Anatomical evidence of regional specific effects of acupuncture on gastric motor function in rats

Comparisons of different electrical stimulation modalities for treating visceral pain in a rodent model of irritable bowel syndrome

The purpose of this study was to investigate the effects of different electrical stimulation methods (bilateral electroacupuncture (BEA), unilateral EA (UEA), transcutaneous electrical acustimulation (TEA, stimulation via surface electrodes placed at acupoints), and sacral nerve stimulation (SNS)) on visceral pain in a rodent model of irritable bowel syndrome (IBS). Ten-day-old male and female pups were treated with 0.2 ml of 0.5% acetic acid (AA) solution. Visceral sensitivity was assessed using an electromyogram (EMG) in response to graded colorectal distension. In the first experiment, bilateral EA at ST36 acupoint was performed with different parameters in male rats to determine the best stimulation parameters. In the second experiment, male rats were randomly assigned into the Sham, BEA, UEA, TEA, and SNS groups to determine the best stimulation method. Lastly, the AA-treated female rats were randomly assigned into the BEA and sham groups to investigate a potential treatment difference between the sexes. Two distinct sets of stimulation parameters were used: Set 1 (100 Hz, 0.5 ms pulse width, 0.1 s ON, 0.4 s OFF, 0.4-3.0 mA current) and Set 2 (25 Hz, 0.5 ms pulse width, 2 s ON, 3 s OFF, 0.4-3.0 mA current).Results (1) The parameter set of 100Hz was found to be most effective in reducing visceral pain. (2) Both acute UEA and TEA effectively relieved visceral pain, whereas acute SNS did not exhibit such an effect. (3) Acute BEA improved visceral pain in both male and female rats.Conclusions These findings suggest that transcutaneous ST36 stimulation is as effective as direct ST36 stimulation and unilateral ST36 stimulation is comparable to bilateral stimulation. Development of a novel therapy using unilateral transcutaneous ST36 stimulation is warranted.

Autonomic and cytokine mechanisms of acute electroacupuncture in a rodent model of functional dyspepsia

BACKGROUND

Cytokines have been presumed to play an important role in the pathophysiology of functional dyspepsia (FD). Electroacupuncture (EA) has been used for FD treatment; however, its mechanisms remain largely unknown. This study aimed to (1) compare the plasma levels of cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-10, in "FD" rats with normal control rats; (2) investigate whether EA, using chronically implanted electrodes, could inhibit the release of these cytokines; and (3) explore the correlation of cytokine levels with plasma norepinephrine (NE) levels and gastric emptying (GE).

METHODS

A rodent model of FD was established via neonatal treatment with intragastric iodoacetamide. After 8 weeks, the rats were implanted with electrodes at acupoint ST36 for EA. The plasma levels of cytokines and NE were measured using enzyme-linked immunosorbent assay. We explored the correlations of cytokine levels with NE levels and GE.

KEY RESULTS

(i) "FD" rats demonstrated increased levels of TNF-α, IL-1β, and IL-6 (p < 0.05 each) compared with the control rats. (ii) EA significantly decreased the plasma levels of TNF-α, IL-1β, and IL-6 in "FD" rats (p < 0.05 each) compared with sham EA. (iii) The plasma levels of NE were positively correlated with those of IL-6 (r = 0.86, p < 0.05) and IL-1β (r = 0.81, p < 0.05), whereas NE levels and GE were negatively correlated with IL-10 levels (r = -0.870, p < 0.05 and r = -0.791, p < 0.05, respectively).

CONCLUSIONS

EA inhibits the release of proinflammatory cytokines probably via the suppression of sympathetic activity in "FD" rats.

Effect and mechanism of needleless transcutaneous neuromodulation on gastrointestinal function after pancreaticoduodenectomy

BACKGROUND

Gastrointestinal motility disorders tend to develop after pancreaticoduodenectomy (PD). The objectives of this study were: (1) to investigate the impact of needleless transcutaneous neuromodulation (TN) on the postoperative recuperation following pancreaticoduodenectomy (PD), and (2) to explore the underlying mechanisms by which TN facilitates the recovery of gastrointestinal function after PD.

METHODS

A total of 41 patients scheduled for PD were randomized into two groups: the TN group (n = 21) and the Sham-TN group (n = 20). TN was performed at acupoints ST-36 and PC-6 twice daily for 1 h from the postoperative day 1 (POD1) to day 7. Sham-TN was performed at non-acupoints. Subsequent assessments incorporated both heart rate variation and dynamic electrogastrography to quantify alterations in vagal activity (HF) and gastric pacing activity.

RESULTS

1)TN significantly decreased the duration of the first passage of flatus (p < 0.001) and defecation (p < 0.01) as well as the time required to resume diet (p < 0.001) when compared to sham-TN;2)Compared with sham-TN, TN increased the proportion of regular gastric pacing activity (p < 0.01);3) From POD1 to POD7, there was a discernible augmentation in HF induced by TN stimulation(p < 0.01);4) TN significantly decreased serum IL-6 levels from POD1 to POD7 (p < 0.001);5) TN was an independent predictor of shortened hospital stay(β = - 0.349, p = 0.035).

CONCLUSION

Needleless TN accelerates the recovery of gastrointestinal function and reduces the risk of delayed gastric emptying in patients after PD by enhancing vagal activity and controlling the inflammatory response.

Acceleration of postoperative recovery with brief intraoperative vagal nerve stimulation mediated via the autonomic mechanism

Introduction

Postoperative recovery is largely dependent on the restoration of gastrointestinal motility. The aim of this study was to investigate the effects and mechanisms of intraoperative vagus nerve stimulation (iVNS) on postoperative recovery from abdominal surgery in rats.

Methods

The Nissen fundoplication surgery was performed on two groups of rats: sham-iVNS group and iVNS group (VNS was performed during surgery). Animal's behavior, eating, drinking and feces' conditions were monitored at specific postoperative days. Gastric slow waves (GSWs) and electrocardiogram (ECG) were recorded; blood samples were collected for the assessment of inflammatory cytokines.

Results

(1) iVNS shortened initiate times to water and food intake (p = 0.004) and increased the number of fecal pellets (p < 0.05, vs. sham-iVNS) and the percentage of water content in fecal pellets (p < 0.05). (2) iVNS improved gastric pace-making activity at 6 h after surgery reflected as a higher percentage of normal slow waves (p = 0.015, vs. sham-iVNS). (3) iVNS suppressed inflammatory cytokines at 24 h after surgery compared to sham-iVNS (TNF-α: p = 0.001; IL-1β: p = 0.037; IL-6: p = 0.002). (4) iVNS increased vagal tone compared to sham-iVNS group at 6 h and 24 h after the surgery (p < 0.05). Increased vagal tone was correlated with a faster postoperative recovery to start water and food intake.

Conclusion

Brief iVNS accelerates postoperative recovery by ameliorating postoperative animal behaviors, improving gastrointestinal motility and inhibiting inflammatory cytokines mediated via the enhanced vagal tone.

A bibliometric analysis of 100 top-cited journal articles related to acupuncture regulation of the autonomic nervous system

Purpose

Research on the effects of acupuncture on autonomic function has been conducted for several decades, and a few notable studies have emerged in recent years. This study used bibliometric analysis to assess 100 top-cited articles to characterize the current status and research trends over the last three decades.

Methods

The 100 top-cited publications were identified from the Web of Science Core Collection database. The bibliometrix package in R was used for quantitative and qualitative analyses of the publication patterns and the country/region, institution, and author contributions. VOSviewer was used to construct networks based on co-citation analysis of the journals and the keyword co-occurrence.

Results

The 100 top-cited articles were identified with a total of 8,123 citations (range: 37-345). The majority of the articles came from the USA (n = 42), followed by Japan (n = 14) and mainland China (n = 13). Articles from the USA exhibited the largest number of citations (3,582 citations), followed by articles from Japan (1,189 citations), then articles from mainland China (755 citations). Neurosciences/Neurology was the most studied research area (n = 41). The Autonomic Neuroscience: Basic and Clinical published the largest number of papers (n = 14), while Brain Research received the largest number of citations (205 citations). Longhurst JC was the most productive author (10 publications), and Sato A was first among the cited authors (87 citations). The most frequently cited articles that focused on gastrointestinal, cardiovascular, or gynecologic responses to acupuncture regulation of the autonomic nervous system first appeared in the 1990s, peaked in the 2000s, then decreased after 2010. Publication of articles focused on the anti-inflammatory effects of acupuncture associated with autonomic function demonstrated an increasing trend over the last three decades.

Conclusion

From the initial studies focusing on the autonomic mechanism of visceral responses to acupuncture, researchers concentrated on exploring the autonomic mechanism of acupuncture in the control of systemic inflammation. Non-invasive electrical methods that activate somato-autonomic reflexes are current translational directions in clinical practice. Additional investigation of the underlying neuroanatomical basis of somato-autonomic reflexes also is needed.

Somatotopic organization of autonomic reflexes by acupuncture

Acupuncture has been practiced for more than 2000 years in China and now all over the world. One core idea behind this medical practice is that stimulation at specific body regions (acupoints) can distantly modulate organ physiology, but the underlying scientific basis has been long debated. Here, I summarize evidence supporting that long-distant acupuncture effects operate partly through somato-autonomic reflexes, leading to activation of sympathetic and/or parasympathetic pathways. I then discuss how the patterning of the somatosensory system along the rostro-caudal axis and the cutaneous-deep tissue axis might explain acupoint specificity and selectivity in driving specific autonomic pathways, particularly those modulating gastrointestinal motility and systemic inflammation.

Effects of Moxibustion on Stress-Induced Delayed Gastric Emptying via Somatoautonomic Reflex in Rats

Objective: Moxibustion (MOX) is used to treat a wide variety of disorders, including those with gastric symptoms. However, the exact mechanisms underlying the beneficial effects of MOX are unknown. The purpose of this study was to investigate if application of indirect MOX (iMOX) to ST 36 reduces restraint stress (RS)-induced alteration in gastric responses of conscious rats, and if a somatoautonomic reflex mediates gastric emptying (GE). Materials and Methods: One group of rats was fed solid food after 24 hours of fasting. Immediately after food ingestion. These rats were subjected to RS. Ninety minutes after feeding, the rats were euthanized, and their gastric contents were removed to calculate GE. iMOX had been performed at ST 36 bilaterally throughout the stress loading. To investigate if vagal-nerve activity was involved in mediating the stress-induced alterations of GE by iMOX, atropine was intraperitoneally administered to other rats just before initiating RS; bilateral truncal vagotomy had been performed on day 14 before GE measurement. Results: RS delayed GE significantly (42.9 ± 5.8%)in stressed rats, compared to nonstressed rats (68.7 ± 1.8%). iMOX at ST 36 reduced stress-induced inhibition of GE significantly (67.1 ± 2.4%). MOX-mediated reduction of GE disappeared upon atropine injection and vagotomy. Conclusions: RS-induced delayed GE may be ameliorated by iMOX at ST 36. Somatoautonomic, reflex-induced vagal-nerve activity helps mediate the stimulatory effects of iMOX on RS-induced delayed GE. As a complementary and alternative medicine, iMOX may also be advantageous for patients with gastric disorders, such as functional dyspepsia.

Acute Colonic Pseudo-Obstruction After Posterior Spinal Fusion: A Case Report and Literature Review

BACKGROUND

Acute colonic pseudo-obstruction (ACPO) or Ogilvie's syndrome occurs in 0.22%-7% of patients undergoing surgery, with a mortality of up to 46%. ACPO increased median hospital days versus control in spinal surgery (14 vs. 6 days; P < 0.001). If defined as postoperative ileus, the incidence was 7%-13.4%. Postoperative ileus is associated with 2.9 additional hospital days and an $80,000 increase in cost per patient. We present a case of ACPO in an adult patient undergoing spinal fusion for correction of scoliosis and review the available literature to outline clinical characteristics and surgical outcomes.

CASE DESCRIPTION

The patient was a 31-year-old woman with untreated advanced scoliosis with no history of neurologic issues. T2-L3 spinal instrumentation and fusion was completed. Plain abdominal radiography showed of dilated cecum 11 cm and the department of general surgery was consulted. Neostigmine administration was planned after conservative treatment failure after transfer to the intensive care unit. The patient was discharged home with no recurrence >60 days. Thirty cases were found in our literature review using PubMed and Embase databases and summarized.

CONCLUSIONS

Of 30 cases reviewed, only 3 cases of ACPO were specific to patients undergoing spinal fusion for scoliosis. According to the literature, 20% of patients had resolution with conservative treatment, 40% with neostigmine, and 30% with surgical intervention. Other noninvasive treatments may have similar efficacy in preventing complications leading to surgical invention. Sixty clinical trials and 9 systematic reviews were summarized with an updated management algorithm.

Neuromechanism of acupuncture regulating gastrointestinal motility

Acupuncture has been used in China for thousands of years and has become more widely accepted by doctors and patients around the world. A large number of clinical studies and animal experiments have confirmed that acupuncture has a benign adjustment effect on gastrointestinal (GI) movement; however, the mechanism of this effect is unclear, especially in terms of neural mechanisms, and there are still many areas that require further exploration. This article reviews the recent data on the neural mechanism of acupuncture on GI movements. We summarize the neural mechanism of acupuncture on GI movement from four aspects: acupuncture signal transmission, the sympathetic and parasympathetic nervous system, the enteric nervous system, and the central nervous system.

Effects of electroacupuncture on stress-induced gastric dysrhythmia and mechanisms involving autonomic and central nervous systems in functional dyspepsia

Electroacupuncture (EA) is widely used as an effective method to treat stress-related disorders. However, its mechanisms remain largely unknown. The aim of this study was to investigate the effects and mechanisms of EA on gastric slow wave (GSW) dysrhythmia and c-Fos expression in the nucleus of the solitary tract (NTS) induced by stress in a rodent model of functional dyspepsia (FD). Rats in the neonatal stage were treated using intragastric iodoacetamide. Eight weeks later, the rats were implanted with electrodes in the stomach for the measurement of GSW and electrodes into accupoints ST36 for EA. Autonomic functions were assessed by spectral analysis of heart rate variability. Rats were placed for 30 min in a cylindrical plastic tube for acute restraint stress. The involvement of a central afferent pathway was assessed by measuring c-Fos-immunoreactive cells in the NTS. 1) EA normalized restraint stress-induced impairment of GSW in FD rats. 2) EA significantly increased vagal activity (P = 0.002) and improved sympathovagal balance (P = 0.004) under stress in FD rats. 3) In FD rats under restraint stress, plasma norepinephrine concentration was increased substantially (P < 0.01), which was suppressed with EA. 4) The EA group showed increased c-Fos-positive cell counts in the NTS compared with the sham EA group (P < 0.05) in FD rats. Acute restraint stress induces gastric dysrhythmia in a rodent model of FD. EA at ST36 improves GSW under stress in FD rats mediated via the central and autonomic pathways, involving the NTS and vagal efferent pathway.

Electroacupuncture at ST36 modulates gastric motility via vagovagal and sympathetic reflexes in rats

BACKGROUND

Electroacupuncture (EA) at ST36 can significantly improve gastrointestinal symptoms, especially in promoting gastrointestinal motility. The automatic nervous system plays a main role in EA, but few studies exist on how vagovagal and sympathetic reflexes affect EA to regulate gastrointestinal motility.

AIM

To study the role of vagovagal and sympathetic reflexes in EA at ST36, as well as the associated receptor subtypes that are involved.

METHODS

Gastric motility was measured with a manometric balloon placed in the gastric antrum area in anesthetized animals. The peripheral nervous discharge was measured using a platinum electrode hooking the vagus or greater splanchnic nerve, and the central nervous discharge was measured with a glass microelectrode in the dorsal motor nucleus of the vagus (DMV). The effects and mechanisms of EA at ST36 were explored in male Sprague-Dawley rats which were divided in to a control group, vagotomy group, sympathectomy group, and microinjection group [including an artificial cerebrospinal fluid group, glutamate (L-Glu) group, and γ-aminobutyric acid (GABA) group] and in genetically modified male mice [β1β2 receptor-knockout (β1β2^-/-) mice, M2M3 receptor-knockout (M2M3^-/-) mice, and wild-type control mice].

RESULTS

EA at ST36 promoted gastric motility during 30-120 s. During EA, both vagus and sympathetic nerve discharges increased, with a much higher frequency of vagus nerve discharge than sympathetic discharge. The gastric motility mediated by EA at ST36 was interdicted by vagotomy. However, gastric motility mediated by EA at ST36 was increased during 0-120 s by sympathectomy, which eliminated the delay effect of EA during 0-30 s, but it was lower than the control group during 30-120 s. Using gene knockout mice and their wild-type controls to explore the receptor mechanisms, we found that EA at ST36 decreased gastric motility in M2/3^-/- mice, and promoted gastric motility in β1/2^-/- mice. Extracellular recordings showed that EA at ST36 increased spikes of the DMV. Microinjection of L-Glu into the DMV increased gastric motility, while EA at ST36 decreased gastric motility during 0-60 s, and promoted gastric motility during 60-120 s. Injection of GABA reduced or increased gastric motility, and reduced the promoting gastric motility effect of EA at ST36.

CONCLUSION

These data suggest that EA at ST36 modulates gastric motility via vagovagal and sympathetic reflexes mediated through M2/3 and β1/2 receptors, respectively. Sympathetic nerve activity mediated through β1/2 receptors is associated with an early delay in modulation of gastric motility by EA at ST36.

Ameliorating Effects of Electroacupuncture on Dysmotility, Inflammation, and Pain Mediated via the Autonomic Mechanism in a Rat Model of Postoperative Ileus

Background/Aims

Postoperative ileus increases healthcare costs and reduces the postoperative quality of life (QOL). The aim of this study is to investigate effects and mechanisms of electroacupuncture (EA) at ST36 and PC6 on gastrointestinal motility in rat model of postoperative ileus.

Methods

Laparotomy was performed in 24 rats (control [n = 8], sham-EA [n = 8], and EA [n = 8]) for the implantation of electrodes in the stomach and mid-jejunum for recording of gastric and small intestinal slow waves. Electrodes were placed in the chest skin for electrocardiogram (ECG). Intestinal manipulation (IM) was performed in Sham-EA and EA rats after surgical procedures. Small intestinal transit (SIT), gastric emptying (GE), postoperative pain, and plasma TNF-α were evaluated in all rats.

Results

(1) Compared with sham-EA, EA accelerated both SIT (P < 0.05) and GE (P < 0.05) and improved regularity of small intestinal slow waves. (2) Compared with the control rats (no IM), IM suppressed vagal activity and increased sympathovagal ratio assessed by the spectral analysis of heart rate variability from ECG, which were significantly prevented by EA. (3) EA significantly reduced pain score at 120 minutes (P < 0.05, vs 15 minutes) after the surgery, which was not seen with sham-EA. (4) Plasma TNF-α was increased by IM (P = 0.02) but suppressed by EA (P = 0.04) but not sham-EA.

Conclusion

The postoperative ileus induced by IM, EA at ST36 and PC6 exerts a prokinetic effect on SIT and GE, a regulatory effect on small intestinal slow waves and an analgesic effect on postoperative pain possibly mediated via the autonomic-cytokine mechanisms.

Acupuncture activates a direct pathway from the nucleus tractus solitarii to the rostral ventrolateral medulla

Our previous studies have shown that electroacupuncture (EA) at the Jianshi-Neiguan acupoints (P5-6, overlying the median nerve) attenuates sympathoexcitatory responses through its influence on neuronal activity in the rostral ventrolateral medulla (rVLM). The nucleus tractus solitarii (NTS) receives input from somatic nerve stimulation. Connections between the NTS and the rVLM during EA stimulation have not been investigated and thus were the focus of the present study. Seven to ten days after unilateral microinjection of a rhodamine-conjugated microsphere retrograde tracer (100 nl) into the rVLM, rats were subjected to EA or sham-EA without electrical stimulation. EA was performed for 30 min at the P5-6 acupoints bilaterally. Perikarya containing the microsphere tracer were found in the NTS of both groups. Compared to controls (needle placement without electrical stimulation, n = 7), c-Fos immunoreactivity and neurons double-labeled with c-Fos, an immediate early gene, and the tracer were significantly increased in the NTS of EA-treated rats (all P < 0.05; n = 8), particularly, in the medial and lateral subdivisions of NTS at subpostremal and obex levels. These results suggest that EA at the P5-6 acupoints activates NTS neurons. Furthermore, EA-activated NTS neurons directly project to the rVLM and likely influence the rVLM activity.

Laserpuncture Increases Serum Concentration of Insulin-Like Growth Factor-1 in Adolescent Rats

Objective: Previous studies have demonstrated that laserpuncture has a positive effect on longitudinal bone growth within varying parameters. The current authors hypothesized that laserpuncture affects serum concentration of insulinlike growth factor 1 (IGF-1), a growth factor that influences growth plates, and ghrelin, a growth hormone (GH) secretagogue. The goal of this research was to investigate if laserpuncture could increase serum concentrations of IGF-1 and ghrelin in adolescent rats. Materials and Methods: This was an experimental study with a post-test only and a controlled group design. The study was performed in a laboratory on 40 male Wistar rats, age ±3 weeks and weighing >40 g. The rats were divided randomly into 2 groups, A and B, each receiving laserpuncture for 10 days and 15 days, respectively. There were 4 subgroups in each group: control (C); GV 20; ST 36; and GV 20 + ST 36. The rats were stimulated by laserpuncture with a KX Laser GX-2000B (Kangxing), a semiconductor-based low-level laser therapy (LLLT) device emitting a cold red laser (635-680 nm/5 mW) for 60 seconds (0.3 J/cm²) The length of each rat's lower limb was measured using a caliper; IGF-1 and ghrelin concentrations were assessed using enzyme-linked immunosorbent assays. Results: A marked increase in IGF-1 concentration was observed in the ST 36 and GV 20 + ST 36 subgroups after 15 days, compared to the C subgroup (P = 0.001 and P = 0.002, respectively). The GV 20 subgroup had a lower IGF-1 concentration than the C subgroup (P = 0.06) at both 10 and 15 days. Laserpuncture did not influence ghrelin concentrations significantly, compared to the C subgroups. Conclusions: Laserpuncture administered to both the ST 36 and GV 20 + ST 36 subgroups with a power density of 0.3 J/cm² increased serum concentrations of IGF-1 in adolescent rats.

Electroacupuncture via chronically implanted electrodes improves gastric dysmotility mediated by autonomic-cholinergic mechanisms in a rodent model of functional dyspepsia

BACKGROUND

Electroacupuncture (EA) has been shown to be effective in reducing symptoms in patients with functional dyspepsia (FD). However, its mechanisms remain largely unknown. The aim of this study was to investigate mechanisms of the prokinetic effects of EA in a rodent model of FD.

METHODS

A FD model was established by neonatal treatment of iodoacetamide (IA). Eight weeks later, the rats were implanted with electrodes in the stomach for the measurement of gastric slow waves (GSW) and electrodes into acupoints ST36 for EA. Autonomic functions were assessed by the spectral analysis of heart rate variability.

KEY RESULTS

(i) The IA-treated rats ("FD" rats) showed increased dysrhythmia in both fasting and fed states (P < .01) as well as during rectal distention (P < .02). EA reduced the percentage of dysrhythmia (P < .05 for both fasting and fed) and normalized RD-induced impairment in GSW in "FD" rats. Atropine blocked the effect of EA on GSW. (ii) "FD" rats showed delayed gastric emptying (P = .001 vs control) that was accelerated with EA (P = .01, vs sham-EA). (iii) "FD" rats showed increased plasma norepinephrine (P = .006, vs control) that was suppressed with EA (P = .003) and reduced vagal activity that was improved with EA.

CONCLUSIONS AND INFERENCES

Gastric motility (GSW and GE) is impaired in rats treated with IA, possibly attributed to impaired autonomic functions. EA improves GSW and accelerates GE mediated via the autonomic and cholinergic mechanisms.

Acupuncture at heterotopic acupoints facilitates distal colonic motility via activating M3 receptors and somatic afferent C-fibers in normal, constipated, or diarrhoeic rats

BACKGROUND

Previous studies have demonstrated the efficacy of somatic stimulation for patients with gastrointestinal motility disorders. However, little effort has been made to investigate the effects of acupuncture on colonic motility, particularly in pathological conditions. The precise mechanism employed in the regulation of acupuncture on colonic motility still remains unclear.

METHODS

We assessed the effect of acupuncture at heterotopic acupoints on distal colonic motility using a warm-water-filled manometric balloon inserted 5-6 cm into the rectum of anesthetized normal rats or rats with diarrhea or constipation. Choline chloride, 4-DAMP, cobra venom and capsaicin were separately applied to investigate the role of M3 receptors in the regulation of distal colonic motility by acupuncture at heterotopic acupoints, and whether Aδ- and/or C-fibers are required for triggering distal colonic motility by acupuncture.

KEY RESULTS

Acupuncture at heterotopic acupoints increased distal colonic motility not only in normal rats but also in rats with constipation or diarrhea. M3 receptors play an important role in the facilitation of distal colonic motility triggered by acupuncture at heterotopic acupoints. Afferent nerve Aδ- and C-fibers mediate the transduction of the acupuncture signal and C-fibers are essential for enhancing the effect of acupuncture at the heterotopic acupoint on distal colonic motility.

CONCLUSIONS & INFERENCES

Our results reveal that acupuncture at heterotopic acupoints increases distal colonic motility regardless of normal or pathological conditions via predominately activating C-fibers of somatic afferent nerve and M3 receptors.

The effect and mechanism of electroacupuncture at LI11 and ST37 on constipation in a rat model

Background

Electroacupuncture (EA) is used clinically for the treatment of constipation. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in colonic motility; however it is unknown whether alterations in colonic 5-HT are associated with EA. In this study, the effect and mechanism of EA at acupuncture points LI11 and ST37 were examined using a cold saline-induced rat model of constipation.

Methods

A rat constipation model was induced by cold saline gavage in 24 Sprague-Dawley rats. A further six rats were included as a Control group. The constipated rats were divided into four groups (n=6 each): a Constipation group that remained untreated; a Constipation+LI11 group that received EA at LI11; a Constipation+ST37 groups that received EA at ST37; and a Constipation+LI11+ST37 group that received EA at both LI11 and ST37. After EA treatment, faecal water content, defaecation frequency, and gastrointestinal (GI) transit were measured, as well as the expression of tryptophan hydroxylase (TPH) in colonic tissues (by Western blot analysis) and 5-HT in both faeces and colonic tissues (by ELISA).

Results

All three EA-treated groups demonstrated significant improvements in faecal water content, defaecation frequency and GI transit (p<0.05). In addition, TPH and 5-HT expression were both increased by EA at LI11 and/or ST37 (p<0.05). There were no significant differences between the three EA groups for any outcomes.

Conclusions

EA at LI11 and/or ST37 had a positive effect on objective markers of constipation in a rat model. In addition, EA increased 5-HT and TPH in the colonic tissues.

(1) H NMR Metabolic Profiling of Biofluids from Rats with Gastric Mucosal Lesion and Electroacupuncture Treatment

Gastric mucosal lesion (GML) is a common gastrointestinal disorder with multiple pathogenic mechanisms in clinical practice. In traditional Chinese medicine (TCM), electroacupuncture (EA) treatment has been proven as an effective therapy for GML, although the underlying healing mechanism is not yet clear. Here, we used proton nuclear magnetic resonance- (¹H NMR-) based metabolomic method to investigate the metabolic perturbation induced by GML and the therapeutic effect of EA treatment on stomach meridian (SM) acupoints. Clear metabolic differences were observed between GML and control groups, and related metabolic pathways were discussed by means of online metabolic network analysis toolbox. By comparing the endogenous metabolites from GML and GML-SM groups, the disturbed pathways were partly recovered towards healthy state via EA treated on SM acupoints. Further comparison of the metabolic variations induced by EA stimulated on SM and the control gallbladder meridian (GM) acupoints showed a quite similar metabolite composition except for increased phenylacetylglycine, 3,4-dihydroxymandelate, and meta-hydroxyphenylacetate and decreased N-methylnicotinamide in urine from rats with EA treated on SM acupoints. The current study showed the potential application of metabolomics in providing further insight into the molecular mechanism of acupuncture.

Effect of manual acupuncture on bowel motility in normal kunming mouse

OBJECTIVE

To observe the effects of acupuncture on motility of jejunum and distal colon at different acupoints on normal Kunming mice.

METHODS

The jejunal and colorectal motor activity of forty Kunming mice were recorded by the intra-intestinal capsule. The capsules contained with distilled water were placed into the cavities of jejunum and distal colon. The changes of bowel were compared with the background activity recorded before any stimulation. The chosen acupoints were as follows: Zusanli (ST 36) on the lower legs, Tianshu (ST 25) on the mid-lower abdomen.

RESULTS

Manual acupuncture (MA) at Zusanli (ST 36) significantly promoted the motility of jejunum and distal colon (manifested as increased change rate of average amplitude and increased change rate of mean area under the contractile curve) of normal Kunming mice (P < 0.01). MA at Tianshu (ST 25) significantly inhibited the motility of jejunum (manifested as decreased change rate of average amplitude, decreased change rate of mean area under the contractile curve, and the reduced frequency) of normal Kunming mice (P < 0.01), while significantly increased the distal colonic motility (manifested as increased amplitude and increased mean area under the contractile curve) of normal Kunming mice (P < 0.01).

CONCLUSION

MA at specific acupoints [Zusanli (ST 36), Tianshu (ST 25)] has different effects on the motility of jejunum and distal colon, which might involve the segmental innervations of the related nerve.

Complementary and alternative medicine for gastroparesis

Complementary and alternative medicine is of great interest to patients with gastrointestinal disorders and some will choose to ask their health care providers about those therapies for which some scientific evidence exists. This review focuses on those therapies most commonly used by patients, namely acupuncture/electroacupuncture and various herbal formulations that have been the focus of clinical and laboratory investigation. A discussion of their possible mechanisms of action and the results of clinical studies are summarized.

Ameliorating effects of auricular electroacupuncture on rectal distention-induced gastric dysrhythmias in rats

Gastric slow waves (GSW) are known to regulate gastric motility and are impaired with rectal distention (RD). Electroacupuncture (EA) at body acupoints, such as ST 36, has been shown to improve gastric dysrhythmias; however, little is known about the possible effects of auricular electroacupuncture (AEA) on GSW. To study effects and possible mechanisms of AEA on RD-induced gastric dysrhythmias in rats, ten male Sprague-Dawley (SD) rats implanted with gastric serosal electrodes were studied in two different experiments in fed state. Four sessions were performed in experiment 1 as follows: control (RD, no stimulation), RD+AEA, RD+EA at body points and RD+sham AEA. Two sessions were included in experiment 2 to study mechanisms of AEA: RD + atropine and RD + atropine + AEA. It was found that 1) RD significantly decreased the percentage of normal GSW from 89.8 ± 3.5% to 76.0 ± 3.3% (P<0.05); 2) AEA increased the percentage of normal GSW during RD to 94.0 ± 2.1% (P<0.05 vs. RD) via a reduction in the percentages of tachygastria and arrhythmia (P<0.05 vs. RD); 3) atropine blocked the ameliorating effect of AEA on RD-induced gastric dysrhythmias. Our results demonstrated that RD induces gastric dysrhythmias in fed state in rats. AEA improves RD-induced gastric dysrhythmias via the vagal pathway. AEA may have a therapeutic potential in treating gastric dysrhythmias.

Electroacupuncture at Zusanli (ST36) promotes gastric emptying and mucosal blood flow during oral resuscitation of scalded rats with a pyruvate-enriched ORS

AIM

The aim of this study was to investigate the effect of electroacupuncture at ST36 (EA ST36) on gastric emptying and mucosal blood flow during intragastric resuscitation with pyruvate-enriched oral rehydration solution (Pyr-ORS) in scalded rats.

METHODS

The rats were subjected to a 35% total body surface area (TBSA) of scald injury and randomly divided into five groups (N=24) and two subgroups (n=12) in each group. The Pyr-ORS was delivered intragastrically according to the Parkland formula immediately after scalding at a dose of 1 mL kg(-1) %TBSA(-1) in 1 h. In these animals, the bilateral Zusanli points (ST36) were electroacupunctured at a constant voltage (2 mA and 2-100 HZ) for 0.5 h immediately after intragastric resuscitation. At 2 and 4 h after scalding, the gastric emptying rate (GER) and gastric mucosal blood flow (GMBF) were determined, and the motilin levels of the plasma and gastric tissues were also analyzed at two time points, respectively.

RESULTS

GER and GMBF were markedly decreased in groups with scalding and resuscitation, compared with the sham groups at two time points (P<0.05), but they were greatly improved in groups byEAST36 at 2 and 4 h after sustaining scald injuries (P<0.05). Bilateral vagotomy further aggravated the reduction of GER and GMBF in scalded rats. EA after gastric vagotomy failed to raise GER and GMBF. Neither EA nor vagotomy had effects on the reduced motilin levels of plasma and gastric tissues in animals after scalding.

CONCLUSION

EA ST36 has a significant effect on improving gastric emptying and mucosal ischemia in the oral resuscitation of burn injury, possibly through the activation of a cholinergic nerve-dependent mechanism. In addition, EA ST36 showed no effects on motilin levels, but requires further investigations.

Electroacupuncture at ST36 accelerates the recovery of gastrointestinal motility after colorectal surgery: a randomised controlled trial

OBJECTIVES

To evaluate whether electroacupuncture (EA) at ST36 can accelerate the recovery of gastrointestinal motility after colorectal surgery.

METHODS

Forty patients of American Society of Anesthesiologists physical status II and III undergoing elective open resection of malignant colorectal tumours were included in this study. Using a sealed envelope method, the patients were randomly divided into two groups either receiving EA (EA group) or sham EA (SEA group). Data regarding the recovery of bowel function (times to the first bowel sounds, passage of flatus and defaecation) were collected and analysed.

RESULTS

In the EA group, the time intervals from surgery to the first bowel movement and passage of flatus were shorter than in the SEA group (13±10 h vs 19±13 h, p<0.05 and 23±14 h vs 32±18 h, p<0.05, respectively). There was no significant difference between the groups regarding the time to first defaecation (68±45 h vs 72±53 h, p>0.05).

CONCLUSIONS

EA at ST36 accelerates the recovery of gastrointestinal motility after colorectal surgery.

TRIAL REGISTRATION

JJ22011-15.

Electroacupuncture improves burn-induced impairment in gastric motility mediated via the vagal mechanism in rats

BACKGROUND

Delayed gastric emptying (GE) is common in patients with severe burns. This study was designed to investigate effects and mechanisms of electroacupuncture (EA) on gastric motility in rats with burns.

METHODS

Male rats (intact and vagotomized) were implanted with gastric electrodes, chest and abdominal wall electrodes for investigating the effects of EA at ST-36 (stomach-36 or Zusanli) on GE, gastric slow waves, autonomic functions, and plasma interleukin 6 (IL-6) 6 and 24 h post severe burns.

KEY RESULTS

(i) Burn delayed GE (P < 0.001). Electroacupuncture improved GE 6 and 24 h post burn (P < 0.001). Vagotomy blocked the EA effect on GE. (ii) Electroacupuncture improved burn-induced gastric dysrhythmia. The percentage of normal slow waves was increased with EA 6 and 24 h post burn (P = 0.02). (iii) Electroacupuncture increased vagal activity assessed by the spectral analysis of heart rate variability (HRV). The high-frequency component reflecting vagal component was increased with EA 6 (P = 0.004) and 24 h post burn (P = 0.03, vs sham-EA). (iv) Electroacupuncture attenuated burn-induced increase in plasma IL-6 at both 6 (P = 0.03) and 24 h post burn (P = 0.003).

CONCLUSIONS & INFERENCES

Electroacupuncture at ST-36 improves gastric dysrhythmia and accelerates GE in rats with burns. The improvement seems to be mediated via the vagal pathway involving the inflammatory cytokine IL-6.

Acupuncture point specificity

Acupuncture, as a modality treatment, has gained increasing popularity and acceptance between public and health-care professionals worldwide. Recently, there has been intensive debate about the efficacy of acupuncture therapy due to the conflicting outcome of clinical trials. Acupoint specificity was regarded as one of the core scientific issues with respect to acupuncture practice at the Society for Acupuncture Research international symposium held in 2007. In this chapter, we reviewed the recent development in basic science and clinical studies on the role of acupoint specificity. The evidence cumulated from brain imaging and many biological studies showed that the point specificity in acupuncture does exist, although acupoint specificity-related issues such as sham acupoint and placebo phenomenon need to be seriously considered. How to optimize the efficacy of acupoint and minimize the impact of sham acupuncture is an urgent issue faced by acupuncture community, and more studies are warranted on the subjects.

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.

The neural pathway of reflex regulation of electroacupuncture at orofacial acupoints on gastric functions in rats

Acupuncture has a reflex regulation in gastrointestinal functions, which is characterized with segment. In the present study, the neural pathway of electroacupuncture (EA) at orofacial acupoints (ST2) on gastric myoelectric activity (GMA) in rats was investigated. The results indicated that EA at ST2 facilitated spike bursts of GMA, which is similar to EA at limbs and opposite to EA at abdomen. The excitatory effect was abolished by the transaction of infraorbital nerves, dorsal vagal complex lesion, and vagotomy, respectively. In addition, microinjection of L-glutamate into the nucleus of the solitary tract (NTS) attenuated the excitatory effect. All these data suggest that the dorsal vagal complex is involved in the reflex regulation of EA at orofacial acupoints on gastric functions and NTS-dorsal motor nucleus of the vagus (DMV) inhibitory connections may be essential for it.

Effect of auricular acupuncture on gastrointestinal motility and its relationship with vagal activity

BACKGROUND

Vagus nerve stimulation is capable of regulating autonomic nerve function. In Traditional Chinese Medicine, the effect of auricular acupuncture (AA) is mediated by the vagus. This study was designed to investigate the effect of AA on gastrointestinal (GI) motility and the relationship of this effect with the vagus nerve.

METHODS

50 rats were divided into five groups for observation of the effects of different types of acupuncture and influencing factors: control, AA, somatic acupuncture (SA), atropine and atropine+AA. The acupuncture points used for AA were ST (Stomach) and SI (Small intestine), while the acupuncture point used for SA was ST36. Electroacupuncture was performed for 15 min. A model of reduced GI motility was established using ethanol, and GI transit rate was used to measure GI motility. Heart rate variability (HRV) and the effect of atropine administration were investigated to study the relationship between AA and vagal activity.

RESULTS

The GI transit rate increased in both the AA and SA groups compared with control, and no significant difference was found between their effects. In addition, after atropine administration, AA was found to be ineffective in influencing the GI transit rate. In the HRV analysis, no significant differences were found in the absolute low frequency normalised units, high frequency normalised units or the low frequency/high frequency component ratio in the AA or SA groups compared with control. After administration of atropine AA still had no effect on HRV.

CONCLUSIONS

The function of AA in improving GI motility is similar to that of SA, and this effect can be blocked by the presence of atropine, indicating that this effect is regulated by the vagus. However, HRV did not reflect the acupuncture-induced changes in vagal nerve function.

Acupuncture-stimulated activation of sensory neurons

Acupuncture is one of the key therapeutics in clinical oriental medicine, and recent studies using experimental animals have begun to provide the pathophysiological basis for the efficacy of acupuncture. Here, we investigated neuronal responses in rodent models given acupuncture stimulation. In both mice and rats, acupuncture stimulation at zusanli (ST36) generated an increased expression of axonal growth-associated protein (GAP-43) in the sensory neurons of the dorsal root ganglion (DRG). Electroacupuncture stimulation at ST36 in rats induced GAP-43 mRNA and protein expression in DRG neurons at the levels of lumbar 4 and 5. Stimulation on a non-acupuncture site as a sham control induced GAP-43 expression as well, but the induction level was lower than it was with acupuncture. We further found that acupuncture stimulation upregulated phospho-Erk1/2 signals in DRG neurons. Electroacupuncture stimulation induced c-Fos expression in the neurons of the dorsal motor nucleus of the vagus nerve (DMV), which was identified by retrograde tracing. These data suggest that acupuncture stimulation may generate physiological effects on the autonomic nervous system via the activation of a somatosensory pathway.

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.

Electroacupuncture improves rectal distension-induced delay in solid gastric emptying in dogs

The aim of this study was to investigate the effects and mechanisms of electroacupuncture (EA) on rectal distension (RD)-induced delay in solid gastric emptying in dogs. Gastric emptying of solids was assessed in 12 dogs chronically implanted with a duodenal cannula by collecting samples at different time points from the cannula and measuring the dried weights of the samples. Bethanechol and atropine were used to qualitatively validate the method. In separate experiments, gastric emptying of solids was measured in a number of sessions: control, RD, RD + sham-EA, RD + EA of 6 mA, RD + EA of 3 mA, and RD + EA + naloxone. The method of gastric emptying by collecting and drying gastric chyme from the duodenal cannula was found to be accurate and reliable. Using the method, we found gastric emptying to be accelerated with bethanechol (70.01 ± 8.10% vs. 82.61 ± 4.15%, P = 0.04, vs. control) and delayed with atropine (4.31 ± 1.57%, P < 0.001, vs. control). RD substantially and significantly delayed gastric emptying. EA, but not sham-EA, attenuated delayed gastric emptying induced by RD (sham-EA: 48.79 ± 9.47% vs. EA: 74.28 ± 5.96%, P < 0.01). The effect was more potent with EA of 6 mA than EA of 3 mA and blocked by naloxone. EA is able to attenuate RD-induced delay in gastric emptying of solids, and this ameliorating effect may be mediated via the opioid pathway. EA may have a therapeutic potential for treating delayed gastric emptying attributed to lower gut distension.

Effects and mechanisms of electroacupuncture on glucagon-induced small intestinal hypomotility in dogs

BACKGROUND

Little is known on the effect of electroacupuncture (EA) (Br Med J, 2, 1976, 1225) on intestinal motility. The aim of this study was to investigate effects and mechanisms of EA on small intestinal contractions, transit, and slow waves in dogs.

METHODS

Six dogs were equipped with two intestinal cannulas for the measurement of small intestinal contractions and transit. Glucagon was used to induce postprandial intestinal hypomotility. Each dog was studied in five randomized sessions: Control, glucagon, glucagon + EA, glucagon + EA + naloxone, and glucagon + EA + atropine.

KEY RESULTS

1 In the fasting state, EA induced intestinal contractions during motor quiescence (contractile index or CI: 4.4 ± 0.8 VS 8.3 ± 0.7, P < 0.05). 2 In the fed state, EA improved glucagon-induced intestinal hypomotility (CI: 3.8 ± 0.4 VS 6.1 ± 0.6, P < 0.05). 3 Electroacupuncture accelerated intestinal transit delayed by glucagon (67.9 ± 4.3 VS 40.2 ± 5.0 min, P < 0.05). 4 There was a negative correlation between the CI and the total transit time (R(2) = 0.59, P < 0.05). 5 The excitatory effect of EA was blocked by naloxone and partially blocked by atropine. 6 The percentage of normal slow waves was reduced with glucagon (70 ± 2%VS 98 ± 1% at baseline, P = 0.0015). Electroacupuncture normalized impaired slow waves and the effect was blocked by naloxone.

CONCLUSIONS & INFERENCES

Electroacupuncture enhances intestinal contractions during Phase I of the migrating motor complex and glucagon-induced hypomotility in the fed state, and accelerates intestinal transit via the opioid and cholinergic pathways in dogs. Electroacupuncture may have a therapeutic potential for intestinal hypomotility.

Paradoxes in acupuncture research: strategies for moving forward

In November 2007, the Society for Acupuncture Research (SAR) held an international symposium to mark the 10th anniversary of the 1997 NIH Consensus Development Conference on Acupuncture. The symposium presentations revealed the considerable maturation of the field of acupuncture research, yet two provocative paradoxes emerged. First, a number of well-designed clinical trials have reported that true acupuncture is superior to usual care, but does not significantly outperform sham acupuncture, findings apparently at odds with traditional theories regarding acupuncture point specificity. Second, although many studies using animal and human experimental models have reported physiological effects that vary as a function of needling parameters (e.g., mode of stimulation) the extent to which these parameters influence therapeutic outcomes in clinical trials is unclear. This White Paper, collaboratively written by the SAR Board of Directors, identifies gaps in knowledge underlying the paradoxes and proposes strategies for their resolution through translational research. We recommend that acupuncture treatments should be studied (1) “top down” as multi-component “whole-system” interventions and (2) “bottom up” as mechanistic studies that focus on understanding how individual treatment components interact and translate into clinical and physiological outcomes. Such a strategy, incorporating considerations of efficacy, effectiveness and qualitative measures, will strengthen the evidence base for such complex interventions as acupuncture.

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.

Gastrointestinal motility disorders and acupuncture

During the last decades, numerous studies have been performed to investigate the effects and mechanisms of acupuncture or electroacupuncture (EA) on gastrointestinal motility and patients with functional gastrointestinal diseases. A PubMed search was performed on this topic and all available studies published in English have been reviewed and evaluated. This review is organized based on the gastrointestinal organ (from the esophagus to the colon), components of gastrointestinal motility and the functional diseases related to specific motility disorders. It was found that the effects of acupuncture or EA on gastrointestinal motility were fairly consistent and the major acupuncture points used in these studies were ST36 and PC6. Gastric motility has been mostly studied, whereas much less information is available on the effect of EA on small and large intestinal motility or related disorders. A number of clinical studies have been published, investigating the therapeutic effects of EA on a number of functional gastrointestinal diseases, such as gastroesophageal reflux, functional dyspepsia and irritable bowel syndrome. However, the findings of these clinical studies were inconclusive. In summary, acupuncture or EA is able to alter gastrointestinal motility functions and improve gastrointestinal motility disorders. However, more studies are needed to establish the therapeutic roles of EA in treating functional gastrointestinal diseases.

Ameliorating effects and mechanisms of electroacupuncture on gastric dysrhythmia, delayed emptying, and impaired accommodation in diabetic rats

The aim of this study was to investigate the effects and mechanisms of electroacupuncture (EA) on gastric accommodation, gastric dysrhythmia, and gastric emptying (GE) in streptozotocin (STZ)-induced diabetic rats. Five experiments were performed in five groups of STZ-induced diabetic rats to study the effects of EA at ST-36 (Zusanli) on gastric slow-wave dysrhythmia, delayed GE and intestinal transit, impaired gastric accommodation, and the mechanisms of EA involving the autonomic and opioidergic pathways. We found the following: 1) EA improved gastric dysrhythmia in the diabetic rats. The normal percentage of slow waves was 55.4 +/- 2.9% at baseline and significantly increased to 69.2 +/- 2.2% with EA (P = 0.01); this effect was blocked by naloxone. 2) EA resulted in a 21.4% increase in GE and 18.2% increase in small intestinal transit in the diabetic rats. 3) EA restored diabetes-induced impairment in gastric accommodation. Gastric accommodation was 0.98 +/- 0.13 ml with sham EA and significantly increased to 1.21 +/- 0.15 ml with EA (P = 0.01), and this effect was blocked by naloxone. 4) EA increased vagal activity assessed by the spectral analysis of the heart rate variability. We concluded that EA at ST-36 improves gastric dysrhythmia, delayed GE and intestinal transit, and impaired accommodation in STZ-induced diabetic rats, and the improvement seems to be mainly mediated via the vagal pathway. EA may have a promising therapeutic potential for diabetic gastroparesis.

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.

Effects of electroacupuncture on gastric motility and heart rate variability in conscious rats

To clarify the mechanism of site-specific effects of acupuncture on gastric motor function, we studied the simultaneous recording of gastric motility and electrocardiogram (ECG) for heart rate variability (HRV) analysis in conscious rats. Gastric motility and ECG were recorded before, during and after electroacupuncture (EA) at ST-36 (hind limb) or ST-25 (abdomen). EA at ST-36 significantly increased gastric motility and decreased the ratio of low frequency (LF)/high frequency (HF) of the HRV analysis. In contrast, EA at ST-25 significantly inhibited gastric motility and increased LF/HF ratio. There was a significant correlation observed between the changes of gastric motility and LF/HF ratio in response to EA. It is suggested that the stimulatory effect of EA at ST-36 on gastric motility is associated with its stimulatory effect on vagal activity. The inhibitory effect of EA at ST-25 on gastric motility is associated with its stimulatory effect on the sympathetic nerve activity.