Inhibitory effects of electroacupuncture on stress responses evoked by tooth-pulp stimulation in rats

Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives

The hypothalamic-pituitary-adrenal (HPA) axis is a critical component of the neuroendocrine system, playing a central role in regulating the body's stress response and modulating various physiological processes. Dysregulation of HPA axis function disrupts the neuroendocrine equilibrium, resulting in impaired physiological functions. Acupuncture is recognized as a non-pharmacological type of therapy which has been confirmed to play an important role in modulating the HPA axis and thus favorably targets diseases with abnormal activation of the HPA axis. With numerous studies reporting the promising efficacy of acupuncture for neuroendocrine disorders, a comprehensive review in terms of the underlying molecular mechanism for acupuncture, especially in regulating the HPA axis, is currently in need. This review fills the need and summarizes recent breakthroughs, from the basic principles and the pathological changes of HPA axis dysfunction, to the molecular mechanisms by which acupuncture regulates the HPA axis. These mechanisms include the modulation of multiple neurotransmitters and their receptors, neuropeptides and their receptors, and microRNAs in the paraventricular nucleus, hippocampus, amygdala and pituitary gland, which alleviate the hyperfunctioning of the HPA axis. This review comprehensively summarizes the mechanism of acupuncture in regulating HPA axis dysfunction for the first time, providing new targets and prospects for further exploration of acupuncture. Please cite this article as: Zheng JY, Zhu J, Wang Y, Tian ZZ. Effects of acupuncture on hypothalamic-pituitary-adrenal axis: Current status and future perspectives. J Integr Med. 2024; 22(4): 446-459.

Regulatory Role of Orexin in the Antistress Effect of "Press Tack Needle" Acupuncture Treatment

The aim of this research was to investigate the antistress effect of press tack needle (PTN) acupuncture treatment using rats with social isolation stress (SIS). Rats were divided into non-stress group (Grouped+sham), stress group (SIS+sham), and PTN-treated SIS group (SIS+PTN). Rats in the SIS+PTN and SIS+sham groups were housed alone for eight days. For the SIS+PTN group, a PTN (length, 0.3 or 1.2 mm) was fixed on the GV20 acupoint on day 7. We measured stress behavior based on the time the rats showed aggressive behavior and the levels of plasma corticosterone and orexin A on day 8. In addition, the orexin-1 receptor or orexin-2 receptor antagonist was administered to rats that were exposed to SIS. The duration of aggressive behavior was significantly prolonged in the SIS+sham group, and the prolonged duration was inhibited in the SIS+PTN (1.2 mm) group. The levels of plasma corticosterone and orexin A were significantly increased in the SIS+sham group; however, these increases were inhibited in the SIS+PTN group. The aggressive behavior was significantly reduced after the orexin-2 receptor antagonist was administered. These findings suggest that PTN treatment at GV20 may have an antistress effect, and the control of orexin is a mechanism underlying this phenomenon.

Acupuncture and Chronic Musculoskeletal Pain

PURPOSE OF REVIEW

Chronic musculoskeletal pain (CMP) attributable to conditions such as osteoarthritis, rheumatoid arthritis, fibromyalgia, and chronic low back pain is the most common cause of disability globally, for which no effective remedy exists. Although acupuncture is one of the most popular sensory stimulation therapies and is widely used in numerous pain conditions, its efficacy remains controversial. This review summarizes and expands upon the current research on the therapeutic properties of acupuncture for patients with CMP to better inform clinical decision-making and develop patient-focused treatments.

RECENT FINDINGS

We examined 16 review articles and 11 randomized controlled trials published in the last 5 years on the clinical efficacy of acupuncture in adults with CMP conditions. The available evidence suggests that acupuncture does have short-term pain relief benefits for patients with symptomatic knee osteoarthritis and chronic low back pain and is a safe and reasonable referral option. Acupuncture may also have a beneficial role for fibromyalgia. However, the available evidence does not support the use of acupuncture for treating hip osteoarthritis and rheumatoid arthritis. The majority of studies concluded the superiority of short-term analgesic effects over various controls and suggested that acupuncture may be efficacious for CMP. These reported benefits should be verified in more high-quality randomized controlled trials.

Physiologic and biochemical effects of electroacupuncture combined with intramuscular administration of dexmedetomidine to provide analgesia in goats

OBJECTIVE

To investigate physiologic and biochemical effects of electroacupuncture and dexmedetomidine administration to goats.

ANIMALS

30 healthy adult goats.

PROCEDURES

Goats were allotted to 5 groups (6 goats/group) and received electroacupuncture, dexmedetomidine (5 or 20 μg/kg, IM), electroacupuncture plus dexmedetomidine (5 μg/kg, IM), or saline (0.9% NaCl) solution (IM [control treatment]). Pain threshold, cardiorespiratory effects, rectal temperature, and hematologic and biochemical variables were assessed.

RESULTS

Dexmedetomidine (20 μg/kg) increased pain threshold and decreased heart rate, respiratory rate, and rectal temperature. Pain threshold of goats receiving electroacupuncture plus dexmedetomidine (5 μg/kg) was higher than that of goats receiving electroacupuncture or of goats receiving dexmedetomidine at 5 μg/kg at 30 minutes, but did not differ from that of goats receiving dexmedetomidine at 20 μg/kg. Compared with goats administered dexmedetomidine at 20 μg/kg, goats receiving electroacupuncture plus dexmedetomidine at 5 μg/kg had a higher heart rate from 30 to 60 minutes and a higher respiratory rate from 5 to 60 minutes. Electroacupuncture plus dexmedetomidine (5 μg/kg) did not affect rectal temperature. Serum glucose concentrations of goats receiving electroacupuncture plus dexmedetomidine (5 μg/kg) were higher than for goats receiving dexmedetomidine at 5 μg/kg at 30 minutes but not for goats receiving dexmedetomidine at 20 μg/kg. Creatinine and BUN concentrations, alanine or aspartate aminotransferase activities, and hematologic variables of treated goats did not change.

CONCLUSIONS AND CLINICAL RELEVANCE

Electroacupuncture in combination with a low dose of dexmedetomidine (5 μg/kg, IM) administered to goats provided antinociception.

Acupuncture Affects Autonomic and Endocrine but Not Behavioural Responses Induced by Startle in Horses

Startle is a fast response elicited by sudden acoustic, tactile, or visual stimuli in a variety of animals and in humans. As the magnitude of startle response can be modulated by external and internal variables, it can be a useful tool to study reaction to stress. Our study evaluated whether acupuncture can change cardiac autonomic modulation (heart rate variability); and behavioural (reactivity) and endocrine (cortisol levels) parameters in response to startle. Brazilian Sport horses (n = 6) were subjected to a model of startle in which an umbrella was abruptly opened near the horse. Before startle, the horses were subjected to a 20-minute session of acupuncture in acupoints GV1, HT7, GV20, and BL52 (ACUP) and in nonpoints (NP) or left undisturbed (CTL). For analysis of the heart rate variability, ultrashort-term (64 s) heart rate series were interpolated (4 Hz) and divided into 256-point segments and the spectra integrated into low (LF; 0.01–0.07 Hz; index of sympathetic modulation) and high (HF; 0.07–0.50 Hz; index of parasympathetic modulation) frequency bands. Acupuncture (ACUP) changed the sympathovagal balance with a shift towards parasympathetic modulation, reducing the prompt startle-induced increase in LF/HF and reducing cortisol levels 30 min after startle. However, acupuncture elicited no changes in behavioural parameters.

Acupuncture blocks cold stress-induced increases in the hypothalamus-pituitary-adrenal axis in the rat

Electroacupuncture (EA) is used to treat chronic stress; however, its mechanism(s) of action in allaying stress remains unclear. The interplay of stress hormones of the hypothalamus-pituitary-adrenal axis (HPA) and the sympathetic nervous system (SNS) is critical in the stress response. Our objective was to determine whether EA at acupoint, stomach 36 (EA St₃₆) is effective in preventing chronic cold stress-induced increased hormone levels in the rat by examining four groups of animals, three of which were exposed to cold and one of which was a non-treatment control group. Before exposure to the cold, two groups were treated with either EA St₃₆, or Sham-EA, before 10 days of cold stress. The EA St₃₆ animals demonstrated a significant decrease in peripheral HP hormones (ACTH and CORT) compared with stress animals (P<0.05). These effects were specific; rats receiving Sham-EA had elevation of these hormones, similar to the stress-only animals. These effects were mirrored centrally in the brain; CRH levels were significantly (P<0.05) reduced in EA St₃₆ animals compared with the other animals. Finally, EA effect on peripheral and adrenal SNS hormones (norepinephrine (NE) and neuropeptide Y (NPY) respectively) was examined, with no significant difference noted in adrenal tyrosine hydroxylase or circulating NE in any of the groups. However, EA St₃₆ was effective in preventing stress-induced elevation is adrenal Npy mRNA. These results indicate that EA St₃₆ blocks the chronic stress-induced elevations in the HPA and the sympathetic NPY pathway, which may be a mechanism for its specific stress-allaying effects.

Effect and mechanism of acupuncture on gastrointestinal diseases

Acupuncture modulates various biomechanical responses, such as prokinetic, antiemetic, and antinociceptive effects. Acupuncture treatment involves the insertion of thin needles into the skin and underlying muscle and the needles are stimulated manually or electrically. Thus, acupuncture stimulates the somatic afferent nerves of the skin and muscles. The somatic sensory information from the body is carried to the cortex area of the brain. Somatic sensory fibers also project to the various nuclei, including the brain stem, periaqueductal gray (PAG), and paraventricular nucleus (PVN) of the hypothalamus. Somatosensory pathways stimulated by acupuncture activate these nuclei. Activation of the brain stem modulates the imbalance between sympathetic activity and parasympathetic activity. Opioid released from the PAG is involved in mediating antiemetic and antinociceptive effects of acupuncture. Oxytocin release from the PVN mediates antistress and antinociceptive effects of acupuncture. Acupuncture may be effective in patients with functional gastrointestinal (GI) disorders because of its effects on GI motility and visceral pain. It is expected that acupuncture is used in the treatment of patients with functional GI disorders.

Anti-stress effects of transcutaneous electrical nerve stimulation (TENS) on colonic motility in rats

BACKGROUND

Disorders of colonic motility may contribute to symptoms in patients with irritable bowel syndrome (IBS), and stress is widely believed to play a major role in developing IBS. Stress increases corticotropin releasing factor (CRF) of the hypothalamus, resulting in acceleration of colonic transit in rodents. In contrast, hypothalamic oxytocin (OXT) has an anti-stress effect via inhibiting CRF expression and hypothalamic-pituitary-adrenal axis activity. Although transcutaneous electrical nerve stimulation (TENS) and acupuncture have been shown to have anti-stress effects, the mechanism of the beneficial effects remains unknown.

AIMS

We tested the hypothesis that TENS upregulates hypothalamic OXT expression resulting in reduced CRF expression and restoration of colonic dysmotility in response to chronic stress.

METHODS

Male SD rats received different types of stressors for seven consecutive days (chronic heterotypic stress). TENS was applied to the bilateral hind limbs every other day before stress loading. Another group of rats did not receive TENS treatment.

RESULTS

TENS significantly attenuated accelerated colonic transit induced by chronic heterotypic stress, which was antagonized by a central injection of an OXT antagonist. Immunohistochemical study showed that TENS increased OXT expression and decreased CRF expression at the paraventricular nucleus (PVN) following chronic heterotypic stress.

CONCLUSIONS

It is suggested that TENS upregulates hypothalamic OXT expression which acts as an anti-stressor agent and mediates restored colonic dysmotility following chronic stress. TENS may be useful to treat gastrointestinal symptoms associated with stress.

Neural acupuncture unit: a new concept for interpreting effects and mechanisms of acupuncture

When an acupuncture needle is inserted into a designated point on the body and mechanical or electrical stimulation is delivered, various neural and neuroactive components are activated. The collection of the activated neural and neuroactive components distributed in the skin, muscle, and connective tissues surrounding the inserted needle is defined as a neural acupuncture unit (NAU). The traditionally defined acupoints represent an anatomical landmark system that indicates local sites where NAUs may contain relatively dense and concentrated neural and neuroactive components, upon which acupuncture stimulation would elicit a more efficient therapeutic response. The NAU-based local mechanisms of biochemical and biophysical reactions play an important role in acupuncture-induced analgesia. Different properties of NAUs are associated with different components of needling sensation. There exist several central pathways to convey NAU-induced acupuncture signals, Electroacupuncture (EA) frequency-specific neurochemical effects are related to different peripheral and central pathways transmitting afferent signals from different frequency of NAU stimulation. More widespread and intense neuroimaging responses of brain regions to acupuncture may be a consequence of more efficient NAU stimulation modes. The introduction of the conception of NAU provides a new theoretical approach to interpreting effects and mechanisms of acupuncture in modern biomedical knowledge framework.

Acupuncture at ST36 prevents chronic stress-induced increases in neuropeptide Y in rat

Chronic stress, as seen in post-traumatic stress disorder, can exacerbate existing diseases. Electroacupuncture (EA) has been proposed to treat chronic stress, although information on its efficacy or mechanism(s) of action is limited. While many factors contribute to the chronic stress response, the sympathetic peptide, neuropeptide Y (NPY), has been shown to be elevated in chronic stress and is hypothesized to contribute to the physiological stress response. Our objective was to determine if EA at acupuncture point stomach 36 (ST36) is effective in mitigating cold stress-induced increase in NPY in rats. Both pretreatment and concomitant treatment with EA ST36 effectively suppressed peripheral and central NPY after 14 d of cold stress ( P < 0.05). The effect was specific, as NPY in Sham-EA rats was not different than observed in stress-only rats. Additionally, the effect of EA ST36 was long-lasting, as NPY levels remained suppressed despite early cessation of EA ST36, while exposure to cold stress was continued. In the paraventricular nucleus (PVN), it was notable that changes in NPY mirrored plasma NPY levels, and that the significant elevation in PVN Y1 receptor observed with stress was also prevented with EA ST36. The findings indicate that EA ST36 is effective in preventing one of the sympathetic pathways stimulated during chronic stress, and thus may be a useful adjunct therapy in stress-related disorders.

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.

Acupuncture for posttraumatic stress disorder: conceptual, clinical, and biological data support further research

Posttraumatic stress disorder (PTSD) is common, debilitating, and has highly heterogeneous clinical and biological features. With the exception of one published preliminary clinical trial, rationale in support of the efficacy of acupuncture, a modality of Chinese medicine (CM), for PTSD has not been well described. This is a focused review of conceptual and clinical features of PTSD shared by modern western medicine (MWM) and CM, and of biological mechanisms of acupuncture that parallel known PTSD pathology. MWM and CM both recognize individual developmental variables and interactions between external conditions and internal responses in the genesis of PTSD. There is one published and one unpublished clinical trial that preliminarily support the efficacy of acupuncture for PTSD. Although there have been no mechanistic studies of acupuncture in human PTSD, extant research shows that acupuncture has biological effects that are relevant to PTSD pathology. Conceptual, clinical, and biological data support possible efficacy of acupuncture for PTSD. However, further definitive research about simultaneous clinical and biological effects is needed to support the use of acupuncture for PTSD in health care systems.

Mechanism of acupuncture on neuromodulation in the gut--a review

INTRODUCTION

Acupuncture has been used for treating various gastrointestinal (GI) diseases. However, the mechanism of acupuncture remains unclear.

METHODS

The aim of this article is to review the published literature on the mechanism of acupuncture on neuromodulation in the gut.

RESULTS

Acupuncture treatment involves the insertion of thin needles into the skin and underlying muscle and the subsequent stimulation of the needles manually or electrically. Thus, acupuncture stimulates the somatic afferent nerves of the skin and muscles. The somatic sensory information from the body is carried to the cortex area of the brain. Somatic sensory fibers also project to the various nuclei at the brain stem and hypothalamus. Via somato-autonomic reflex, acupuncture modulates various biomechanical responses, such as prokinetic, antiemetic, and anti-nociceptive effects.

CONCLUSION

According to traditional Chinese medicine, "Acupuncture is believed to restore the balance of Yin and Yang." This can be translated into the Western medicine terminology that "Acupuncture modulates the imbalance between the parasympathetic and sympathetic activity." Acupuncture may be effective in patients with functional GI disorders because of its effects on GI motility and visceral pain.

Plasma adrenaline increases in anesthetized patients given electro-acupuncture before surgery

PURPOSE

In anesthetized patients, electro-acupuncture (EA) has been found to reduce sevoflurane-induced suppression of cranial and spinal motor responses to surgery without influencing the level of anesthesia. The underlying mechanisms are unclear. In the present study, blood samples were analyzed to evaluate if the increased clinical motor responses to surgery in patients subjected to EA under sevoflurane anesthesia are also reflected in higher plasma levels of catecholamines, adrenocorticotrophic hormone (ACTH), or cortisol.

METHODS

Blood samples were obtained before anesthetic induction, soon after the study or control procedures had been completed under general anesthesia, and after 30 minutes of surgery under steady-state anesthesia with 1.8% of sevoflurane, in 45 healthy female patients, scheduled for sterilization by laparoscopy, randomized for bilateral 2 Hz-burst EA (study group; n = 22) or control (control group; n = 23) procedures.

RESULT

Plasma levels of adrenaline were found to approach the higher preanesthetic level after 30 minutes of surgery in patients given EA stimulation but to remain low in control patients (P < 0.05)-in agreement with the stronger clinical motor responses to skin incision in the EA group. Plasma levels of noradrenaline, ACTH, and cortisol did not change in or differ between the two groups.

CONCLUSION

The clinical facilitation of both cranial and spinal motor responses to surgery in patients given acupuncture under sevoflurane anesthesia is associated with increased plasma levels of adrenaline, possibly reflecting sympathetic activation.

The effect of electroacupuncture on T cell responses in rats with experimental autoimmune encephalitis

Successive electroacupuncture (EA) stimulation on Zusanli ST36 acupoints of rats with experimental autoimmune encephalitis (EAE), which is an inflammatory disease mediated by autoreactive T cells, relieved disease severity, inhibited specific T cell proliferation and rebuilt the CD4+ T cell subset balance. In addition, EA-treated rats had significantly higher ACTH concentrations in vivo compared to untreated EAE rats. These results indicated that EA stimulation could relieve the severity of EAE by restoring balance to the Th1/Th2/Th17/Treg Th cell subset responses by stimulating the hypothalamus to increase ACTH secretion.

Electroacupuncture improves imbalance of autonomic function under restraint stress in conscious rats

Acupuncture may modulate the imbalance of the autonomic nervous system. It is well known that restraint stress delays gastric emptying via inhibiting parasympathetic activity and/or stimulating sympathetic activity in rats. We have previously shown that electroacupuncture (EA) improves delayed gastric emptying induced by restraint stress in rats. To investigate whether the beneficial effect of EA on delayed gastric emptying is associated with its modulatory effects on autonomic nervous activity, we utilized spectral analysis of heart rate variability (HRV). In rats, the power in the low frequency (LF; 0.04-1.0 Hz) and high frequency (HF; 1.0-3 Hz) band of HRV represent sympathetic and parasympathetic activities, respectively. Electrocardiography (ECG)-electrodes were implanted on the subcutaneous tissues of the back. One week after the surgery, ECG was recorded before, during and after the restraint stress loading in a conscious state. EA (10 Hz) was applied at bilateral acupuncture points [ST-36 (lower leg) or BL-21 (back)] during restraint stress loading. In response to restraint stress, heart rate and LF component were increased, suggesting the increased activity of sympathetic tone. EA at ST-36 significantly reduced the elevated heart rate and LF, compared to that of control group. EA at ST-36 also significantly increased HF component after finishing the stress loading. In contrast, EA at BL-21 had no significant effect on the heart rate, LF and HF. It is suggested that EA at ST-36 stimulates parasympathetic activity and inhibits sympathetic activity under the restraint stress in rats.

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.

Acupuncture for posttraumatic stress disorder: a randomized controlled pilot trial

The purpose of the study was to evaluate the potential efficacy and acceptability of accupuncture for posttraumatic stress disorder (PTSD). People diagnosed with PTSD were randomized to either an empirically developed accupuncture treatment (ACU), a group cognitive-behavioral therapy (CBT), or a wait-list control (WLC). The primary outcome measure was self-reported PTSD symptoms at baseline, end treatment, and 3-month follow-up. Repeated measures MANOVA was used to detect predicted Group X Time effects in both intent-to-treat (ITT) and treatment completion models. Compared with the WLC condition in the ITT model, accupuncture provided large treatment effects for PTSD (F [1, 46] = 12.60; p < 0.01; Cohen's d = 1.29), similar in magnitude to group CBT (F [1, 47] = 12.45; p < 0.01; d = 1.42) (ACU vs. CBT, d = 0.29). Symptom reductions at end treatment were maintained at 3-month follow-up for both interventions. Accupuncture may be an efficacious and acceptable nonexposure treatment option for PTSD. Larger trials with additional controls and methods are warranted to replicate and extend these findings.

The management of cancer-related fatigue after chemotherapy with acupuncture and acupressure: a randomised controlled trial

BACKGROUND

Cancer-related fatigue after chemotherapy is a difficult symptom to manage in practice and the most disruptive symptom in patients' lives. Acupuncture is a popular complementary therapy among cancer patients and some evidence exists that it could potentially alleviate fatigue by stimulating 'energy' points in the body. Hence, this study was carried out to assess the effects of acupuncture and acupressure in managing cancer-related fatigue and the feasibility of running a randomised trial with these two complementary therapies in preparation for a large trial.

METHODS

This study was a randomised controlled trial. Forty-seven patients with cancer who experienced moderate to severe fatigue were randomised either to an acupuncture group (n=15), an acupressure group (n=16) or a sham acupressure group (n=16). The acupuncture group received six 20-min sessions over 2 weeks, while the patients in the two acupressure groups were taught to massage/press the points and did so daily thereafter for 2 weeks on their own. Patients completed the Multidimensional Fatigue Inventory before randomisation, at the end of the 2-week intervention and again about 2 weeks after the end of the intervention.

RESULTS

Significant improvements were found with regards to General fatigue (P<0.001), Physical fatigue (P=0.016), Activity (p=0.004) and Motivation (P=0.024). At the end of the intervention, there was a 36% improvement in fatigue levels in the acupuncture group, while the acupressure group improved by 19% and the sham acupressure by 0.6%. Improvements were observed even 2 weeks after treatments, although they were lower (22%, 15%, 7%, respectively). Acupuncture was a more effective method than acupressure or sham acupressure. Subjects needed a longer treatment period to have more sustained results. The trial was methodologically feasible.

CONCLUSION

Acupuncture shows great potential in the management of cancer-related fatigue. As a randomised trial with acupuncture is feasible and preliminary data shows significant improvements, it should be tested further using a large sample and a multicentre design.

Electroacupuncture elicits dual effects: stimulation of delayed gastric emptying and inhibition of accelerated colonic transit induced by restraint stress in rats

Acupuncture has been used for treating functional gastrointestinal (GI) disorders. Animal studies have demonstrated that acupuncture antagonized various stress-induced responses. We investigated the effects of electroacupuncture (EA) at ST-36 (Zusanli; lower limb) on stress-induced alteration of GI motor activities. Solid gastric emptying was significantly delayed by restraint stress (29.6+/-2.4%; n=7) compared to that of controls (60.0+/-2.5%; n=8). Delayed gastric emptying was significantly improved by EA at ST-36 (47.2+/-1.8%). Intracisternal (IC) injection of corticotropin releasing factor (CRF; 1 microg) delayed gastric emptying to 25.4+/-3.1%, which was also improved by EA at ST-36, to 53.0+/-7.1% (n=8). The stimulatory effect of EA on stress-induced delayed gastric emptying was abolished by atropine (17.6+/-1.9%) but not by guanethidine (42.2+/-2.3%). Colonic transit was significantly accelerated by restraint stress (GC=7.2+/-0.3; n=8) compared to that of controls (GC=5.2+/-0.2; n=8). Accelerated colonic transit was significantly reduced by EA at ST-36 (GC=4.9+/-0.3). IC injection of CRF accelerated colonic transit (GC=6.9+/-0.2), which was also normalized by EA at ST-36 (GC=4.7+/-0.2). The inhibitory effect of EA on stress-induced acceleration of colonic transit was not affected by guanethidine (GC=4.6+/-0.3). In conclusion, EA at ST-36 showed dual effects: stimulation of stress-induced delayed gastric emptying and inhibition of stress-induced acceleration of colonic transit. The stimulatory effect of EA on stress-induced delayed gastric emptying is mediated via cholinergic pathways. The inhibitory effect of EA on stress-induced acceleration of colonic transit is independent of the sympathetic pathway.

Suppression of pain by exposure of acupuncture points to polarized light

BACKGROUND

According to clinical studies, the stimulation of acupuncture points (APs) by a variety of methods (eg, needles, pressure, etc) is an effective method for the treatment of many pain syndromes. However, no experimental proof exists showing that the exposure of APs to low-intensity incoherent polarized (P) light evokes an analgesic affect.

OBJECTIVES

The authors' previous work, using mice, shows that the exposure of APs to low-intensity microwaves effectively decreases pain. The purpose of the present study was to determine whether exposure of APs to low-intensity incoherent P light evokes a statistically significant reduction in pain.

METHODS

The effects of P light on behavioural responses to acute and tonic pain were tested in mice. The threshold of vocalization during electrical stimulation of the foot (acute pain) was measured before and after exposure of AP E-36 to P light. The duration of licking the formalin-injected foot (tonic pain) was investigated in control mice and mice exposed to P light on APs E-36, V-56 and V-60 or on skin that did not contain analgesic APs.

RESULTS

Exposure of APs to P light evoked a statistically significant increase in pain threshold by 34.2% to 59.1%, and shortened the licking time by 32.3% to 50% in mice. The most effective AP was E-36 in both the painful foot and the normal foot. After 2 min, 6 min and 10 min of P light exposure, analgesia was 7.6%, 30.9% and 50%, respectively. The exposure to P light on skin that did not contain analgesic APs did not evoke significant effect.

CONCLUSIONS

The results show the efficacy of pain suppression by exposure of antinociceptive APs to P light.

The association of serum leptin with the reduction of food intake and body weight during electroacupuncture in rats

Previous studies indicate that acupuncture or electroacupuncture (EA) treatment reduces body weight and food intake in rats by increasing the level of anoretic peptides and decreasing that of orexigenic peptides in the hypothalamus. Considering a well-established role of leptin as a major regulator for feeding behavior in the hypothalamus, we hypothesized that EA might exert its effect via increasing serum leptin levels. In this study, we tested our hypothesis by evaluating the effects of EA on food intake and body weight, as well as on serum leptin levels in rats. Rats were randomly divided into 3 groups: AL (fed ad libitum with no treatments), Holder (fed ad libitum with daily holder restraint) and EA (fed ad libitum with daily holder restraint and 100 Hz EA stimulation) groups. During the four-week experimental period, daily food intake and body weight were measured. At the end of the experiment, levels of serum leptin and corticosterone, and plasma epinephrine (Epi) and norepinephrine (NE) were determined. Here we demonstrate that EA treatment indeed led to reduction of food intake and body weight, and to an increase of serum leptin levels. The level of Epi, NE, and corticosterone increased in the Holder group, but such increase in the level of aforementioned stress hormones was not observed in the EA group. Overall, our results suggest that EA treatment reduces food intake and body weight in rats possibly through increasing leptin levels, and that this effect of EA is not due to the stress caused by the daily holder restraint.

Acupuncture Stimulates the Release of Serotonin, but Not Dopamine, in the Rat Nucleus Accumbens

Acupuncture has been introduced as one of the available therapies widely used in alternative medicine, but it has not achieved widespread acceptance with scientific evidence. Furthermore there are still many unanswered questions about the basic mechanisms of acupuncture. To investigate the neuropharmacological mechanisms of oriental acupuncture, we studied the acupuncture-induced changes of in vivo monoamine release in the rat brain. A microdialysis guide cannula was implanted into the nucleus accumbens (ACC), which plays an important role in the brain reward system. Acupuncture treatment at the unilateral or bilateral Shenshu (bladder urinary channel 23) acupoints, located on the both sides of the spinous processes on the lower back, was carried out for 60 min in freely moving rats, and the dopamine (DA) and serotonin (5-HT) contents of the microdialysates in the ACC were measured simultaneously. In rats subjected to acupuncture at bilateral Shenshu acupoints, increases of 5-HT release in the ACC were observed at 20 min of acupuncture treatment and continued until 40 min after acupuncture was ended. Acupuncture at a unilateral Shenshu acupoint increased the release of 5-HT at 20 min compared with that in the sham-control group. Five-HT release returned to the baseline level at 120 min. The effects of acupuncture at bilateral Shenshu acupoints on the release of 5-HT in the ACC were greater than that of unilateral acupuncture treatment. In contrast, DA release in the ACC was not changed following acupuncture treatment. Effective acupuncture increased and prolonged the activity of serotonergic neurons in the reward system pathway of the brain. This suggests that oriental acupuncture therapy may be effective for the treatment of emotional disorders, drug abuse and alcoholism.

Up-regulation of the expression of cocaine and amphetamine-regulated transcript peptide by electroacupuncture in the arcuate nucleus of diet-induced obese rats

It was reported that acupuncture or electro-acupuncture (EA) is effective in reducing the body weight for obese patients, although the mechanisms remain obscure. In a previous study, we have found that rats fed with high-fat (HIF) diet developed diet-induced obesity (DIO) with a concomitant decrease in the hypothalamic content of the cocaine and amphetamine-regulated transcript (CART) peptide, a peptide with anorexiogenic effect. To assess the central effect of EA on DIO rat, we revealed that EA up-regulated the expression of CART peptide in the arcuate nucleus (ARC) of the DIO rats. After feeding with HIF diet for 14 weeks, the DIO rats received EA stimulation three times per week for 4 weeks. The expression of CART peptide in ARC was measured using immunohistochemistry. The plasma ACTH was measured with ELISA. EA caused a reduction of both body weight and energy intake in DIO rats and increased the expression of CART peptide in ARC. The plasma ACTH was increased in response to restraint stress, but EA produced no further increase in ACTH levels. The results suggest that EA can up-regulate the expression of CART peptide to approach normal level, resulting in an inhibition of food intake and a reduction of body weight in DIO rats.

Reduction of excessive electrical stimulus during electric pulp testing

AIM

To measure excessive electrical stimulus time during pulp testing via electromyography (EMG) in the anterior belly of the digastric muscle, voice and finger movement, and to determine whether excessive stimulus time could be attenuated by a specially designed automatic circuit breaker on the basis of the EMG signal.

METHODOLOGY

The signals from three human responses (EMG, finger and voice), induced by the Digitest (Parkell Inc., Farmingdale, NY, USA) electric pulp tester, were captured using a MP100 (Biopac System Inc., Goleta, CA, USA) and recorded into a personal computer. The excessive stimulus time from activation to the end of electrical stimulation was calculated for each of these three responses. The automatic circuit breaker was designed to disconnect the electrical output of the electric pulp testing (EPT) unit immediately after detecting the preset EMG level (100 mV). Each of the right central incisors and first premolars of 23 healthy individuals (16 males and seven females) was tested to see whether there was a difference in tooth type or gender. This was analysed by Wilcoxon signed rank test (nonparametric paired t-test) and Mann-Whitney test (nonparametric independent t-test), respectively.

RESULTS

Amongst three human responses, the electrical onset occurred in the order of EMG, finger and voice. Excessive stimulus time was 347.8 +/- 78.3 ms when observed by the EMG, 264.9 +/- 63.9 ms when observed by finger span and 229.4 +/- 41.8 ms when observed by the voice, which were all found to be significantly different (P < 0.05). When the automatic circuit breaker was used, the excessive stimulus time was 61.0 ms, which was 286.8 ms shorter than that measured from EMG onset when using the conventional EPT.

CONCLUSIONS

When the automatic circuit breaker was used, excessive stimulus time on the basis of EMG was attenuated on average by 286.8 ms.

Electroacupuncture reduces stress-induced expression of c-fos in the brain of the rat

We have previously shown that electroacupuncture (EA) at Shaohai and Neiguan (HT3-PC6) points significantly attenuated stress-induced peripheral responses, including increases in blood pressure, heart rate and plasma catecholamines. In this study, we examined the central effect of EA on the expression of c-fos, one of the immediate-early genes in the brain of rats subjected to immobilization stress. Immobilization stress (180 minutes) preferentially produced a significant increase in Fos-like immunoreactivity (FLI) in stress-relevant regions including the paraventricular hypothalamic nucleus (PVN), arcuate nucleus (ARN), supraoptic nucleus (SON), suprachiasmatic nucleus (SCN), medial amygdaloid nucleus (AMe), bed nucleus of the stria terminalis (BST), hippocampus, lateral septum (LS), nucleus accumbens, and the locus coeruleus (LC). EA (3 Hz, 0.2 ms rectangular pulses, 20 mA) at HT3-PC6 on the heart and pericardium channels for 30 minutes during stress, significantly attenuated stress-induced FLI in the parvocellular PVN, SON, SCN, AMe, LS and the LC. However, EA stimulations at HT3-PC6 had no effect on FLI in the magnocelluar PVN, ARN, BST or the hippocampus. EA stimulation at HT3-PC6 had a greater inhibitory effect on stress-induced FLI than that at TE5-LI11, the triple energizer and large intestine meridian, or non-acupoints. These results demonstrated that EA attenuated stress-induced c-fos expression in brain areas. These results suggest that decreased c-fos expression in hypothalamic and LC neurons, among stress-related areas, may reflect the integrative action of acupuncture in stress response.

Automatic stimulus breaker for electric dental pulp tester using pain response

The pulp test provides a means of examining the vitality of dental pulp using physical or chemical stimulation. During electrical pulp testing, an electrical current stimulates the intradental nerve, which may be painful and stressful to patients. The study involved measurement of the electromyogram (EMG) from the anterior belly of the digastric muscle, finger movement and voice response during electrical pulp testing. The excessive stimulus time from the onset time of response (EMG, voice and finger movement) to the end of the stimulation was obtained. The results indicated that the responses occurred in the order: EMG, finger and voice. Based on these results, an automatic stimulus shut-off circuit was developed using the above-mentioned responses to stimulus during electric pulp testing. Excessive stimulus time was reduced by prompt switching-off of the pulp tester output, 64 ms on average after the first detected response (EMG). Consequently, excessive stimulus times were reduced by 284 and 152 ms on average for the subject and examiner disconnection, respectively, using the developed automatic shut-off circuit. Therefore it was possible to minimise pain and stress by reducing excessive pulp stimulation.

Effect of electroacupuncture on bronchial asthma induced by ovalbumin in rats

INTRODUCTION

Asthma is a worldwide disabling chronic inflammatory airway disease characterized by an intense eosinophilic inflammatory infiltrate on bronchial mucous membranes. Among the complementary therapeutic approaches to asthma, acupuncture has been widely used.

OBJECTIVE

Here we used a rat pulmonary hypersensitivity experimental model that mimics human asthma in order to address whether electroacupuncture (EA) treatment could reduce the inflammatory process.

MATERIALS AND METHODS

Experimental animals were divided in four groups: control (C), immobilized (I), sham-acupuncture (SA), and acupuncture (A). All rats were sensitized with heat-solidified hen egg white implant. Using clinical acupuncture points, EA treatment began 2 days after antigen priming and was repeated on alternate days for 2 weeks. Subsequently, animals were challenged by inhalation with aggregated ovalbumin and sacrificed 24 hours later when blood samples, bronchoalveolar lavage (BAL), and lungs were collected.

RESULTS

Histopathologic analyses showed that peribronchial and perivascular inflammatory cell infiltrates were significantly lower in group A compared to groups SA and I (shown to be similar to group C). Furthermore, BAL total cell count and percentage of polymorphonuclears (as well as the differential counts of neutrophils and eosinophils) were significantly reduced in group A compared to group I. Corsticosterone plasma levels were similar in all groups.

CONCLUSIONS

Taken together these results show that EA efficiently diminishes the bronchial immune-mediated inflammation induced in rats and that this effect is dependent on the choice of specific acupoints.

Effects of electroacupuncture versus manual acupuncture on the human brain as measured by fMRI

The goal of this functional magnetic resonance imaging (fMRI) study was to compare the central effects of electroacupuncture at different frequencies with traditional Chinese manual acupuncture. Although not as time-tested as manual acupuncture, electroacupuncture does have the advantage of setting stimulation frequency and intensity objectively and quantifiably. Manual acupuncture, electroacupuncture at 2 Hz and 100 Hz, and tactile control stimulation were carried out at acupoint ST-36. Overall, electroacupuncture (particularly at low frequency) produced more widespread fMRI signal increase than manual acupuncture did, and all acupuncture stimulations produced more widespread responses than did our placebo-like tactile control stimulation. Acupuncture produced hemodynamic signal increase in the anterior insula, and decrease in limbic and paralimbic structures including the amygdala, anterior hippocampus, and the cortices of the subgenual and retrosplenial cingulate, ventromedial prefrontal cortex, frontal, and temporal poles, results not seen for tactile control stimulation. Only electroacupuncture produced significant signal increase in the anterior middle cingulate cortex, whereas 2-Hz electroacupuncture produced signal increase in the pontine raphe area. All forms of stimulation (acupuncture and control) produced signal increase in SII. These findings support a hypothesis that the limbic system is central to acupuncture effect regardless of specific acupuncture modality, although some differences do exist in the underlying neurobiologic mechanisms for these modalities, and may aid in optimizing their future usage in clinical applications.

Acupuncture-mediated inhibition of ethanol-induced dopamine release in the rat nucleus accumbens through the GABAB receptor

Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug abuse. However, there are still many unanswered questions about the basic mechanisms of acupuncture. Studies have shown that the GABA(B) receptor system may play a significant modulatory role in the mesolimbic system in drug abuse, including ethanol. The in vivo microdialysis study was designed to investigate the effect of acupuncture on acute ethanol-induced dopamine release in the nucleus accumbens and the potential role of the GABA(B) receptor system in acupuncture. Male Sprague-Dawley rats were administered with the highly selective GABA(B) antagonist SCH 50911 (3 mg/kg, i.p.) 1h prior to an intraperitoneal injection of ethanol (1 g/kg). Immediately after ethanol treatment, acupuncture was given at bilateral Shenmen (HT7) points for 1min. Acupuncture at the specific acupoint HT7, but not at control points (PC6 or tail) significantly decreased dopamine release in the nucleus accumbens. Inhibition of dopamine release by acupuncture was completely prevented by SCH 50911. These results suggest that stimulation of specific acupoints inhibits ethanol-induced dopamine release by modulating GABA(B) activity and imply that acupuncture may be effective in blocking the reinforcing effects of ethanol.

Suppression of IgE production and modulation of Th1/Th2 cell response by electroacupuncture in DNP-KLH immunized mice

Effects of electroacupuncture (EA) on Th1/Th2 cell response were investigated in BALB/c mice immunized intraperitoneally with 2,4-dinitrophenylated keyhole limpet protein (DNP-KLH). Successive electroacupuncture stimulation on the ST36 acupoint was performed just after immunization. Serum levels of antigen-specific IgE and total IgE were significantly decreased compared with non-acupunctured controls. Production of the Th2-specific cytokines IL-4 and IL-13 in the anti-CD3 mAb-activated splenocytes was significantly suppressed in ST36 electroacupunctured mice compared with non-acupunctured mice. These results imply that successive electroacupuncture on ST36 can decrease the serum level of antigen-specific IgE and total IgE by suppression of the Th2 lineage development.

Acupoint stimulation using bee venom attenuates formalin-induced pain behavior and spinal cord fos expression in rats

In two previous reports, we have demonstrated that injection of bee venom (BV) into an acupoint produces a significant antinociceptive and anti-inflammatory effect in both a mouse model of visceral nociception and a rat model of chronic arthritis. The present study was designed to evaluate the potential antinociceptive effect of BV pretreatment on formalin-induced pain behavior and it associated spinal cord Fos expression in rats. Adult Sprague-Dawley rats were injected with BV directly into the Zusanli (ST36) acupoint or into an arbitrary non-acupoint located on the back. BV pretreatment into the Zusanli acupoint significantly decreased paw-licking time in the late phase of the formalin test. In contrast, BV injected into a non-acupoint in the back region did not suppress the paw-licking time. In addition, BV pretreatment into the Zusanli acupoint markedly inhibited spinal cord Fos expression induced by formalin injection. These findings indicate that BV pretreatment into the Zusanli acupoint has an antinociceptive effect on formalin-induced pain behavior.

Effect of electroacupuncture on response to immobilization stress

Forced immobilization is a simple and effective stressor which produces large increases in heart rate (HR), blood pressure (BP), and plasma levels of norepinephrine (NE) and epinephrine (EPI). This study investigated the effects of electroacupuncture on BP, HR, and plasma catecholamine levels in rats challenged with immobilization stress. Male Sprague-Dawley rats received electroacupuncture (3 Hz, 0.2 ms pulses, 20 mA) for 30 min after start of immobilization stress (180 min). Needlepoints corresponded to Shaohai (HT3) and Neiguan (PC6) on the heart and pericardium channel. BP and HR were monitored with an indwelling carotid catheter, and blood samples were taken from the jugular vein. Blood (for HPLC determination of NE and EPI), mean BP, and HR were sampled at rest and during the immobilization stress at 15, 30, 60, 90, 120, 150, and 180 min. Electroacupuncture at HT3 and PC6 points but not at control points (TE5, LI11, and tail) significantly reduced the expected increases in BP, HR, and attenuated plasma levels of NE and EPI in response to 3 h of immobilization stress. Results provide strong evidence that electroacupuncture effectively reduces BP and HR increases and plasma catecholamine increases in rats challenged with immobilization stress.

Analgesic effect of the acupuncture using the method of quick insertion and withdrawal of the needle in rats

The method of quick insertion and withdrawal of the needle (QIW) in acupuncture is a technique of stimulation not retaining the needle in the acupuncture point. We examined the analgesic effects of five different types of QIW along with the changes of stimulation quantity, time, and depth, and then compared the analgesic effect of the most effective QIW to that of plain acupuncture (PA). When tail-flick latency values between the strongest QIW-I group and PA group were compared, there was no significant difference (analyzed by t-test). These results indicate that QIW technique has an analgesic effect similar to PA technique and that the conditions, which for the QIW-I was shown the most effective analgesia, are a duration of 5 s at intervals of 1 s and at the depth of 3 mm.

The difference between electroacupuncture only and electroacupuncture with manipulation on analgesia in rats

Plain acupuncture uses manipulation (rotation or varying the depth of insertion of the needle) to increase its effect. However, in commonly used electroacupunture (EA), variable manipulations have not been used. This study was performed to investigate the possibility of an increase in analgesic effect by adding manipulation to EA. The pain index used was the Tail-Flick latency (TFL) of the rat, which was lightly anesthetized with thiopental sodium (intraperitoneally). Four types of manipulation were used. Rotation and varying the depth of the needle (RN and VN) was employed using two different types of manipulation during each 20 min stimulation of EA. Each manipulation persisted for 1 min out of every 5 min (long - duration and long - interval: LDLI) or 12 s every 1 min (short - duration and short interval: SDSI). EA produced an increase in TFL; peak value was 49.7+/-12.2% of the pre - EA and occurred immediately after cessation of 20 min of EA stimulation. Performing RN or VN combined with EA also increased TFL more than just EA and a greater peak increase in TFL was observed with a SDSI - RN and SDSI - VN as compared to a LDLI - RN and LDLI - VN (77.5+/-13.8, 79.2+/-19.8 and 67.3+/-14.0%, 65.6+/-23.7% of the pre - EA, respectively). These results indicate that manipulation combined with EA produces a more potent antinociception than when only EA is applied.