Somato stimulation and acupuncture therapy.

Acupuncture is an oldest somato stimulus medical technique. As the most representative peripheral nerve stimulation therapy, it has a complete system of theory and application and is applicable to a large population. This paper expounds the bionic origins of acupuncture and analyzes the physiological mechanism by which acupuncture works. For living creatures, functionally sound viscera and effective endurance of pain are essential for survival. This paper discusses the way in which acupuncture increases the pain threshold of living creatures and the underlying mechanism from the perspective of bionics. Acupuncture can also help to adjust visceral functions and works most effectively in facilitating the process of digestion and restraining visceral pain. This paper makes an in-depth overview of peripheral nerve stimulation therapy represented by acupuncture. We look forward to the revival of acupuncture, a long-standing somato stimulus medicine, in the modern medical systems.

Effects of electroacupuncture on expression of c-fos protein and N-methyl-D-aspartate receptor 1 in the rostral ventromedial medulla of rats with chronic visceral hyperalgesia.

OBJECTIVE: Acupuncture has been clinically proved to be effective in treating abdominal pain in patients with irritable bowel syndrome (IBS). However, its neurobiological mechanism remains largely unexplored. The aim of this study was to investigate the effect of electroacupuncture (EA) in relieving chronic visceral hyperalgesia and the possible involvement of N-methyl-D-aspartate receptor 1 (NR1) in rostral ventromedial medulla (RVM) of the brain in an IBS rat model. METHODS: To establish the IBS rat model, male Sprague-Dawley neonatal rats received colon mechanical irritation on a daily basis from the 9th to the 22nd day after their birth. After a resting period of another two to four weeks, behavioral tests of pain threshold pressure (PTP) and abdominal withdrawal reflex (AWR) responding to colorectal distention (CRD) stimuli were conducted to judge the colorectal sensitive situation. Then administration of EA at acupoints of Zusanli (ST36) and Shangjuxu (ST37) bilaterally in the hind limbs was repeated four times every other day, while sham-EA was done by inserting needles at similar acupoints without electrical stimulation. Immunohistochemical method was used to display the expression of proto-oncogene protein c-fos and NR1 in RVM of rats. RESULTS: The results demonstrated that the PTP values and AWR scores, in response to the CRD stimuli, significantly decreased and increased, respectively (P<0.01, P<0.01), while the number of immunoreactive neurons of c-fos protein and NR1 significantly increased in nucleus reticularis gigantocellularis (Gi), nucleus lateralis paragigantocellularis (LPGi), nucleus reticularis gigantocellularis pars alpha (GiA) and nucleus raphe magnus (NRM) of RVM in IBS model rats compared with the normal rats (P<0.05). After EA treatment, PTP values and AWR scores significantly increased and decreased, respectively (P<0.01, P<0.05); the number of immunoreactive neurons of c-fos and NR1 significantly decreased respectively in Gi, LPGi and GiA and in Gi, LPGi, GiA and NRM (P<0.05). No such effects on PTP values, AWR scores and the number of immunoreactive neurons of c-fos and NR1 were observed after sham-EA treatment. CONCLUSION: These data provide the evidence that EA can relieve chronic visceral hyperalgesia in rats with IBS, and such an effect may be correlated with inhibitory modulation of hyperactivity of neurons by means of down-regulating the high expression of NR1 in RVM of IBS model rats.

Effect of electro-acupuncture at different acupoints on neuropeptide and somatostatin in rat brain with irritable bowel syndrome.

OBJECTIVE: To compare the regulatory effects of electro-acupuncture (EA) at acupoints Zusanli (ST36) and Hegu (LI4) on the visceral hyper-sensitivity in the rat model of irritable bowel syndrome (IBS), and to explore the acting targets and specialty of acupoints. METHODS: Except 8 rats of the normal control group, the rest 32 rats were prepared to set up the IBS models. IBS animal model was prepared by enema with acetic acid. Model rats were divided into three groups. Except for rats in the model group for control, those in the other two groups were treated 20 min by EA on ST36 (EA-ST36) and LI4 (EA-LI4) respectively for 2 weeks to observe the effect on behavior response of viscera sensitivity. The changes of neuropeptide (NPY), the somatostatin (SS) levels in blood and tissues of brain and intestine were monitored as well. RESULTS: The volume thresholds for abdomen uplifting and back hunching were obviously increased after EA-ST36 (P<0.05), but showed insignificant change after EA-LI4. NPY contents lowered and SS contents increased in model rats; both EA-ST36 and EA-LI4 could raise the level of thalamic NPY (P<0.01 and P<0.05, respectively), but showed insignificant effects on NPY in colonic tissue. As for SS content, its colonic level could be reduced by EA-S36 and EA-LI4 (P<0.01 and P<0.05, respectively), however, its blood level was affected only by EA-ST36 (P<0.05). CONCLUSIONS: EA-ST36 or EA-LI4 could regulate the NPY in thalamus and SS in colonic tissue, the former could affect blood level of SS as well. It is deemed that NPY and SS may be the key substances for regulating the action of acupuncture in the brain-intestinal axis; their different levels could be regarded as an indicator for the functional difference between the acupoints.

Visceral responses to spinal manipulation.

While spinal manipulation is widely seen as a reasonable treatment option for biomechanical disorders of the spine, such as neck pain and low back pain, the use of spinal manipulation to treat non-musculoskeletal complaints remains controversial. This controversy is due in part to the perception that there is no robust neurobiological rationale to justify using a biomechanical treatment of the spine to address a disorder of visceral function. This paper therefore looks at the physiological evidence that spinal manipulation can impact visceral function. A structured search was conducted, using PubMed and the Index to Chiropractic Literature, to construct of corpus of primary data studies in healthy human subjects of the effects of spinal manipulation on visceral function. The corpus of literature is not large, and the greatest number of papers concerns cardiovascular function. Authors often attribute visceral effects of spinal manipulation to somato-autonomic reflexes. While this is not unreasonable, little attention is paid to alternative mechanisms such as somato-humoural pathways. Thus, while the literature confirms that mechanical stimulation of the spine modulates some organ functions in some cohorts, a comprehensive neurobiological rationale for this general phenomenon has yet to appear.

Mechanism of acupuncture regulating visceral sensation and mobility.

Chinese ancient medical scientists have long focused on the internal and external contacts between acupoints on the surface of the body and the viscera. The Miraculous Pivot (it is one of the earliest medical classics in China) stated, "Twelve regular channels belong to the zang-fu organs internally, and connect to the extremities and joints externally." Traditional Chinese medicine considers acupoints as defined areas where the Qi of viscera and meridians are transfused. These include the reaction points of visceral diseases on the body surface as well as the acupuncture trigger points that promote the flow of Qi and blood, and regulate visceral function. Chinese ancient medical scientists classified the specificity of the main acupoints in the body based on the meridian doctrine, which has been instructing clinical application for about 2000 years. Laws on the domino effect of acupoints have mainly focused on conclusions to clinical experiences. Indications of some acupoints exceed the practical paradigm since the excessive extension occurred during theory derivation. The current research direction on acupuncture focuses on three aspects: the effectiveness of acupuncture and moxibustion; the relevances and associations between meridians and viscera; and the physical and chemical properties and relevant physical basis of acupoints. The relevance between meridians and viscera is the central theory in the meridian doctrine, and acupoints are regarded as an important link in the relationship between meridians and viscera. Specific relationships between acupoints and target organs exist. Stimulating different acupoints on the body surface can help deal with different diseases, especially visceral diseases. In addition, acupoints have a dual function of reflecting and treating visceral diseases. There is no systemic research available on acupoint specificity, despite current knowledge and clinical experiences, which results in a weak foundation for acupuncture theory. This study focuses on the relevance and associations between meridians and viscera. A summary of the mechanisms of acupuncture regulating visceral sensation and mobility and the specific relationships between acupoints and their target organs are presented in this review.

Suspended moxibustion relieves chronic visceral hyperalgesia and decreases hypothalamic corticotropin-releasing hormone levels.

AIM: To evaluate the effect of suspended moxibustion (SM) on rectal sensory thresholds and to analyze the possible mechanisms involved in SM treatment of chronic visceral hypersensitivity (CVH) in rats. METHODS: SM was administered once daily to 37-d-old CVH rats for 7 d. The two pairs of acupoints (ST25 and ST37, bilateral) were simultaneously treated with SM. Each treatment lasted for 30 min. Rats undergoing treatment with SM were not anesthetized. Untreated CVH rats and normal rats were used as controls. The abdominal withdrawal reflex was determined 30-90 min after the seven treatments. The hypothalamic corticotropin-releasing hormone (CRH) mRNA level was measured using real-time quantitative reverse transcription-polymerase chain reaction. RESULTS: We found that SM treatment significantly decreased visceral sensitivity to colorectal distention in this rat model. In treated animals, SM also decreased the relative hypothalamic CRH mRNA expression level to control levels. CONCLUSION: Lower hypothalamic CRH levels may mediate the beneficial effects of SM in this rat irritable bowel syndrome model.

Electroacupuncture at ST-36 relieves visceral hypersensitivity and decreases 5-HT(3) receptor level in the colon in chronic visceral hypersensitivity rats.

PURPOSE: Visceral hypersensitivity is an important pathological mechanism of irritable bowel syndrome. Electroacupuncture (EA) could relieve chronic visceral hypersensitivity (CVH) in rats. However, little information is available about the mechanism. The aim of this study was to confirm the effects of EA at acupoint ST-36 (Zusanli) on CVH induced by the chemical colorectal irritation during postnatal development of rats, and to explore the possible 5-HT(3) receptor mechanism. METHODS: Rats were randomized into four groups, including the normal control group, CVH group, CVH with EA group, and CVH with sham EA group. The abdominal electromyogram (EMG) in response to colorectal distension was selected as the index for measurement of visceral hypersensitivity. 5-HT(3) receptors were analyzed through reverse transcription-polymerase chain reaction and western blot. RESULTS: EA at ST-36 significantly decreased evoked EMG. The expression of 5-HT(3) receptor in the colon was increased in rats with CVH, and decreased after EA treatment. CONCLUSIONS: EA at acupoint ST-36 attenuates CVH in rats and decreases 5-HT(3) receptor level in the colon. Decreased 5-HT(3) receptor level in the colon may mediate the beneficial effect of EA in rats with CVH.

Measurement of electrical resistance of dermal-visceral zones as a diagnostic tool for gynecologic disorders.

BACKGROUND: Non-invasive screening tests may allow early diagnosis and prompt treatment, thereby potentially reducing morbidity and mortality and reducing costs for the community. This may be especially important for gynecologic pathologies that are difficult to promptly diagnose, such as endometriosis or ovarian cancer. OBJECTIVES: To evaluate the reliability of measuring skin resistance using the Medex Test for screening and diagnosis of gynecologic pathologies in a blinded single-center study. METHODS: We enrolled 150 patients: 59 with a functional disorder and 91 with an organic disease. Measurements were carried out in all patients and the results were analyzed separately by a second physician who was blinded to the patients' diagnosis. RESULTS: A high correlation was found between the clinical diagnosis and the results of the measurement of electrical skin resistance, with a specificity of 76.3% (45/59) for functional disorders and a sensitivity of 85.7% (78/91) for organic disorders, positive predictive value of 84.8% (78/92) and negative predictive value 77.6% (45/58). The kappa value for the results was 0.622, representing a value much better than expected randomly. CONCLUSIONS: The Medex Test has a good specificity and a high sensitivity for the diagnosis of gynecologic disorders. Further prospective studies are needed to validate these preliminary findings.

Effects of moxibustion on dynorphin and endomorphin in rats with chronic visceral hyperalgesia.

AIM: To observe the analgesic effects of moxibustion in rats with chronic visceral hyperalgesia and its influence on the concentration of dynorphin (Dyn) and endomorphin (EM) in spinal cord. METHODS: The rat model of chronic visceral hyperalgesia was established by colorectal distention (CRD). In moxibustion (MX) group, moxibustion was applied once daily for 7 d; in sham moxibustion (SM) group, moxibustion was given to the same acupoints but with the non-smoldered end of the moxa stick. Model control (MC) group and normal control group were also studied. The scoring system of abdominal withdrawal reflex was used to evaluate visceral pain for behavioral assessment. Enzyme linked immunosorbent assay was performed to determine the concentrations of Dyn and EM in spinal cord. RESULTS: Moxibustion significantly decreased visceral pain to CRD in this rat model, and no significant difference was detected between the SM group and the MC group. In MX group, moxibustion also increased the concentrations of Dyn and EM in spinal cord, and no significant difference was found between the SM group and the MC group. CONCLUSION: Moxibustion therapy can significantly enhance the pain threshold of rats with chronic visceral hyperalgesia, and the effect may be closely related to the increased concentration of Dyn and EM in spinal cord.

Technical aspects of spinal cord stimulation for managing chronic visceral abdominal pain: the results from the national survey.

UNLABELLED: BACKGROUND, OBJECTIVES, AND METHODS: A few recent reports suggested that spinal cord stimulation (SCS) effectively suppresses chronic abdominal pain. However, there is no consensus on patient selection or technical aspects of SCS for such pain. That is why we conducted national survey and collected 76 case reports. There were six incompletely filled reports, so we analyzed 70 cases. RESULTS: There were 43 female and 27 male patients. SCS was trialed in an average of 4.7 days (median of 4 days). In most patients, the leads were positioned for the SCS trial with their tips at the level of the T5 vertebral body (26 patients) or T6 vertebral body (15 patients). Four patients failed SCS trial: their average baseline visual analog scale (VAS) pain score was 7 +/- 2.4 cm and did not improve at the conclusion of the trial (6.5 +/- 1.9 cm; P = 0.759). Pain relief exceeded 50% in 66 of 70 patients reported. Among those, VAS pain score before the trial averaged 7.9 +/- 1.8 cm. During the trial VAS pain scores decreased to 2.45 +/- 1.45 cm (P < 0.001). The opioid use decreased from 128 +/- 159 mg of morphine sulfate equivalents a day to 79 +/- 112 mg (P < 0.017). During permanent implantation most of the physicians used two octrode leads and were positioned midline at T5-6 levels. The average patient follow-up was 84 weeks. VAS pain scores before an implant were 8 +/- 1.9 cm, while after the implant 2.49 +/- 1.9 cm. The opioid use before an implant was 158 +/- 160 mg and at the last office visit after the implant 36 +/- 49 mg. CONCLUSION: In conclusion, it seems that the SCS for the treatment of the abdominal visceral pain may provide a positive patient long-term experience, significant improvements in pain scores and a decrease in opioid use.

The alleviating pain effect of aqueous extract from tong-xie-yao-fang, on experimental visceral hypersensitivity and its mechanism.

Tong-Xie-Yao-Fang (TXYF) is a prescription in traditional chinese medicine (TCM), used for relieving abdominal pain associated with irritable bowel syndrome. The aim of the present study was to investigate the effects and mechanism of TXYF on experimental visceral hypersensitivity (VH) models. TXYF affected the abdominal withdrawal reflex produced by colonic distention in maternal separation-induced visceral hypersensitivity rats, in a dosage-dependent manner. TXYF significantly decreased serotonin (5-HT) levels in serum and corticotrophin releasing factor (CRF) concentrations in the brain. Moreover, it was found that VH alleviation by TXYF was dependent on the substance P (SP) expression in the colon mucosa. These results suggest that TXYF attenuates behavioral hyperalgesia by regulating substance associated with the brain-gut axis, including decreasing the expression of 5-HT and SP in the periphery and that of CRF in the center.

Acupuncture at both ST25 and ST37 improves the pain threshold of chronic visceral hypersensitivity rats.

Previous studies demonstrated the efficacy of electro-acupuncture (EA) in relieving chronic visceral hypersensitivity (CVH) in IBS rats. However, ST25 which is a key acupoint for patients with IBS has not been reported in these experiments. Eight CVH rats were treated by EA at both ST25 and ST37 for 20 min, once daily for seven consecutive days, model rats (n = 8) and normal rats (n = 8) as controls. After the first EA treatment, the abdominal withdrawal reflex scores were investigated to evaluate the pain threshold. After seven EA treatments, the concentrations of 5-hydroxytryptamine (5-HT), 5-HT3 receptor (5-HT3R) and 5-HT4 receptor (5-HT4R) in colon tissue were assayed quantitatively by enzyme-linked immunosorbent assay. The results showed that EA improved the pain threshold of CVH rats, reduced the 5-HT concentration and increased the 5-HT4R concentration, but had no effect on the 5-HT3R concentration. Further studies are needed to optimize the choice of two-matching points for EA in the treatment of CVH rats.

Visceral analgesics: drugs with a great potential in functional disorders?

Irritable bowel syndrome remains an incompletely understood, common syndrome with significant unmet medical needs. In IBS patients, abdominal pain is a primary factor related to quality of life impairment, symptom severity and health care utilization, and chronic visceral hyperalgesia has been identified as an important aspect of IBS pathophysiology. However, the development of therapies aimed at reducing this hyperalgesia (visceral analgesics) has been only partially successful despite preclinical evidence supporting the potential usefulness of several preclinical compounds aimed at peripheral as well as central targets.

[Influence of connexin 43 gene knockout on the analgesic effect of acupuncture in visceral pain mice].

OBJECTIVE: To explore the possible central and peripheral mechanisms of connexin 43 gene knockout in acupuncture analgesia. METHODS: Fifty-four wide type (WT) mice and 54 connexin 43 gene knockout (heterozygote, HT) mice were randomly divided into WT control group, WT model group, WT acupuncture group, HT control group, HT model group and HT acupuncture group (n = 18/group). Visceral pain model was established by intraperitoneal injection of 0.6% acetic acid (0. 1 mL/10 g). "Zhongwan" (CV 12) and bilateral "Zusanli" (ST 36) were punctured with filiform needles and stimulated for 30 min by manipulating the needle for 30 s every 5 min. The latency and the number of body-writhing response were observed and the contents of beta-endorphin (beta-EP) in hypothalamus and serum prostaglandin E2 (PGE2) were detected with radioimmunoassay (RIA). RESULTS: There was no significant difference in the latency and the number of body-writhing response, and contents of hypothalamic beta-EP and serum PGE2 between HT and WT control groups (P > 0.05). Compared with the corresponding control groups, the latency of body-writhing in WT model and HT model groups shortened significantly and the number of body- writhing increased considerably in two model groups (P < 0.01). While in comparison with WT model group, the latency of body-writhing prolonged significantly and the number of body-writhing decreased apparently in WT acupuncture group (P < 0.01); but no marked differences were found between HT model and HT acupuncture groups in these two indexes (P > 0.05). Compared with the corresponding control groups, the contents of both beta-EP and PGE2 increased obviously in WT model and HT model groups (P < 0.05). In comparison with WT model group, beta-EP levels in WT acupuncture group increased further significantly (P < 0.05), and serum PGE2 in WT acupuncture group decreased obviously (P < 0.05); but no significant changes were found between HT model and HT acupuncture groups in beta-EP and PGE2 levels (P > 0.05). CONCLUSION: Acupuncture has a marked antinociceptive effect in WT mice with visceral pain, which may be related to its effects in increasing hypothalamic beta-EP and decreasing serum PGE2; while in connexin 43 gene knockout mice, all the above-mentioned effects of acupuncture are eliminated, indicating an important role of connexin 43 in the analgesic effect of acupuncture.

Anterior cingulate cortex modulates visceral pain as measured by visceromotor responses in viscerally hypersensitive rats.

BACKGROUND & AIMS: We have identified that the anterior cingulate cortex (ACC) neurons are responsive to colorectal distention (CRD) and shown that sensitization of ACC neurons occurs in viscerally hypersensitive rats. However, the role of the ACC in pain response has not been clearly defined. We aimed to determine if ACC neuron activation enhances visceral pain in viscerally hypersensitive rats and to identify the receptor involved in facilitation of visceral pain. METHODS: The nociceptive response (visceromotor response [VMR]) to CRD was recorded in normal and viscerally hypersensitive rats induced by colonic anaphylaxis. The ACC was stimulated electrically, and ACC lesions were generated with ibotenic acid. l-glutamate, alpha-amino-3-hydroxy-5-methyl-isoxozole propionic acid receptor antagonist cyanonitroquinoxaline dione, and N-methyl-d-aspartate receptor antagonist aminophosphonopentanoic acid were microinjected into the rostral ACC. RESULTS: Electrical stimulation of the rostral ACC enhanced the VMR to CRD in normal rats. ACC lesions caused a decrease in the VMR in viscerally hypersensitive rats but had no effect in normal rats. ACC microinjection of 2 mmol/L glutamate increased the VMR to CRD (10 mm Hg) in viscerally hypersensitive rats, and 20 mmol/L glutamate induced a more potent VMR in viscerally hypersensitive than in normal rats. Cyanonitroquinoxaline dione did not affect the VMR in either group. Aminophosphonopentanoic acid significantly suppressed the VMR in viscerally hypersensitive rats but not in normal rats. CONCLUSIONS: The ACC plays a critical role in the modulation of visceral pain responses in viscerally hypersensitive rats. This process appears to be mediated by enhanced activities of glutamate N-methyl-d-aspartate receptors.

Spinal cord stimulation is an effective treatment for the chronic intractable visceral pelvic pain.

OBJECTIVE: Recent studies have demonstrated significant involvement of dorsal column pathways in transmission of visceral pelvic pain. Spinal cord stimulation (SCS) suppresses visceral response to colon distension in an animal model and therefore may be an effective therapy for chronic pelvic pain of visceral origin. We are reporting on the value of neurostimulation for chronic visceral pelvic pain in six female patients with the diagnosis of long-standing pelvic pain (history of endometriosis, multiple surgical explorations, and dyspareunia). DESIGN AND SETTINGS: Case-series report. All patients received repeated hypogastric blocks (in an average of 5.3 blocks) with a significant pain relief for a period ranging from 1 to 6 weeks. Three received neurolytic hypogastric block with the pain relief of 3, 8, and 12 months, respectively. Following psychological evaluation and clearance by our Multidisciplinary Committee on Implantable Devices, they all underwent SCS trial for 7-14 days. All patients received SCS systems with dual leads (Compact or Quad leads, Medtronic Inc., Minneapolis, MN, USA). RESULTS: The average follow-up was 30.6 months. Median visual analog scale pain score decreased from 8 to 3. All patients had more than 50% of the pain relief. Pain Disability Index changed from an average of 57.7 +/- 12 to 19.5 +/- 7. Opiate use decreased from an average 22.5 mg to 6.6 mg of morphine sulfate milligram equivalents per day. CONCLUSION: It appears that SCS may have a significant therapeutic potential for treatment of visceral pelvic pain.

Review article: uncomplicated diverticular disease of the colon.

Diverticular disease of the colon is the fifth most important gastrointestinal disease in terms of direct and indirect health care costs in western countries. Uncomplicated diverticular disease is defined as the presence of diverticula in the absence of complications such as perforation, fistula, obstruction and/or bleeding. The distribution of diverticula along the colon varies worldwide being almost always left-sided and directly related to age in western countries and right-sided where diet is rich in fibre. The pathophysiology of diverticular disease is complex and relates to abnormal colonic motility, changes in the colonic wall, chronic mucosal low-grade inflammation, imbalance in colonic microflora and visceral hypersensitivity. Moreover, there can be genetic factors involved in the development of colonic diverticula. The use of non-absorbable antibiotics is the mainstay of therapy in patients with mild to moderate symptoms, and the effect of fibre-supplementation alone does not appear to be significantly different from placebo, although no definite data are available. More recently, alternative treatments have been reported. Mesalazine acts as a local mucosal immunomodulator and has been shown to improve symptoms and prevent recurrence of diverticulitis. In addition, probiotics have also been shown to be beneficial by re-establishing a normal gut microflora. In this study, the current literature on uncomplicated diverticular disease of the colon is reviewed.

Electro-acupuncture attenuates stress-induced defecation in rats with chronic visceral hypersensitivity via serotonergic pathway.

Acupuncture has long been used for patients with irritable bowel syndrome. However, it has remained unclear. The aim of this study was to testify the effect of electro-acupuncture(EA) on (1) visceral hypersensitivity induced by the mechanical colorectal irritation during postnatal development of rats, and (2) stress-induced colonic motility changes on rats with chronic visceral hypersensitivity. The abdominal withdrawal reflex (pain threshold and score) for visceral hypersensitivity and fecal pellet output for motor dysfunction were selected as two indexes for measurement. In addition, the effect of EA on 5-HT(4a) receptor and serotonin transporter (SERT) expression in the colon mucosa was analyzed semi-quantitatively through immunohistochemistry and 5-HT concentration in the colon tissue was observed through spectro-photo-fluorimeter detection, respectively. Our results showed that EA significantly elevated pain threshold, decreased the scores and also decreased fecal pellet output during water avoid stress. Furthermore, EA decreased 5-HT concentration in colon in rats with CVH and CVH rats with water avoidance stress, and increased the 5-HT(4a) and SERT expression in rats with CVH. Thus, it can be concluded that EA attenuates behavioral hyperalgesia and stress-induced colonic motor dysfunction in CVH rats via serotonergic pathway.

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

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

Patients with chest pain and occult gastroesophageal reflux demonstrate visceral pain hypersensitivity which may be partially responsive to acid suppression.

OBJECTIVES: Mechanisms of chest pain in gastroesophageal reflux disease (GERD) are poorly understood. The recent demonstration in healthy subjects that lower esophageal acid exposure induces pain hypersensitivity within the non-acid-exposed upper esophagus (secondary allodynia) raises the possibility that an increase in spinal neuronal excitability (i.e., central sensitization) contributes to chest pain in GERD. The aim of this study was to determine whether in patients with unexplained chest pain, acid reflux contributes to esophageal pain hypersensitivity. METHODS: In 14 patients with chest pain and GERD and 8 healthy volunteers, electrical pain thresholds (PT) were recorded from the upper esophagus before, and then repeatedly for 90 min after either hydrochloric acid (0.15 M) or saline (0.15 M) infusion into the lower esophagus. Six patients underwent a repeat study after 6 wk of high-dose proton pump inhibitor (PPI) therapy. RESULTS: GERD patients had lower resting upper esophageal PT than in healthy subjects (40.8 +/- 9 mA and 70.4 +/- 11 mA, respectively; p= 0.018). Acid infusion reduced PT in the non-acid-exposed upper esophagus in healthy subjects, but not in the patients (area under curve [AUC] - 304 +/- 333 and 786 +/- 464; p= 0.03, respectively). Following PPI therapy, resting PT increased (34.65 +/- 13.4 to 40.5 +/- 12.5 mA; p= 0.03), and a reduction in PT now occurred in acid infusion (AUC - 369 +/- 321; p= 0.03). CONCLUSIONS: Patients with unexplained chest pain and occult GERD have esophageal pain hypersensitivity that is PPI responsive. The increase in resting PT and secondary allodynia only following PPI therapy suggests that pain hypersensitivity in these GERD patients may partially be the result of central sensitization.