as a protective mechanism that alerts us to potential tissue damage and drives a behavioural response that removes us from danger. The neural circuitry critical for mounting this behavioural response is situated within the brainstem and is also crucial for producing analgesic and hyperalgesic responses. In particular, the periaqueductal grey, rostral ventromedial medulla, locus coeruleus and subnucleus reticularis dorsalis are important structures that directly or indirectly modulate nociceptive transmission at the primary nociceptive synapse. Substantial evidence from experimental animal studies suggests that plasticity within this system contributes to the initiation and/or maintenance of chronic neuropathic pain, and may even predispose individuals to developing chronic pain. Indeed, overwhelming evidence indicates that plasticity within this circuitry favours pro-nociception at the primary synapse in neuropathic pain conditions, a process that ultimately contributes to a hyperalgesic state. Although experimental animal investigations have been crucial in our understanding of the anatomy and function of the brainstem pain-modulation circuitry, it is vital to understand this system in acute and chronic pain states in humans so that more effective treatments can be developed. Recent functional MRI studies have identified a key role of this system during various analgesic and hyperalgesic responses including placebo analgesia, offset analgesia, attentional analgesia, conditioned pain modulation, central sensitisation and temporal summation. Moreover, recent MRI investigations have begun to explore brainstem pain-modulation circuitry plasticity in chronic neuropathic pain conditions and have identified altered grey matter volumes and functioning throughout the circuitry. Considering the findings from animal investigations, it is likely that these changes reflect a shift towards pro-nociception that ultimately contributes to the maintenance of neuropathic pain. The purpose of this review is to provide an overview of the human brain imaging investigations that have improved our understanding of the pain-modulation system in acute pain states and in neuropathic conditions. Our interpretation of the findings from these studies is often guided by the existing body of experimental animal literature, in addition to evidence from psychophysical investigations. Overall, understanding the plasticity of this system in human neuropathic pain conditions alongside the existing experimental animal literature will ultimately improve treatment options.

Transcutaneous electrical nerve stimulation, acupuncture, and spinal cord stimulation on neuropathic, inflammatory and, non-inflammatory pain in rat models

Background

Transcutaneous electrical nerve stimulation (TENS), manual acupuncture (MA), and spinal cord stimulation (SCS) are used to treat a variety of pain conditions. These non-pharmacological treatments are often thought to work through similar mechanisms, and thus should have similar effects for different types of pain. However, it is unclear if each of these treatments work equally well on each type of pain condition. The purpose of this study was to compared the effects of TENS, MA, and SCS on neuropathic, inflammatory, and non-inflammatory pain models.

Methods

TENS 60 Hz, 200 μs, 90% motor threshold (MT), SCS was applied at 60 Hz, an intensity of 90% MT, and a 0.25 ms pulse width. MA was performed by inserting a stainless-steel needle to a depth of about 4-5 mm at the Sanyinjiao (SP6) and Zusanli (ST36) acupoints on a spared nerve injury (SNI), knee joint inflammation (3% carrageenan), and non-inflammatory muscle pain (intramuscular pH 4.0 injections) in rats. Mechanical withdrawal thresholds of the paw, muscle, and/or joint were assessed before and after induction of the pain model, and daily before and after treatment.

Results

The reduced withdrawal thresholds were significantly reversed by application of either TENS or SCS (P < 0.05). MA, on the other hand, increased the withdrawal threshold in animals with SNI and joint inflammation, but not chronic muscle pain.

Conclusions

TENS and SCS produce similar effects in neuropathic, inflammatory and non-inflammatory muscle pain models while MA is only effective in inflammatory and neuropathic pain models.

Implementation of Electrical Auricular Acupuncture and Low Frequency Modulated Electric Current Therapy in Pain Management of Patients with Knee Osteoarthritis: A Randomized Pilot Trial

Background: Knee osteoarthritis is a major cause of knee pain. Conservative therapy resources are limited due to adverse effects. Therefore, alternative non-invasive therapy approaches to reduce pain medications are gaining importance. The current study analyses if electrical auricular acupuncture (EAA) or low frequency modulated electric current therapy (LFMECT) could support analgesic treatment. Methods: In a randomized pilot trial patients with painful knee OA were treated with EAA (group 1) or LFMECT (group 2) additional to standard pharmacological analgesic treatment. In total 19 female and 10 male patients with a mean age of 59.1 years (standard deviation ± 13.6) and a mean BMI of 28.9 kg/m² (± 5.2) were included. Patients were randomly assigned to one of the groups stratified for age, gender and BMI. Before starting of the active study period and collecting of the initial data on day 1, all patients received a pharmacological analgesic baseline therapy for one week. At the next study stage patients started their randomly assigned treatment protocol for 42 days and final follow-up was set on day 70. Patients recorded their pain intensity (numerical rating scale; NRS) using a standardized patient diary. The pain free walking time in min was recorded and range of motion was assessed. Results: Rescue medication intake was comparable between both groups on day 42 (p = 0.55) and day 70 (p = 0.35). After the active study period (day 42) pain scores decreased significantly in both groups (group 1 p = 0.02; group 2 p = 0.0006). At follow up median pain scores further decreased in group 1 (p = 0.0002) and remained at a low level in group 2 (p = 0.001). Level of pain decreased in about 50% in both groups and was comparable during the study period. Total mean range of motion (ROM) increased in both groups (group 1 p = 0.0003; group 2 p = 0.02). Group 1 had more improvement of mean total ROM compared to group 2 (p = 0.034). Pain-free walking time increased in both groups and was comparable between both groups (p = 0.31). Any adverse effects due to EAA or LFMECT were not observed. Conclusions: Data of the current study indicates that implementation of EAA or LFMECT seems to be beneficial to reduce knee pain and improve knee function in patients with knee osteoarthritis.

Role of Auriculotherapy in the Treatment of Temporomandibular Disorders with Anxiety in University Students

Introduction. The aim of this study was to evaluate the role of auriculotherapy with mustard seeds in the treatment of temporomandibular disorders (TMDs), anxiety, and electromyographic (EMG) activity in university students. Methodology. The State Trait Anxiety Inventory (STAI), Research Diagnostic Criteria (RDC) for TMDs (RDC/TMDs), and electromyography were used in this study of 44 college students with high levels of anxiety and TMDs. The subjects were divided into two groups: an auriculotherapy (AA) group (n = 31) and an AA sham group (n = 13). The mustard seeds were applied to the shenmen, rim, sympathetic, brain stem, and temporomandibular joint (TMJ) points in the AA group and to sham points in the external ear and wrist in the AA sham group. The treatment protocol was 10 sessions (two treatments per week). Results. Anxiety (p < 0.01) was significantly reduced in the AA group. This group also showed a decrease in tender points in the mandibular posterior region (p = 0.04) and in the right side of the submandibular region (p = 0.02). Complaints of bilateral pain were reduced in the temporal tendon (p ≤ 0.01) and in the left side of the ATM (p < 0.01). In addition, electromyographic (EMG) activity was reduced during temporal muscle contraction (p = 0.03).  Conclusion. Auriculotherapy was effective in the treatment of students with anxiety and TMDs.

Acupuncture at KI3 in healthy volunteers induces specific cortical functional activity: an fMRI study

Background

Using functional magnetic resonance imaging (fMRI), we determined brain regions that were activated/deactivated more by acupuncture at Taixi (KI3) than by non-acupoint or sham acupuncture.

Methods

A total of 30 healthy volunteers were randomly divided into a KI3 group (15 subjects) and non-acupoint group (15 subjects). Subjects in KI3 group received a sham acupuncture and then a real acupuncture, fMRI was performed before and after sham acupuncture as well as after ture acupuncture. Subjects in non-acupoint group received a ture acupuncture and the fMRI was performed before and after ture acupuncture. The fMRI data obtained were successively analyzed using DPARSF2.3 and REST1.8 software, yielding regional homogeneity (ReHo) and amplitude of low frequency fluctuations (ALFF) values.

Results

Compared with sham acupuncture, ALFF values were higher in Brodmann area (BA) 10 and lower in BA7 and BA18. ReHo values after real acupuncture at KI3 were higher in the right sub-lobar region and BA10 and were lower in BA31. Compared with the changes before and after real acupuncture at non-acupoint, the changes at KI3 showed higher ALFF valued in the left cerebellum posterior lobe, BA10, BA39, BA31 and decreased ALFF was observed in the BA18, BA19 and BA40; and higher ReHo values were shown in left cerebellum posterior lobe pyramis, left cerebellum anterior lobe. BA37, BA10, BA39, BA31 and lower ReHo values were shown in BA18 and BA31.

Conclusion

Acupuncture at KI3 has a specific effect on certain brain regions associated with perception, body movement, spirit, and association. Additionally, visual and auditory cortices were affected, which may be related to the clinical applications of KI3 acupuncture in auditory and cognitive disorders, hypomnesis, loss of concentration, and the loss of ability to work and learn.

Trial registration

The research ethics committee was achieved at 01/08/2012, the NO. was ChiECRCT-2012011. Website for Clinical Trial Registration: http://www.chictr.org.cn/showproj.aspx?proj=7123.

This study was registered at www.chictr.org, the Clinical Trial Registration Number was ChiCTR-TRC-12002427, and the registration number was achieved at 18/08/2012. The name of IRB that provided approval for the study and clearly state is Chinese Clinical Trail Registry.

The effect of low-concentration atropine combined with auricular acupoint stimulation in myopia control

OBJECTIVES

To compare the effect of myopia control between patients treated with low-concentration atropine eye drops combined with auricular acupoint stimulation and those treated with atropine alone.

DESIGN AND SETTINGS

Single-blinded randomized controlled clinical trial in a regional teaching hospital.

INTERVENTIONS

The patients received either topical 0.125% atropine nightly plus auricular acupoint stimulation (0.125A + ACU group) or topical 0.125% atropine alone nightly (0.125A group).

MAIN OUTCOME MEASURES

The changes in spherical equivalent (SE), axial length (AL), anterior chamber depth (ACD), and intraocular pressure (IOP) per year were compared between the two groups.

RESULTS

Seventy-three of 110 total patients (66.4%) completed at least 6 months of follow-up. Patients in the 0.125A + ACU group had less myopic progression and AL elongation (-0.41 diopter and 0.24 mm/year) than those in the 0.125A group (-0.66 diopter and 0.32 mm/year) (mean follow-up 14.7 months, p < 0.0001 and p = 0.02, respectively). The ACD increased more in the 0.125A + ACU group than in the 0.125A group (0.076 mm vs. 0.023 mm/year, p = 0.0004). IOP decreased more in the 0.125A + ACU group than in the 0.125A group (-1.01 mmHg vs. -0.13 mmHg/year, p = 0.007). A decrease of 1 mmHg of IOP correlated with a decrease of myopic progression of 0.021 diopter/year (p = 0.006).

CONCLUSIONS

Patients treated with 0.125% atropine eye drops plus auricular acupoint stimulation had less myopic progression, less axial length elongation, more anterior chamber deepening, and greater IOP reductions than those treated with 0.125% atropine alone. Auricular acupoint stimulation in combination with low-concentration topical atropine was beneficial for myopia control.

Cerebral blood flow-based evidence for mechanisms of low- versus high-frequency transcutaneous electric acupoint stimulation analgesia: a perfusion fMRI study in humans

Brain activities in response to acupuncture have been investigated in multiple studies; however, the neuromechanisms of low- and high-frequency transcutaneous electric acupoint stimulation (TEAS) analgesia are unclear. This work aimed to investigate how brain activity and the analgesic effect changed across 30-min low- versus high-frequency TEAS. Forty-six subjects received a 30-min 2, 100-Hz TEAS or mock TEAS (MTEAS) treatment on both behavior test and functional magnetic resonance imaging (fMRI) scan days. On the behavior test day, the pain thresholds and pain-related negative emotional feeling ratings were tested five times - at 4.5min before treatment, at 10, 20, and 30min during treatment and 4.5min after the treatment. On the fMRI scan day, to match the time-points in the behavioral testing session, the cerebral blood flow (CBF) signals were collected and incorporated with five independent runs before, during and after the treatment, each lasting 4.5min. The analgesic effect was observed in both the TEAS groups; the analgesic affect was not found in the MTEAS group. The effect started at 20min during the treatment and was maintained until the after-treatment states. In both TEAS groups, the regional CBF revealed a trend of early activation with later inhibition; also, a positive correlation between analgesia and the regional CBF change was observed in the anterior insula in the early stage, whereas a negative relationship was found in the parahippocampal gyrus in the later stage. The TEAS analgesia was specifically associated with the default mode network and other cortical regions in the 2-Hz TEAS group, ventral striatum and dorsal anterior cingulate cortex in the 100-Hz TEAS group, respectively. These findings suggest that the mechanisms of low- and high-frequency TEAS analgesia are distinct and partially overlapped, and they verify the treatment time as a notable factor for acupuncture studies.

Mechanisms of acupuncture-electroacupuncture on persistent pain

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 to 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 proinflammatory 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 which can forestall the side effects of often-debilitating pharmaceuticals.

Neuroanatomical basis for acupuncture point PC8 in the rat: neural tracing study with cholera toxin subunit B

OBJECTIVES

This study was performed to investigate the innervations related to acupuncture point PC8 in rats using a neural tracing technique.

METHODS

After 6 μL of 1% cholera toxin subunit B (CTB) was injected into the site between the second and third metacarpal bone in rats, a corresponding site to acupuncture point PC8 in the human body, CTB labelling was examined with immunofluorescence and immunohistochemistry in the dorsal root ganglia (DRG), spinal cord and brainstem.

RESULTS

All CTB labelling appeared on the ipsilateral side of the injection. The labelled sensory neurons distributed from cervical (C)6 to thoracic (T)1 DRG, while the labelled motor neurons were located on the dorsolateral part of the spinal ventral horn ranging from the C6 to T1 segments. In addition, the transganglionically-labelled axonal terminals were found to be dense in the medial part of laminae 3-4 from C6 to the T1 spinal dorsal horn, as far as in the cuneate nucleus.

CONCLUSIONS

These results indicate that sensory and motor neurons associated with PC8 distribute in a distinct segmental pattern. The sensory information from PC8 could be transganglionically transported to the spinal dorsal horn and cuneate nucleus.

The meridian system and mechanism of acupuncture-a comparative review. Part 1: the meridian system

In traditional Chinese medicine (TCM), acupuncture has been used to heal various diseases and physiologic malfunctions in clinical practice for more than 2500 years. Due to its efficacy, acupuncture has been recommended by the World Health Organization in 1980 as an effective alternative therapy for 43 different disorders. Over the past few decades, various theories of the meridian system and mechanisms have been proposed to explain how acupuncture might work. Most of these mechanisms, however, cannot yet explain conclusively why acupuncture is efficacious in treating so many different diseases. A plausible mechanism has been unavailable until recently. This is the first of a three-part series that aims to provide a comparative review of the aforementioned topics. Part 1 reviews the current indications for acupuncture, basic concepts of TCM, and the essence of the meridian system. To establish a mathematically rigorous framework of TCM, the chaotic wave theory of fractal continuum is proposed. This theory is then applied to characterize the essence of the meridian system. Parts 2 and 3 will review the possible mechanisms of acupuncture analgesia and acupuncture therapies, respectively, based on biochemical, bioelectromagnetic, chaotic wave, and neurophysiologic approaches. It is sincerely hoped that this series of review articles can promote an understanding of the meridian system and acupuncture mechanisms to help patients in a logical and passionate way.

The Neural Mechanism by Which the Dorsal Vagal Complex Mediates the Regulation of the Gastric Motility by Weishu (RN12) and Zhongwan (BL21) Stimulation

A large number of studies have been conducted to explore the mechanism of Back-Shu and Front-Mu points. While several lines of evidence addressed the acupuncture information of Shu acupoints and Mu acupoints gathering in the spinal cord, whether the convergence is extended to the high centre still remains unclear. The study selected gastric Mu points (RN12) and gastric Shu points (BL21) regulating gastric motility and its central neural mechanisms as the breakthrough point, using the technique of immunochemistry, nuclei lesion, electrophysiology, and nerve transection. Here, we report that gastric motility regulation of gastric Shu and Mu acupoints and their synergistic effect and the signals induced by electroacupuncture (EA) stimulation of acupoints RN12 and RN12 gather in the dorsal vagal complex (DVC), increasing the levels of gastrointestinal hormones in the DVC to regulate gastric motility through the vagus. In sum, our data demonstrate an important role of DVC and vagus in the regulation of gastric motility by EA at gastric Shu and Mu points.

Additional evidence for the sustained effect of acupuncture at the vision-related acupuncture point, GB37

OBJECTIVE

To investigate the dynamics underlying the sustained effect of acupuncture as a possible explanation of earlier findings that acupuncture stimulation at the vision-related acupuncture point, GB37, cannot specifically change the functional MRI (fMRI) signals of the visual cortex compared with stimulation at an adjacent non-meridian point.

METHODS

The 'on-off' experimental design was separated into four series conditions: 1 min of baseline scanning at the beginning, then two stimulation epochs separated by a 50 s 'rest' period, and then a 1 min 'rest' epoch. The standard General Linear Model (GLM) approach and multi-conditions analysis were used.

RESULTS

Results from the multi-conditions analysis were different from those from the standard GLM analysis. We found that the neural signal of the limbic-paralimbic-neocortical system after acupuncture stimulus lasted longer than the putative period. Furthermore, the fMRI signal changes in the occipital cortex showed different temporal patterns between GB37 and the non-meridian point.

CONCLUSIONS

Owing to the sustained effect of acupuncture, standard GLM analysis may be unsuitable for 'on-off' design acupuncture studies and lead to uncertain and contradictory results. The findings from this study suggest that acupuncture at GB37 can induce complex brain activity in the vision cortex. The state-related neural signal may reflect one of the significant characteristics underlying acupuncture.

Electroacupuncture alleviates affective pain in an inflammatory pain rat model

Pain has both sensory-discriminative and emotional-affective dimensions. Previous studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension but do not address the affective. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance (CPA) test to determine whether EA inhibits spontaneous pain-induced affective response and, if so, to study the possibility that rostral anterior cingulate cortex (rACC) opioids underlie this effect. Male Sprague-Dawley rats (250-275 g, Harlan) were used. The rats showed place aversion (i.e. affective pain) by spending less time in a pain-paired compartment after conditioning than during a preconditioning test. Systemic non-analgesic morphine (0.5 and 1.0 mg/kg, i.p.) inhibited the affective reaction, suggesting that the affective dimension is underpinned by mechanisms different from those of the sensory dimension of pain. Morphine at 0.5 and at 1 mg/kg did not induce reward. Rats given EA treatment before pain-paired conditioning at GB 30 showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective dimension. EA treatment did not produce reward or aversive effect. Intra-rACC administration of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP), a selective mu opioid receptor antagonist, but not norbinaltorphimine (nor-BNI), a selective kappa opioid receptor antagonist, blocked EA inhibition of the affective dimension. These data demonstrate that EA activates opioid receptors in the rACC to inhibit pain-induced affective responses and that EA may be an effective therapy for both the sensory-discriminative and the affective dimensions of pain.

Correlating acupuncture FMRI in the human brainstem with heart rate variability

Past neuroimaging studies of acupuncture have demonstrated variable results for important brainstem nuclei. We have employed cardiac-gated fMRI with T1-variability correction to study the processing of acupuncture by the human brain. Furthermore, our imaging experiments collected simultaneous ECG data in order to correlate heart rate variability (HRV) with fMRI signal intensity. Subjects experienced one of three stimulations over a 31.5 minute fMRI run: (1) electro-acupuncture at 2Hz/15Hz over the acupoint ST-36 (2) electro-acupuncture at a sham non-acupoint, or (3) sensory control tapping over ST-36. The ECG was analyzed with power spectral methods for low frequency and high frequency components, which reflect the balance in the autonomic nervous system. The HRV data was then correlated with the time-varying fMRI signal intensity. Our data suggests that fMRI activity in the hypothalamus, the dorsal raphe nucleus, the periaqueductal gray, and the rostroventral medulla showed significant correlation with LF/HF ratio calculated from simultaneous HRV data. The correlation of time-varying fMRI response with physiological parameters may provide insight into connections between acupuncture modulation of the autonomic nervous system and neuroprocessing.

Changes in cytokine expression after electroacupuncture in neuropathic rats

The production of proinflammatory cytokines including interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) plays a key role in chronic pain such as neuropathic pain. We investigated changes in cytokine expression in injured peripheral nerves and dorsal root ganglia (DRG) following electroacupuncture (EA) treatment. Neuropathic pain was induced by peripheral nerve injury to the left hind limb of Sprague-Dawley rats under pentobarbital anesthesia. Two weeks later, the nerve-injured rats were treated by EA for 10 minutes. The expression levels of IL-1β, IL-6, and TNF-α in peripheral nerves and DRG of neuropathic rats were significantly increased in nerve-injured rats. However, after EA, the cytokine expression levels were noticeably decreased in peripheral nerves and DRG. These results suggest that EA stimulation can reduce the levels of proinflamtory cytokines elevated after nerve injury.

Acupuncture alleviates the affective dimension of pain in a rat model of inflammatory hyperalgesia

Although studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension of pain, they have not addressed EA's effect on the affective dimension. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance test to determine EA's effects and its underpinning mechanism on the affective dimension of pain. CFA-injected rats showed place aversion, i.e. the affective dimension of pain, by spending less time in a pain-paired compartment after conditioning than before, while saline-injected rats did not. CFA rats given EA treatment at GB30 before a post-conditioning test showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective response. Intra-rostral anterior cingulate cortex (rACC) administration of a κ-, but not μ-opioid receptor antagonist, blocked EA action. These data demonstrate that EA activates opioid receptors in the rACC to inhibit the affective dimension of pain.

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.

Divergent neural processes specific to the acute and sustained phases of verum and SHAM acupuncture

PURPOSE

To discuss which brain region potentially functioned and switched between the immediate and delayed response of acupuncture.

MATERIALS AND METHODS

A nonrepeated event-related functional MRI (fMRI) design was used to investigate the spatial and temporal patterns of acupuncture effects induced by needling an acupoint ST36 (ACU) and a nonmeridian point (SHAM). The standard general linear model was used to detect the immediate neural responses of acupuncture. Graph theory analysis was used to characterize the functional integrated network of the acupuncture delayed effect.

RESULTS

Acupuncture induced significant signal changes in the limbic/paralimbic areas, neocortical regions, brainstem, and cerebellum for immediate effect both in ACU and SHAM. Some of these brain regions showed strong functional connectivity for a delayed effect in ACU. Conjunction analysis showed that the insula played a critical role during the overall process of ACU. No overlapping brain regions were found in SHAM.

CONCLUSION

The findings of this study suggested that the delayed effects may reflect a more significant characteristic underlying acupuncture. Given that the insula as a relay station switched between the immediate and delayed response, it suggested that divergent functional connectivity patterns may mediate the acupuncture-related effects for ACU and SHAM.

Electroacupuncture analgesia in rat ankle sprain pain model: neural mechanisms

OBJECTIVES

Acupuncture, an alternative medical therapy with a long history, is appealing because it can activate endogenous analgesic mechanisms by minimally invasive means. The mechanisms of acupuncture, however, are not well understood yet. The following sentence was removed from our original manuscript. One of the major problems impeding understanding of the acupuncture mechanism is lack of experimental models that mimic various forms of persistent pain that respond to acupuncture in humans.

METHODS

In this review, we summarize and discuss previous and recent findings regarding electroacupuncture-induced analgesia in an ankle sprain pain model and the potential underlying mechanisms of acupuncture.

RESULTS

A novel model of ankle sprain pain is introduced recently and the mechanism of electroacupuncture-induced analgesia in this model has been explored. The following sentence was removed from our original manuscript. This model provides a reproducible and quantifiable index of persistent pain at the ankle joint in rats. Acupuncture at a remote site produces long-lasting and powerful analgesia. The consistent analgesic effect of acupuncture in this model has allowed us to pursue the underlying neural mechanisms.

CONCLUSIONS

These studies provide insight into the mechanisms of acupuncture analgesia in one particular form of persistent pain, and hopefully will allow us to expand our knowledge to other painful conditions.

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.

Bilateral acupuncture analgesia observed by quantitative sensory testing in healthy volunteers

BACKGROUND

There is evidence that acupuncture activates different spinal and supraspinal antinociceptive systems, but the specific modulatory effects on the sensory system have not been systematically investigated. In this study, we evaluated the immediate effects of different types of acupuncture on thermal, mechanical, and vibratory sensory thresholds.

METHODS

Twenty-four healthy volunteers (12 men and 12 women, mean age 33.1 years) received 3 different forms of acupuncture in a single-blinded crossover design; these included manual acupuncture, acupuncture with low-frequency electrical stimulation, and acupuncture with high-frequency electrical stimulation. The time between the interventions was 1 week. All forms of acupuncture were applied unilaterally in the leg at standard acupuncture points: spleen 6, spleen 9, stomach 36, and gallbladder 39. The effects of acupuncture were evaluated by systematic quantitative sensory testing (QST) immediately after each intervention. QST was performed on bilateral lower extremities, including thermal and mechanical perception and pain and vibratory thresholds.

RESULTS

The heat pain threshold was increased after manual acupuncture on the treated and untreated side compared with baseline. Low- and high-frequency electrostimulation led to a higher mechanical pain threshold on the treated side compared with baseline and manual acupuncture. The pressure pain threshold was increased by all forms of acupuncture on both sides, with individual changes from baseline ranging from 25% to 52%.

CONCLUSIONS

There were congruent changes on QST after 3 common acupuncture stimulation methods, with possible unilateral as well as bilateral effects.

Physiologic effects of electroacupuncture combined with intramuscular administration of xylazine to provide analgesia in goats

OBJECTIVE

To investigate physiologic effects of electroacupuncture (EA) combined with xylazine administration in goats.

ANIMALS

48 healthy crossbred goats.

PROCEDURES

Goats were randomly allotted to 8 groups of 3 (nonpregnant and nonlactating) female goats and 3 male goats each. The 8 treatment groups were as follows: 1 EA group, 3 xylazine (0.1, 0.2, and 0.4 mg/kg, IM) groups, 3 EA plus xylazine (0.1, 0.2, and 0.4 mg/kg, IM) groups, and 1 control group. Electroacupuncture was performed for 90 minutes. Xylazine was administered 20 minutes after EA was performed. Pain threshold, heart rate, mean arterial pressure (MAP), respiration rate, and rectal temperature were observed at 0, 5, 25, 45, 65, and 85 minutes after xylazine administration.

RESULTS

Xylazine administered at 0.4 mg/kg increased the pain threshold and reduced MAP. Xylazine administered at 0.1, 0.2, or 0.4 mg/kg reduced heart rate, respiration rate, and temperature. Electroacupuncture increased the pain threshold but had no effect on heart rate, MAP, respiratory rate, or rectal temperature. Pain threshold in goats that underwent EA plus xylazine administration was higher than in goats that received EA or xylazine alone. Electroacupuncture combined with xylazine at 0.1 mg/kg did not affect heart rate, MAP, respiratory rate, or rectal temperature. Pain threshold in goats that underwent EA plus xylazine administration at 0.1 mg/kg was higher than in goats given xylazine at 0.4 mg/kg alone.

CONCLUSIONS AND CLINICAL RELEVANCE

Electroacupuncture combined with xylazine, even at 0.1 mg/kg, provided analgesia without significantly affecting cardiorespiratory parameters or rectal temperature in goats.

Correspondence of the auricular acupoint with the upper trapezius muscle: a electromyographic study

Presently, acupuncture is a technique considered to be capable of stimulating the regulatory systems of the organism, such as the central nervous system, the endocrine system and the immunological system. The median frequency of the upper trapezium muscle with 40% and 60% of maximal voluntary contraction (MVC) of 15 healthy volunteers, was analyzed after the individuals were submitted to the AA treatment. The non-parametric Friedman test was used to compare median frequency values. In this exploratory study, the level of significance of each comparison was set to p<0.05. The intraclass analyses indicate a significant increase of the median frequency muscle at 60% of the MVC (Wicoxon test). Based on the results found, the AA peripheral stimulus can act as a modulator mechanism of muscle activity and was possible to verify correspondence of the auricular acupoint with the trapezius muscle.

Time-variant fMRI activity in the brainstem and higher structures in response to acupuncture

Acupuncture modulation of activity in the human brainstem is not well known. This structure is plagued by physiological artifact in neuroimaging experiments. In addition, most studies have used short (<15 min) block designs, which miss delayed responses following longer duration stimulation. We used brainstem-focused cardiac-gated fMRI and evaluated time-variant brain response to longer duration (>30 min) stimulation with verum (VA, electro-stimulation at acupoint ST-36) or sham point (SPA, non-acupoint electro-stimulation) acupuncture. Our results provide evidence that acupuncture modulates brainstem nuclei important to endogenous monoaminergic and opioidergic systems. Specifically, VA modulated activity in the substantia nigra (SN), nucleus raphe magnus, locus ceruleus, nucleus cuneiformis, and periaqueductal gray (PAG). Activation in the ventrolateral PAG was greater for VA compared to SPA. Linearly decreasing time-variant activation, suggesting classical habituation, was found in response to both VA and SPA in sensorimotor (SII, posterior insula, premotor cortex) brain regions. However, VA also produced linearly time-variant activity in limbic regions (amygdala, hippocampus, and SN), which was bimodal and not likely habituation--consisting of activation in early blocks, and deactivation by the end of the run. Thus, acupuncture induces different brain response early, compared to 20-30 min after stimulation. We attribute the fMRI differences between VA and SPA to more varied and stronger psychophysical response induced by VA. Our study demonstrates that acupuncture modulation of brainstem structures can be studied non-invasively in humans, allowing for comparison to animal studies. Our protocol also demonstrates a fMRI approach to study habituation and other time-variant phenomena over longer time durations.

Neurophysiologic basis of Back-Shu and Huatuo-Jiaji points

Acupuncture, a method of traditional Chinese medicine that uses Back-Shu and Huatuo-Jiaji points, is especially effective for treating diseases of the visceral organs. Applying acupuncture on Back-Shu points affects visceral organs in many ways. For example, it dilates the bronchus, affects the heartbeat, stomach motility, urinary bladder contractions and so on. Acupuncture's effects can be explained as viscero-cutaneous, cutaneo-visceral, cutaneo-muscular, and viscero-muscular reflexes. Segmental dispersion of the sympathetic and parasympathetic systems is related to the location of Back-Shu points. Changes in visceral organs caused by application of acupuncture can be explained as modulation of the sympathetic and parasympathetic systems.

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.

The role of acupuncture in the management of subfertility

OBJECTIVE

To review systematically the use of acupuncture in the management of subfertility.

DESIGN

A computer search was performed via several English and Chinese databases to identify journals relevant to the subject.

RESULT(S)

The positive effect of acupuncture in the treatment of subfertility may be related to the central sympathetic inhibition by the endorphin system, the change in uterine blood flow and motility, and stress reduction. Acupuncture may help restore ovulation in patients with polycystic ovary syndrome, although there are not enough randomized studies to validate this. There is also no sufficient evidence supporting the role of acupuncture in male subfertility, as most of the studies are uncontrolled case reports or case series in which the sample sizes were small. Despite these deficiencies, acupuncture can be considered as an effective alternative for pain relief during oocyte retrieval in patients who cannot tolerate side effects of conscious sedation. The pregnancy rate of IVF treatment is significantly increased, especially when acupuncture is administered on the day of embryo transfer.

CONCLUSION(S)

Although acupuncture has gained increasing popularity in the management of subfertility, its effectiveness has remained controversial.

[Electrical point stimulation (P-STIM) via ear acupuncture: a randomized, double-blind, controlled pilot study in patients undergoing laparoscopic nephrctomyX]

AIM

The aim of this study was to determine whether P-STIM-verum in patients undergoing laparoscopic nephrectomies resulted in a lower consumption of analgesics and an improvement of pain scores compared with P-STIM-placebo when administered for acute peri- and postperative pain.

METHODS

The study was carried out in a double-blind, randomized, controlled manner. Forty-four patients were randomised into 2 groups. The P-STIM device was applied to each patient 30 minutes pro-operatively. The Stimulation was applied over 96 hours. The P-STIM-verum group received subthreshold stimulation. The P-STIM-placebo group received no stimulation. Premedication and anaesthesia were applied in a standardised fashion. The efficacy of treatment was evaluated using a postoperative visual analogue scale (at rest and on exertion) and by dermining postoperative analgesic consumption.

RESULTS

The P-STIM-verum group demonstrated better visual analogue at rest and on exertion then the P-STIM-placebo group. The postoperative consumption of morphine-hydrochloride in the first 6 h significantly less in the P-STIM-verum group. The time of first analgesic request was significantly later in the P-STIM-verum group compared with the P-STIM-placebo group.

CONCLUSIONS

In this study we were able to demonstrate, that pre- and postoperative P-STIM applied in patients undergoing laparoscopic nephrectomies seems to be an effective, simply applied method with few side-effects for reducing pain and postoperative analgesic consumption.

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.

Neural mechanism of acupuncture-modulated gastric motility

AIM: To investigate the acupuncture-modulated gastric motility and its underlying neural mechanism.

METHODS: Intragastric pressure and/or waves of gastric contraction in rats were recorded by intrapyloric balloon and changes of gastric motility induced by acupuncture stimulation were compared with the background activity before any stimulation. Gastro-vagal or splanchnic-sympathetic nerves were recorded or cut respectively for investigating the involvement of autonomic nerve pathways. Spinalization experiment was also performed.

RESULTS: Acupuncture-stimulation by exciting Aδ and/or C afferent fibers, could only modulate gastric motility. Acupuncture-stimulation on fore- and hind-limbs evoked a moderate gastric motility followed by increased vagus discharges with unchanged sympathetic activity, while the same stimulus to the acupoints in abdomen resulted in reversed effects on gastric motility and autonomic nervous activities. The inhibitory gastric response was completely abolished by splanchnic denervation, but the facilitative gastric response to stimulation of acupoints in limbs was not influenced, which was opposite to the effect when vagotomy was performed. The similar depressive effects were produced by the stimulation at the acupoints homo-segmental to the gastric innervation in the animals with or without spinalization. However, the facilitation induced by the stimulation at the acupoints hetero-segmental to the gastric innervation was not observed in the spinalized animals.

CONCLUSION: Facilitative effects of stimulating hetero-segmental acupoints are involved in the intact preparation of vagal nerves and spinal cord, while the inhibitory response induced by stimulating homo-segmental acupoints is involved in the intact preparation of sympathetic nerves. Only the acupuncture-stimulation with intensity over the threshold of Aδ and/or C afferent fibers can markedly modulate gastrointestinal motility.

Policy for therapeutic acupuncture in an academic health center: a model for standard policy development

Acupuncture as a therapeutic modality offers multiple applications. Its effectiveness coupled with its general acceptance by conventional health care professionals makes it one of the first complementary and alternative medicine (CAM) modalities to be incorporated in an integrative approach to care. However, few centers that offer acupuncture have written standard policies to regulate its use. This lack of standard policies may impede provision of quality care, serve as a barrier to cross-institutional data collection and clinical application of that data, and may put health care professionals and institutions at risk when credentialing or malpractice liability has not been clearly addressed. Here we present a policy for acupuncture, created by a diverse group of health care professionals at the University of Michigan Health System. It may function as a generalizable template for standard policy development by institutions incorporating acupuncture.

Effective regularity in modulation on gastric motility induced by different acupoint stimulation

AIM: To investigate whether manual acupuncture at representative acupoints in different parts of the body can modulate responses of gastric motility in rats and regular effects in different acupoint stimulation.

METHODS: The gastric motor activity of rats was recorded by the intrapyloric balloon. The changes of gastric motility induced by the stimulation were compared with the background activity in intragastric pressure and/or waves of gastric contraction recorded before any stimulation. Morphological study was also conducted by observing the Evans dye extravasation in the skin after mustard oil injection into the intragastric mucous membrane to certify cutaneous innervations of blue dots related to gastric segmental innervations.

RESULTS: In all six rats that received mustard oil injections into intragastric mucosa, small blue dots appeared in the skin over the whole abdomen, but mainly in peri-midline upper- and middle- abdomen and middle-back, a few in thigh and groin. It may speculate that cutaneous innervations of blue dots have the same distribution as gastric segmental innervations. Acu-stimulation in acupoints of head-neck, four limbs, upper chest-dorsum and lower-dorsum induced markedly augmentation of gastric motility (acupoints on head-neck such as St-2: n = 16, 105.19 ± 1.36 vs 112.25 ± 2.02 and St-3: n = 14, 101.5 ± 1.75 vs 109.36 ± 1.8; acupoints on limbs such as Sp-6: n = 19, 100.74 ± 1.54 vs 110.26 ± 3.88; St-32: n = 17, 103.59 ± 1.64 vs 108.24 ± 2.41; St-36: n = 16, 104.81 ± 1.72 vs 110.81 ± 2.74 and Li-11: n = 17, 106.47 ± 2.61 vs 114.77 ± 3.77, P < 0.05-0.001). Vigorous inhibitory regulations of gastric motility induced by acu-stimulation applied in acupoints on whole abdomen and middle-dorsum were significantly different as compared with the controls before acu-stimulation (abdomen acupoints such as Cv-12: n = 11, 109.36 ± 2.09 vs 101 ± 2.21; Cv-6: n = 18, 104.39 ± 1.42 vs 91.83 ± 3.22 and St-21: n = 12, 107 ± 2.97 vs 98.58 ± 2.81; acupoints on middle-dorsum such as Bl-17: n = 19, 100.63 ± 1.4 vs 92.21 ± 2.07 and Bl-21: n = 19, 103.84 ± 1.48 vs 97.58 ± 2.16, P < 0.05-0.001).

CONCLUSION: Regular regulatory effects of facilitation and inhibition on gastric motility appear to be somatotopically organized in the acupoints of whole body, and the effective regularity of site-special acupoints on gastric motility is involved in segmental innervations between stomach and acupoints.

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.

Antiallodynic effects of acupuncture in neuropathic rats

Peripheral nerve injury often results in abnormal neuropathic pain such as allodynia or hyperalgesia. Acupuncture, a traditional Oriental medicine, has been used to relieve pain and related symptoms. However, the efficiency of acupuncture in relieving neuropathic pain is not clear. The aim of this study was to investigate the anti-allodynic effects of acupuncture through behavioral and electrophysiological examinations. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves, under pentobarbital anesthesia. The acupuncture experiment consisted of four different groups, one treated at each of three different acupoints (Zusanli (ST36), Yinlingquan (SP9), and a sham-acupoint) and a control group. Behavioral tests for mechanical allodynia and cold allodynia were performed for up to two weeks postoperatively. Extracellular electrophysiological recordings were made from the dorsal roots using platinum wire electrodes. Mechanical and cold allodynia were significantly reduced after acupuncture treatment at the Zusanli and Yinlingquan acupoints, respectively. Electrophysiological neural responses to von Frey and acetone tests were also reduced after acupuncture at the same two acupoints. These results suggest that acupuncture may be beneficial in relieving neuropathic pain.

The potential of a person-centered approach in caring for patients with cancer: a perspective from the UCLA center for East-West medicine

BACKGROUND

Evolving patient preferences as well as an expanding evidence base for commonly used complementary and alternative medicine therapies for patients with cancer have led to inroads by integrative medicine into clinical oncology. Traditional Chinese medicine (TCM) has been used in conjunction with conventional biomedicine in the prevention and treatment of cancer in China for several decades.

METHODS

The authors, through select review of the existing literature and by drawing on clinical experience, describe a person-centered approach to care of patients with cancer that incorporates TCM concepts and techniques. Two cases are used to illustrate how this approach might address unmet needs and enhance quality of life for patients with cancer.

RESULTS

TCM's emphasis on a comprehensive understanding of imbalance in various systems and resultant compromise of homeostatic reserve as well as its ability to treat them with distinctive therapeutic modalities can add unique value to the overall management of the patient with cancer.

CONCLUSIONS

TCM can be used adjunctively to improve quality of life and functional status during a patient's struggle with cancer. An approach integrating both medicines that is guided by scientific evidence, safety, and patient preferences has the potential to improve modern oncologic care.

Auricular electro-acupuncture as an additional perioperative analgesic method during oocyte aspiration in IVF treatment

BACKGROUND

The aim of this study was to compare the pain-relieving effect and the subjective well-being between auricular electro-acupuncture (EA) analgesia, auricular acupuncture (A) and conventional analgesia with remifentanil (CO).

METHODS

A total of 94 women undergoing IVF were randomized to auricular acupuncture with (EA, n = 32) or without (A, n = 32) continuous 1 Hz auricular stimulation (using a battery-powered miniaturized stimulator, P-Stim) or with adhesive tapes instead of needles and no electrical stimulation (control group, CO, n = 30) at the auricular acupuncture points 29, 55 and 57. All patients received patient-controlled analgesia (PCA) with remifentanil. Pain intensity and psychological well-being were assessed by means of visual analogue scales (VAS); tiredness, nausea and vomiting and analgesic drug consumption were documented.

RESULTS

Pain relief and subjective well-being were significantly greater in group EA during and after the procedure as compared with groups A and CO (P < 0.001). The patients were significantly more tired in group CO than in groups A and EA (P < 0.001). Consumption of the opioid remifentanil was significantly lower in group EA, comparable nausea (P < 0.001).

CONCLUSION

Auricular EA significantly reduces pain intensity and analgesic consumption of the opioid remifentanil during oocyte aspiration in IVF treatment.

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.

Acupuncture inhibition on neuronal activity of spinal dorsal horn induced by noxious colorectal distention in rat

AIM: To observe how acupuncture stimulation influences the visceral nociception in rat and to clarify the interactions between acupuncture or somatic input and visceral nociceptive inputs in the spinal dorsal horn. These will provide scientific base for illustrating the mechanism of acupuncture on visceral pain.

METHODS: Experiments were performed on Sprague-Dawley rats and the visceral nociceptive stimulus was generated by colorectal distention (CRD). Unit discharges from individual single neuron were recorded extracellularly with glass-microelectrode in L_1-3 spinal dorsal horn. Acupuncture stimulation was applied at contralateral heterotopic acupoint and ipsilateral homotopic acupoint, both of which were innervated by the same segments that innervate also the colorectal-gut.

RESULTS: The visceral nociception could be inhibited at the spinal level by the heterotopic somatic mechanical stimulation and acupuncture. The maximal inhibition was induced by acupuncture or the somatic noxious stimulation at spinal dorsal horn level with inhibiting rate of 68.61% and 60.79%, respectively (P<0.01 and <0.001). In reversible spinalized rats (cervical-thoracic cold block) both spontaneous activity and responses to CRD increased significantly in 16/20 units examined, indicating the existence of tonic descending inhibition. The inhibition of acupuncture on the noxious CRD disappeared totally in the reversible spinalized rats (P<0.001).

CONCLUSION: The inputs of noxious CRD and acupuncture may interact at the spinal level. The nociceptive visceral inputs could be inhibited by acupuncture applied to hetero-topic acupoint. The effect indicates that the spinal dorsal horn plays a significant role in mediating the inhibition of acupuncture and somatic stimulation on the neuronal response to the noxious visceral stimulation and the inhibition is modulated by upper cervical cord and/or supra-spinal center.