Balloon Distension Research Articles

Role of sympathetic nervous system in rat model of chronic visceral pain.

Changes in central pain modulation have been implicated in generalized pain syndromes such as irritable bowel syndrome (IBS). We have previously demonstrated that reduced descending inhibition unveils a role of sympathoneuronal outflow in decreasing peripheral sensory thresholds, resulting in stress-induced hyperalgesia. We investigated whether sympathetic nervous system (SNS) exacerbation of pain sensation when central pain inhibition is reduced is relevant to chronic pain disorders using a rat colon irritation (CI) model of chronic visceral hypersensitivity with hallmarks of IBS. Rats were treated to a series of colorectal balloon distensions (CRD) as neonates resulting in visceral and somatic hypersensitivity and altered stool function that persists into adulthood. The visceral sensitivity was assessed by recording electromyographic (EMG) responses to CRD. Somatic sensitivity was assessed by paw withdrawal thresholds to radiant heat. The effects on the hypersensitivity of (i) inhibiting sympathoneuronal outflow with pharmacological and surgical interventions and (ii) enhancing the outflow with water avoidance stress (WAS) were tested. The alpha2-adrenergic agonist, clonidine, and the alpha1-adrenergic antagonist, prazosin, reduced the visceral hypersensitivity and WAS enhanced the pain. Chemical sympathectomy with guanethidine and surgical sympathectomy resulted in a loss of the chronic visceral hypersensitivity. The results support a role of the SNS in driving the chronic visceral and somatic hypersensitivity seen in CI rats. The findings further suggest that treatments that decrease sympathetic outflow or block activation of adrenergic receptors on sensory nerves could be beneficial in the treatment of generalized pain syndromes.

Water avoidance stress induces visceral hyposensitivity through peripheral corticotropin releasing factor receptor type 2 and central dopamine D2 receptor in rats.

Water avoidance stress (WAS) is reported to induce functional changes in visceral sensory function in rodents, but the results which have been demonstrated so far are not consistent, i.e., hypersensitivity or hyposensitivity. We determined the effect of WAS on visceral sensation and evaluated the mechanisms of the action. Visceral sensation was assessed by abdominal muscle contractions induced by colonic balloon distention, i.e., visceromotor response (VMR), measured electrophysiologically in conscious rats. The electromyogram electrodes were acutely implanted under anesthesia on the day of the experiment. The threshold of VMR was measured before and after WAS for 1 h. To explore the mechanisms of WAS-induced response, drugs were administered 10 min prior to the initiation of WAS. WAS significantly increased the threshold of VMR, and this effect was no longer detected at 24 h after. Intraperitoneal injection of astressin2 -B (200 μg/kg), a corticotropin releasing factor (CRF) receptor type 2 antagonist abolished the response by WAS. Subcutaneous (sc) injection of sulpiride (200 mg/kg), a dopamine D2 receptor antagonist blocked the response, while sc domperidone (10 mg/kg), a peripheral dopamine D2 receptor antagonist did not alter it. Naloxone (1 mg/kg, sc), an opioid antagonist did not modify it either. WAS induced visceral hyposensitivity through peripheral CRF receptor type 2 and central dopamine D2 receptor, but not through opioid pathways. As altered pain inhibitory system was reported to be observed in the patients with irritable bowel syndrome, CRF and dopamine signaling might contribute to the pathophysiology.

Esophageal mucosa exfoliation induced by oxalic acid poisoning: A case report.

This study reports the case of a 44-year-old woman with oral oxalic acid poisoning. As the illness progressed, the patient exhibited severe metabolic acidosis, large-area esophageal mucosa injury and acute kidney injury, which required dialysis. A guide wire slipped out of position during the process of hemodialysis and moved back and forth in the veins, but was removed successfully by interventional endovascular treatment. However, the patient's esophageal mucosa exfoliated, which lead to severe benign esophageal stenosis and dysphagia. Balloon distention was conducted twice in the upper digestive tract using X-ray location in combination with a dumb-bell bladder and interventional wire. The patient exhibited convulsions, shock, embolism and loss of consciousness while undergoing the second balloon distention procedure. Following symptomatic treatment, the patient eventually remained in a stable condition, the digestive tract expansion procedure was not resumed and a jejunostomy was performed in order to facilitate enteral nutrition, which was administered via the jejunum and had little stimulatory effect on the pancreas. Following various treatments, the patient's condition improved markedly, with renal function returning to normal.

Altered brain responses in subjects with irritable bowel syndrome during cued and uncued pain expectation.

A majority of the subjects with irritable bowel syndrome (IBS) show increased behavioral and brain responses to expected and delivered aversive visceral stimuli during controlled rectal balloon distension, and during palpation of the sigmoid colon. We aimed to determine if altered brain responses to cued and uncued pain expectation are also seen in the context of a noxious somatic pain stimulus applied to the same dermatome as the sigmoid colon. A task-dependent functional magnetic resonance imaging technique was used to investigate the brain activity of 37 healthy controls (18 females) and 37 IBS subjects (21 females) during: (i) a cued expectation of an electric shock to the abdomen vs a cued safe condition; and (ii) an uncued cross-hair condition in which the threat is primarily based on context vs a cued safe condition. Regions within the salience, attention, default mode, and emotional arousal networks were more activated by the cued abdominal threat condition and the uncued condition than in the cued safe condition. During the uncued condition contrasted to the cued safe condition, IBS subjects (compared to healthy control subjects) showed greater brain activations in the affective (amygdala, anterior insula) and attentional (middle frontal gyrus) regions, and in the thalamus and precuneus. These disease-related differences were primarily seen in female subjects. The observed greater engagement of cognitive and emotional brain networks in IBS subjects during contextual threat may reflect the propensity of IBS subjects to overestimate the likelihood and severity of future abdominal pain.

Psychological factors selectively upregulate rectal pain perception in hypersensitive patients with irritable bowel syndrome.

Visceral hypersensitivity and psychological symptoms are frequent features in irritable bowel syndrome (IBS). Exploring mechanistic pathways leading to visceral hypersensitivity is of importance to direct future studies and treatment options. In this study, we evaluated the contribution of psychological factors to the perception of painful and non-painful rectal sensations in hyper- vs normosensitive IBS patients. We included 138 IBS patients (Rome II criteria) who underwent an ascending method of limited rectal balloon distension paradigm. At the end of each distension step, subjects rated the perceived intensity of non-painful ('unpleasantness') and painful rectal sensations on visual analog scales. Sensitivity status was determined based on pain thresholds. Anxiety, depression and somatization were assessed by questionnaires. Mixed models were used to test the relationship between sensitivity status, psychological variables, and pain & unpleasantness ratings upon increasing distension. Hypersensitive IBS patients had lower sensory thresholds for pain, first perception, urge to defecate, and discomfort (p<0.0001). Upon increasing distension, they rated both painful and non-painful sensations as more intense than normosensitive patients (p<0.0001). Psychological factors were associated with higher painratings during distension in hypersensitive (p<0.006-0.0001), but not in normosensitive patients. Anxiety, but not depression or somatization, was associated with increased intensity ratings of non-painful sensations (p<0.001), independent of sensitivity status. Hypersensitive IBS patients are characterized by increased perception of pain, but also of non-painful sensations. Psychological factors increase the perception of painful sensations in hypersensitive patients only, whereas non-painful visceral sensations were exaggerated in anxious patients regardless of the sensitivity status.

Systematic review: instruments to assess abdominal pain in irritable bowel syndrome.

Consensus on standard methods to assess chronic abdominal pain in patients with irritable bowel syndrome (IBS) is currently lacking. To systematically review the literature with respect to instruments of measurement of chronic abdominal pain in IBS patients. Systematic literature search was performed in PubMed/Medline databases for studies using pain measurement instruments in patients with IBS. One hundred and ten publications were reviewed. A multitude of different instruments is currently used to assess chronic abdominal pain in IBS patients. The single-item methods, e.g. the validated 10-point numeric rating scale (NRS), and questionnaires assessing gastrointestinal symptoms severity, focus mostly on the assessment of only the intensity of abdominal pain. Of these questionnaires, the validated IBS-Symptom Severity Scale includes the broadest measurement of pain-related aspects. General pain questionnaires and electronic momentary symptom assessment tools have been used to study abdominal pain in IBS patients, but have not yet been validated for this purpose. The evidence for the use of provocation tests, e.g. the rectal barostat with balloon distention, for measurement of abdominal pain in IBS is weak, due to the poor correlation between visceral pain thresholds assessed by provocation tests and abdominal pain as assessed by retrospective questionnaires. The multitude of different instruments to measure chronic abdominal pain in IBS makes it difficult to compare endpoints of published studies. There is need for validated instruments to assess chronic abdominal pain in IBS patients, that overcome the limitations of the currently available methods.

A 4-week Pilot Study With the Cannabinoid Receptor Agonist Dronabinol and Its Effect on Metabolic Parameters in a Randomized Trial

PurposeDronabinol (synthetic Δ9- tetrahydrocannabinol) is used in patients with nausea and vomiting from chemotherapy and in AIDS patients for appetite stimulation. Recently, dronabinol was used to successfully treat visceral hypersensitivity causing noncardiac chest pain. With widening uses of this medication, we aim to explore its effects on metabolic parameters in long-term dosing and hypothesize that it will not affect major metabolic parameters. MethodsA double-blind, placebo-controlled, 28-day trial was performed with patients 18 to 75 years old without cardiac disease. Patients had at least 2 weekly episodes of chest pain for the last 3 months and evidence of esophageal hypersensitivity after balloon distention testing. Prior use of pain medication, psychiatric diagnosis, or significant medical comorbidities precluded inclusion in the study. Patients were randomized to receive 5 mg dronabinol or placebo twice daily with metabolic parameters examined before and after the use of medication. FindingsThirteen patients completed the study (7 with dronabinol [6 women and 1 man] and 6 with placebo [5 women and 1 man]). None of the measured values, including body mass index, HDL, triglycerides, calculated LDL, high-sensitivity C-reactive protein, glucose, insulin, leptin, aspartate aminotransferase, alanine aminotransferase, LDH, or non-HDL, differed significantly in either group before or after treatment. In general, treatment with dronabinol coincided with favorable trends in some parameters, although these trends were not statistically significant. ImplicationsDronabinol administration does not significantly affect basic metabolic components after a period of 28 days. The implications of these findings are important because dronabinol may be able to be used in patients with metabolic disorders. The favorable trends observed here warrant further exploration into its long-term effects. ClinicalTrials.gov identifier: NCT01598207.

Characterization of the peristaltic reflex in murine distal colon.

Ascending and descending neuromuscular reflexes play an important role in gastrointestinal motility. However, the underlying mechanisms in colon are incompletely understood. Nerve stimulation (NS)- and balloon distention (BD)-mediated reflexes in distal colonic circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) of mice were investigated using conventional intracellular recordings. In the CSM, NS evoked ascending purinergic inhibitory junction potentials (IJPs), whereas BD induced atropine-sensitive ascending depolarization with superimposed action potentials (APs). The ascending depolarization reached a peak ∼4-7 s after the onset of distention and gradually returned to baseline after termination of the distention. In the LSM, NS produced an ascending biphasic IJP followed by a train of atropine-sensitive APs. Both stimuli produced similar descending IJPs in CSM and LSM, which were blocked by MRS-2500 and MRS-2179, putative purinergic receptor blockers. These data indicate that in the murine distal colon, descending purinergic inhibition in both CSM and LSM occurs. Ascending responses are more complex, with NS producing both inhibition and excitation to CSM and LSM, and BD evoking only cholinergic excitation.

Startle responding in the context of visceral pain

This study aimed to investigate affective modulation of eye blink startle by aversive visceral stimulation. Startle blink EMG responses were measured in 31 healthy participants receiving painful, intermittent balloon distentions in the distal esophagus during 4 blocks (positive, negative, neutral or no pictures), and compared with startles during 3 ‘safe’ blocks without esophageal stimulations (positive, negative or neutral emotional pictures). Women showed enhanced startle during blocks with distentions (as compared with ‘safe’ blocks), both when the balloon was in inflated and deflated states, suggesting that fear and/or expectations may have played a role. Men's startle did not differ between distention and non-distention blocks. In this particular study context affective picture viewing did not further impose any effect on startle eye blink responses. The current results may contribute to a better understanding of emotional reactions to aversive interoceptive stimulation.

Neonatal vaginal irritation results in long-term visceral and somatic hypersensitivity and increased hypothalamic-pituitary-adrenal axis output in female mice.

Experiencing early life stress or injury increases a woman's likelihood of developing vulvodynia and concomitant dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. To investigate the outcome of neonatal vaginal irritation (NVI), female mouse pups were administered intravaginal zymosan on postnatal days 8 and 10 and were assessed as adults for vaginal hypersensitivity by measuring the visceromotor response to vaginal balloon distension (VBD). Western blotting and calcium imaging were performed to measure transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) in the vagina and innervating primary sensory neurons. Serum corticosterone (CORT), mast cell degranulation, and corticotropin-releasing factor receptor 1 (CRF1) expression were measured as indicators of peripheral HPA axis activation. Colorectal and hind paw sensitivity were measured to determine cross-sensitization resulting from NVI. Adult NVI mice had significantly larger visceromotor response during VBD than naive mice. TRPA1 protein expression was significantly elevated in the vagina, and calcium transients evoked by mustard oil (TRPA1 ligand) or capsaicin (TRPV1 ligand) were significantly decreased in dorsal root ganglion from NVI mice, despite displaying increased depolarization-evoked calcium transients. Serum CORT, vaginal mast cell degranulation, and CRF1 protein expression were all significantly increased in NVI mice, as were colorectal and hind paw mechanical and thermal sensitivity. Neonatal treatment with a CRF1 antagonist, NBI 35965, immediately before zymosan administration largely attenuated many of the effects of NVI. These results suggest that NVI produces chronic hypersensitivity of the vagina, as well as of adjacent visceral and distant somatic structures, driven in part by increased HPA axis activation.

Rapid balloon distension as a tool to study cortical processing of visceral sensations and pain

The processing of discomfort and pain in the central nervous system is normally studied with experimental methods, but it is mandatory that they are reliable over time to ensure that any interventions will result in valid results. We investigated reliability of rapid balloon distension in the rectum to elicit cortical evoked potentials (CEPs) to study the reliability of central processing of visceral sensation and discomfort/pain. Eighteen healthy volunteers had two series of rectal balloon distensions performed on two separate days. Individualized balloon pressure, corresponding to pain detection threshold or to the maximum possible distension (30 psi), was used. Within- and between days reliability was measured in terms of amplitudes and latencies of the CEP global field power, topography and underlying brain networks. There were two prominent peaks in the CEP recordings at mean latencies of 157 and 322 ms. There were no differences in latencies or amplitudes (p = 0.3) and they passed the Bland-Altman test for reproducibility. There were no differences in topographies (p > 0.7). Brain source connectivity revealed the cingulate-operculum network as the most consistent network within and between subjects. There were no differences in the location of brain sources in this network (p = 0.9) and the source coordinates were reproducible. Finally, the cingulate source generally had higher strength than operculum source (p < 0.001). A reliable method to study central mechanisms underlying visceral sensation and pain was established. The method may improve our understanding of visceral pain and could be an objective method for studying efficacy of analgesics on visceral pain.

Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence.

The pathophysiology behind idiopathic fecal incontinence (IFI) is poorly understood. We hypothesized abnormal sensory pathways along the brain-gut axis as a key player in this disease, reflected in cortical evoked potentials (CEP) from mechanical stimuli of the rectum and the anal canal. CEPs were recorded during repeated rapid balloon distensions of the rectum and anal canal in 19 women with IFI (mean age: 60 ± 14, mean Wexner score: 14.7 ± 2.9) and in 19 healthy women (mean age: 56 ± 11, mean Wexner score: 1.1 ± 1.3). Latencies, amplitudes and topography of CEPs elicited by rectal distension were compared between the groups. CEPs from both rectal and anal distensions were examined using spectral band analysis of single sweeps determining the relative amplitude of five spectral bands as a proxy of neuronal processing. Compared to controls IFI patients had prolonged latency of CEPs from rectal distension by up to 27% (p < 0.001) while amplitudes and topography were similar (all p > 0.7 and all p > 0.23). Spectral analysis of CEPs from rectal distensions showed no difference (all p > 0.1) between groups. However, analysis of CEPs following distension of the anal canal resulted in abnormally low activity in beta (8-12 Hz; p < 0.001) band and high activity in the gamma (32-70 Hz; p = 0.04) band in patients. IFI seems to be associated with impaired ano-rectal sensory functions in both the afferent fibers to the brain and the cortical processing of anal sensory pathways. This may play a central role for the pathogenesis of IFI.

501 Corticotrophin Releasing Hormone (CRH) Sensitizes the Esophagus to Balloon Distention Due to an Increase in Esophageal Contractile Amplitude

501 Corticotrophin Releasing Hormone (CRH) Sensitizes the Esophagus to Balloon Distention Due to an Increase in Esophageal Contractile Amplitude

Therapeutic value of spinal cord stimulation in irritable bowel syndrome: a randomized crossover pilot study.

Irritable bowel syndrome (IBS) is characterized by abdominal pain and changed bowel habits. Spinal cord stimulation (SCS) has been used for treatment of chronic pain syndromes. Animal studies have shown SCS to reduce the reaction to colonic balloon distension, known to be increased in IBS patients. To elucidate the potential for SCS as treatment for IBS, a pilot study was performed. Ten IBS patients (age 26-56 yr) were recruited. A SCS system with a four-polar electrode was implanted at the T5-T8 level. After a 2-wk run-in, a randomized, crossover design SCS during 6 wk was compared with no stimulation, with an ensuing stimulation period for 12 wk; total study period 28 wk. Patients recorded pain level, pain attacks, diarrheas, and global quality of life in a diary. At end of the study patients could choose to retain their SCS system or have it removed. Nine patients completed the whole trial. During stimulation periods the median pain scores were significantly reduced from visual analogue scale (VAS) 7 (4-8) to 3 (2.5-7) and to 4 (2-6) during early and late stimulation periods, respectively (P < 0.03-0.04). Pain attacks were numerically reduced. A few patients reported reduced number of diarrheas. After study termination, six patients chose to retain their SCS system. To conclude, SCS is a minimally invasive treatment option for pain in IBS. With SCS the pain level was reduced though with merely a trend for number of attacks and diarrheas. The efficacy of SCS in IBS pain indicates a possible usefulness in other painful bowel disorders.

The efficacy of balloon dilation in achalasia is the result of stretching of the lower esophageal sphincter, not muscular disruption.

SummaryPneumatic dilation (PD) of the lower esophageal sphincter (LES) in achalasia is a major palliative treatment. It is generally believed, although never substantiated, that therapeutic efficacy of ballooning in achalasia is the result of the disruption and tearing of the muscular layers of the LES. To clarify this issue, we investigated the frequency of muscular disruption at the LES, 24 hours after PD, by employing the endoscopic ultrasound (EUS), in a group of 43 consented patients with achalasia. Between July 2009 and March2012, 51 consecutive adult patients with tentative diagnosis of achalasia, some with recurrence of symptoms after an earlier treatment with balloon dilation, were evaluated and underwent PD, using Rigiflex balloon without major adverse effect. Out of the 51 evaluated, 43 eligible and consenting patients who underwent EUS, 24 hours after PD, using Olympus GF‐UE 160 echoendoscope and an Aloka Prosound probe at 7.5 MHZ, are the subjects of this study. The EUS in 43 eligible patients revealed an intact LES in 36 (83.7%), small area of muscular disruption in 5 (11.6%) and small hematoma in 2 patients (4.6%). Our data convincingly demonstrate that the clinical effectiveness of balloon dilation in achalasia is not the result of muscular disruption, but of circumferential stretching of the LES. Our findings on the mechanism of action of PD in achalasia could result in modifying the current method of dilation for a safer procedure, by slowing the rate of inflation and allowing the sphincter to slowly stretch itself to the distending balloon.

Assessing pyloric sphincter pathophysiology using EndoFLIP in patients with gastroparesis.

Pyloric dysfunction has been associated with gastroparesis, particularly diabetic gastroparesis. Endoscopic functional luminal imaging probe (EndoFLIP) uses 16 sensors inside a balloon that is inflated inside a sphincter to assess physiologic characteristics. The aim of this study was to measure the pressure, diameter, cross-sectional area (CSA), and distensibility of the pylorus using EndoFLIP in patients with gastroparesis. In addition, the relationship between pyloric pathophysiology with gastroparesis etiology, symptoms, and gastric emptying was assessed. EndoFLIP was performed in 54 patients (39 idiopathic gastroparesis, 15 diabetic gastroparesis). The EndoFLIP catheter was passed endoscopically so that the balloon straddled the pylorus. Pressure, diameter, CSA, and distensibility of the pylorus were measured at 20, 30, 40, and 50 cc balloon volume. Pyloric sphincter contour was seen best at 40 cc balloon distension (diameter 12.2 ± 0.44 mm, CSA 125.2 ± 9.15 mm(2), pressure 18.0 ± 1.23 mmHg, length 1.59 ± 0.34 cm, distensibility 10.7 ± 2.57 mm(2)/mmHg). There was a wide range seen in diameter (5.6-22.1 mm) and distensibility (1-55 mm(2)/mmHg) of the pylorus. Symptoms of early satiety and postprandial fullness were inversely correlated with pyloric sphincter diameter and CSA. No significant difference was seen between diabetic and idiopathic gastroparetics. EndoFLIP is a novel technique that can be used to assess pyloric physiologic characteristics. Early satiety and postprandial fullness were inversely correlated with diameter and CSA of the pyloric sphincter. No significant differences were seen comparing diabetic and idiopathic gastroparetics. This technology may be of benefit to help select patients with pyloric sphincter abnormalities.

Accuracy and Reproducibility of High-definition Anorectal Manometry and Pressure Topography Analyses in Healthy Subjects

High-definition anorectal manometry (HDAM-3D) provides a topographic and 3-dimensional profile of anorectal pressure. We assessed anorectal sensorimotor function and the reproducibility of measurements made with HDAM-3D in healthy adults, and the accuracy of data analysis by its software. Anal sphincter pressures and rectal sensory thresholds were measured in 78 healthy subjects via placement of a 10-mm rigid probe, with 256 circumferentially arrayed pressure sensors, and a balloon in the rectum. The bearing down maneuver was assessed in a subset of 18 subjects. We compared data analyzed by an expert with findings from automated software analysis. Measurements made in a subset of 16 subjects, 2 weeks apart, were compared to determine reproducibility. Resting, squeezing, and sustained squeezing pressures were significantly higher in men than in women (P < .05); other parameters were similar. Desire and urgency to defecate were similar between men and women, but the maximal tolerable volume was significantly lower in women (P < .05). Older women (>50 years) had significantly lower resting (P < .01) and sustained squeeze pressures (P < .04). Dyssynergic patterns of defecation were observed in 12 of 18 subjects (67%) who attempted to defecate without the 60-mL rectal balloon distention and in 6 of 18 subjects (33%) with the 60-mL rectal balloon distention. Test-retest values correlated (r= 0.81), as did analyses made by an expert vs software analyses of data (r= 0.99). On the basis of HDAM-3D measurements in healthy adults, anal sphincter pressures are higher in men than in women, but sensory and other parameters are similar; older subjects have weaker sphincters. Many people were found to have dyssynergic patterns of defecation, which could be related to the probe or other technical issues, so this technique may not be suitable for assessing defecation patterns. Measurements made by HDAM-3D are reproducible, and data can be accurately analyzed by its software.

Brain regions involved in moxibustion-induced analgesia in irritable bowel syndrome with diarrhea: a functional magnetic resonance imaging study.

BackgroundMoxibustion is one of the most commonly used therapies in acupuncture practice, and is demonstrated to be beneficial for patients with diarrhea from irritable bowel syndrome (D-IBS). But its mechanism remains unclear. Because visceral hypersensitivity in IBS patients has been documented by evaluation of perceived stimulations through functional magnetic resonance imaging (fMRI) studies, we focused on observing brain imaging changes in D-IBS patients during rectal balloon distention before and after moxibustion in order to reveal its possible central mechanism and further evaluate its effect.MethodsThis clinical trial is registered under the number: ChiCTR-TRC-10000887. Eighty D-IBS patients were randomly divided into a moxibustion and sham moxibustion group (control group) for a 4-week treatment. Fifteen patients in moxibustion group and thirteen patients in control group completed two fMRI scans during a 50 and 100 ml rectal balloon distention before and after treatment. Rectal pain were obtained with a scan test. Birmingham IBS Symptom Scale and IBS Quality of Life (QOL) Scale were used to evaluate therapeutic effect.ResultsAfter treatment, the decrease in Birmingham IBS Symptom Scale and IBS QOL Scale scores in moxibustion group was significantly greater than that of control group (P < 0.01). The defecation urge threshold and the pain perception threshold of moxibustion group was also significantly higher after treatment than that of control group (P < 0.01). The decrease in pain score during the 100 ml rectal balloon distention in moxibustion group was significantly greater than that of control group (P < 0.05). There was no definite activated center during the 50 ml rectal distention in either group before treatment. After treatment, the prefrontal cortex (PFC) was affected in moxibustion group, while the PFC and the anterior cingulated cortex (ACC) were affected in control group. During the 100 ml distention before treatment in both groups, the PFC and ACC were activated. After treatment, they disappeared in moxibustion group but remained in control group.ConclusionsMoxibustion can improve symptoms and quality of life in D-IBS patients. It can also decrease rectal sensitivity. The activation of PFC and ACC during a 100 ml rectal distention disappeared after moxibustion treatment.

The influence of extraversion on brain activity at baseline and during the experience and expectation of visceral pain

Eysenck proposed a ‘trait theory’ of personality, the dimensions of which encompass numerous individual qualities. Whilst the influence of neuroticism on the brain processing of pain is well described, the role of extraversion, to date, has not been systematically investigated. Our aim was to address this knowledge gap using functional magnetic resonance imaging (fMRI).Extraversion was measured in 33 healthy volunteers (17 males, mean age 29years [range 20–53]) using the Eysenck Personality Questionnaire. fMRI data were acquired using a 3T MRI scanner during rest, pain anticipation, and painful oesophageal balloon distention. The effect of extraversion on fMRI responses was determined.Extraversion scores varied (range 6–22) and did not influence pain threshold or rating. High extraversion was associated with significantly greater activity in the left cuneus during rest (p⩽0.001), and the right insula during both anticipation (p⩽0.0002) and pain (p⩽0.0008). Low extraversion was associated with significantly greater brain activity in the bilateral precuneus, bilateral lingual gyrus, right inferior temporal gyrus, left fusiform gyrus and left superior parietal lobule during pain anticipation (all p⩽0.0001).These results suggest that extraversion is associated with differences in the brain processing of visceral pain. Future studies of visceral pain, using fMRI, should control for extraversion.

Methylglyoxal induces systemic symptoms of irritable bowel syndrome.

Patients with irritable bowel syndrome (IBS) show a wide range of symptoms including diarrhea, abdominal pain, changes in bowel habits, nausea, vomiting, headache, anxiety, depression and cognitive impairment. Methylglyoxal has been proved to be a potential toxic metabolite produced by intestinal bacteria. The present study was aimed at investigating the correlation between methylglyoxal and irritable bowel syndrome. Rats were treated with an enema infusion of methylglyoxal. Fecal water content, visceral sensitivity, behavioral tests and serum 5-hydroxytryptamine (5-HT) were assessed after methylglyoxal exposure. Our data showed that fecal water content was significantly higher than controls after methylglyoxal exposure except that of 30 mM group. Threshold volumes on balloon distension decreased in the treatment groups. All exposed rats showed obvious head scratching and grooming behavior and a decrease in sucrose preference. The serum 5-HT values were increased in 30, 60, 90 mM groups and decreased in 150 mM group. Our findings suggested that methylglyoxal could induce diarrhea, visceral hypersensitivity, headache as well as depression-like behaviors in rats, and might be the key role in triggering systemic symptoms of IBS.