Gastrointestinal Myoelectric Activity Research Articles

A novel pilot study to evaluate the efficacy and safety of a wireless patch system in patients with chronic nausea and vomiting.

Gastric sensorimotor disorders (functional dyspepsia [FD] and gastroparesis [GP]) are prevalent and burdensome. Prolonged ambulatory recording using a wireless patch may provide novel information in these patients. Consecutive adult patients (age ≥ 18 years) referred for gastric emptying scintigraphy (GES) were eligible for study inclusion. Patients were excluded if they had prior foregut surgery; were taking opioids or other medications known to affect gastric emptying; had a HgbA1C > 10; or were recently hospitalized. Three wireless motility patches were applied to the skin prior to GES. Patients wore the patches for 6 days while recording meals, symptoms, and bowel movements using an iPhone app. Twenty-three consecutive adults (87% women; mean age = 43.9 years; mean BMI = 26.7 kg/m2) were enrolled. A gastric histogram revealed three levels of gastric myoelectric activity: weak, moderate, and strong. Patients with delayed gastric emptying at 4 h had weak gastric myoelectrical activity. Patients with nausea and vomiting had strong intestinal activity. Those with FD had weak gastric and intestinal myoelectric activity, and a weak meal response in the stomach, intestine, and colon compared to those with nausea alone or vomiting alone. Patients with FD, and those with delayed gastric emptying, had unique gastrointestinal myoelectrical activity patterns. Reduced postprandial pan-intestinal myoelectric activity may explain the symptoms of FD in some patients. Recording gastrointestinal activity over a prolonged period in the outpatient setting has the potential to identify unique pathophysiologic patterns and meal-related activity that distinguishes patients with distinct gastric sensorimotor disease states.

Gastrointestinal Myoelectrical Activity (GIMA) Biomarker for Noninvasive Diagnosis of Endometriosis.

Background/Objectives: Endometriosis represents substantial direct and indirect healthcare costs impacted by an absence of uniformly accurate, non-invasive diagnostic tools. We endeavored to demonstrate gastrointestinal myoelectrical activity (GIMA) biomarkers, unique to endometriosis, will allow non-invasive, uniformly accurate diagnosis or exclusion of endometriosis. Methods: Prospective open-label comparative study of 154 patients, age ≥ 18, with or without diagnosed endometriosis. Population included 62 non-endometriosis controls (Cohort 1), 43 subjects with surgically/histologically confirmed endometriosis (Cohort 2), and 49 subjects with abdominal pain and negative imaging (Cohort 3). Non-invasive electroviscerography (EVG) recorded GIMA biomarkers from three abdominal electrodes before and 30 min post water load protocol. Cohort 2 had postoperative EVG and Cohort 3 had preoperative EVG. Calculated specificity, sensitivity, negative predictive value (NPV), positive predictive value (PPV), and predictive probability or C-statistic used univariate, multivariate, linear, and logistical regression analyses of the area under the curve (AUC) at all frequency and time points, including age and pain covariants. Results: The non-endometriosis cohort differed significantly from the endometriosis cohorts (p < 0.001) for median (IQR) and AUC percent frequency distribution of power at baseline, 10 min, 20 min, and 30 min post water load at all frequency ranges: 15-20 cpm, 30-40 cpm, and 40-50 cpm. The endometriosis cohorts were statistically similar (p > 0.05). GIMA biomarker threshold scoring demonstrated 95%/91% sensitivity and PPV, 96%/95% specificity and NPV, and a C-statistic of >99%/98%, respectively, for age subsets. GIMA biomarkers in Cohort 3 predicted 47/49 subjects positive and 2/49 negative for endometriosis, confirmed surgically. Hormonal therapy, surgical stage, nor pain score affected diagnostic accuracy. Conclusions: EVG with GIMA biomarker detection distinguished participants with and without endometriosis based upon endometriosis-specific GIMA biomarkers threshold scoring.

Exploring the role of ghrelin and des-acyl ghrelin in chemotherapy-induced nausea and vomiting

Ghrelin and its mimetics have been shown to reduce cisplatin-induced emesis in preclinical studies using ferrets and shrews. This study investigated the effectiveness of ghrelin and des-acyl ghrelin (DAG) in antagonizing cisplatin-induced emesis and physiological changes indicative of nausea in Suncus murinus. Animals implanted with radiotelemetry devices were administered ghrelin (0.2, 1.0, and 5.0 μg/day), DAG (0.2, 1.0, and 5.0 μg/day), or saline (14 μL/day) intracerebroventricularly 4 days before and 3 days after treatment with cisplatin (30 mg/kg). At the end, the anti-apoptotic potentials of ghrelin and DAG were assessed by measuring Bax expression and cytochrome C activity. Neurotransmitter changes in the brain were evaluated using liquid chromatography–mass spectrometry analysis. Ghrelin and DAG reduced cisplatin-induced emesis in the delayed (24–72 h) but not the acute phase (0–24 h) of emesis. Ghrelin also partially reversed the inhibitory effects of cisplatin on food intake without affecting gastrointestinal myoelectrical activity or causing hypothermia; however, ghrelin or DAG did not prevent these effects. Ghrelin and DAG could attenuate the cisplatin-induced upregulation of Bax and cytochrome C in the ileum. Cisplatin dysregulated neurotransmitter levels in the frontal cortex, amygdala, thalamus, hypothalamus, and brainstem, and this was partially restored by low doses of ghrelin and DAG. Our findings suggest that ghrelin and DAG exhibit protective effects against cisplatin-induced delayed emesis. The underlying antiemetic mechanism may involve GHSR and/or unspecified pathways that modulate the neurotransmitters involved in emesis control in the brain and an action to attenuate apoptosis in the gastrointestinal tract.

Potential value of gastrointestinal myoelectrical activity in the diagnosis of anxiety-depression disorder: a population-based study

BackgroundDepression and anxiety are frequently coexisted mental illness. The lack of solid objective diagnostic criteria has led to a high rate of suicide. The brain-gut axis bridges the gastrointestinal system with neuropsychiatric disorders. However, it is still not possible to reflect mental disease with gastrointestinal information. The study aimed to explore the auxiliary diagnostic value of gastrointestinal myoelectrical activity in anxiety-depression disorders (ADD) without gastrointestinal disturbance.MethodsA natural population cohort from 3 districts in Western China were established. The Patient Health Questionnaire-9 and the Generalized Anxiety Disorder-7 were used to assess ADD. Gastrointestinal myoelectrical activity of ADD were measured by multi-channel cutaneous electrogastroenterogram (EGEG). Then the parameters of EGEG between ADD and healthy controls were analyzed.ResultsThe average amplitude and response area of intestinal channel in ADD were significantly lower than those of controls (153.49 ± 78.69 vs. 179.83 ± 103.90, 57.27 ± 29.05 vs. 67.70 ± 38.32), which were shown to be protective factors for ADD (OR = 0.944 and 0.844, respectively). Further, the scale item scores related to the core symptoms of anxiety and depression were also associated with these two channels (p < 0.05), and the gastrointestinal electrical signals of ADD are significantly changed in the elderly compared to the young adults.ConclusionsThe intestinal myoelectrical activity has a certain auxiliary diagnostic value in psychiatric disorders and is expected to provide objective reference for the diagnosis of anxiety and depression.

Prediction of gastroesophageal reflux episodes by smooth muscle electromyography: A translational study in rats and adolescents

AimsOur aim was to measure the myoelectric modifications during gastric acid secretion along with the gastric pH in a rat model and to detect the gastrointestinal (GI) myoelectric changes in adolescents suffering from gastroesophageal reflux disease (GERD) along with the esophageal pH measurement. Main methodsIn anesthetized rats, gastric acid secretion was initiated with intragastric histamine (50 mg/kg), and gastric pH, GI myoelectric activity and mechanical GI contractions were measured with intragastric pH electrode, subcutaneously implanted smooth muscle electromyography (SMEMG) electrodes and organ implanted strain gauges, respectively. In the clinical study, esophageal pH and GI myoelectric activity were measured in adolescents suffering from GERD with intraesophageal pH electrode and SMEMG electrodes placed on the abdominal surface, respectively. The SMEMG records were analyzed by fast Fourier transformation (FFT) and power spectrum density maximum (PsDmax) values were calculated for the GI segments. Key findingsIn rats, histamine initiated an immediate increase in gastric PsDmax, which preceded the significant reduction in gastric pH by 75 min. The myoelectric change was independent of mechanical GI contractions. In adolescents, the GERD episodes were preceded by a significant increase in gastric PsDmax 45 min earlier. These changes were independent of motion or meals. SignificanceIncreased gastric myoelectric activity during histamine stimulation or GERD might be linked to the enhanced activity of the gastric proton pump, indicating a link between gastric acid secretion and GERD episodes. It is supposed that SMEMG might be a tool for predicting forthcoming reflux episodes in GERD.

Prediction of gastrointestinal functional state based on myoelectric recordings utilizing a deep neural network architecture.

Functional and motility-related gastrointestinal (GI) disorders affect nearly 40% percent of the population. Disturbances of GI myoelectric activity have been proposed to play a significant role in these disorders. A significant barrier to usage of these signals in diagnosis and treatment is the lack of consistent relationships between GI myoelectric features and function. A potential cause of this issue is the use of arbitrary classification criteria, such as percentage of power in tachygastric and bradygastric frequency bands. Here we applied automatic feature extraction using a deep neural network architecture on GI myoelectric signals from free-moving ferrets. For each animal, we recorded during baseline control and feeding conditions lasting for 1 h. Data were trained on a 1-dimensional residual convolutional network, followed by a fully connected layer, with a decision based on a sigmoidal output. For this 2-class problem, accuracy was 90%, sensitivity (feeding detection) was 90%, and specificity (baseline detection) was 89%. By comparison, approaches using hand-crafted features (e.g., SVM, random forest, and logistic regression) produced an accuracy from 54% to 82%, sensitivity from 46% to 84% and specificity from 66% to 80%. These results suggest that automatic feature extraction and deep neural networks could be useful to assess GI function for comparing baseline to an active functional GI state, such as feeding. In future testing, the current approach could be applied to determine normal and disease-related GI myoelectric patterns to diagnosis and assess patients with GI disease.

Risk assessment model for sleep disturbance based on gastrointestinal myoelectrical activity in middle-aged and elderly people.

Sleep disturbance has become a considerable factor affecting the quality of life for middle-aged and elderly people; however, there are still many obstacles to screening sleep disturbance for those people. Given the growing awareness of the association between gastrointestinal function and sleep disturbance, our study aims to predict the risk of sleep disturbance using gastrointestinal electrophysiological signals. The Pittsburgh Sleep Quality Index and gastrointestinal electrophysiological signals of 914 participants in western China were used to establish the model. Demographic characteristics and routine blood test were collected as covariates. Participants were randomly assigned into two sets with a 7:3 ratio for training and validation. In the training set, the least absolute shrinkage and selection operator (LASSO) regression and stepwise logistic regression were used, respectively for variables selection and optimization. To assess the model performance, receiver operator characteristic (ROC) curve, calibration curve and decision curve analysis (DCA) were utilized. Then, validation was performed. Thirteen predictors were chosen from 46 variables by LASSO regression. Then, age, gender, percentage of normal slow wave and electrical spreading rate on the pre-meal gastric channel, dominant power ratio on the post-meal gastric channel, coupling percent and dominant frequency on the post-meal intestinal channel were the seven predictors reserved by logistic regression. The area under ROC curve was 0.65 in the training set and 0.63 in the validation set, both exhibited moderate predictive ability. Furthermore, by overlapping the DCA results of two data-sets, there might be clinical net benefit if 0.35 was used as reference threshold for high risk of sleep disturbance. The model performs a worthy predictive potency for sleep disturbance, which not only provides clinical evidence for the association of gastrointestinal function with sleep disturbance, but also can be considered as an auxiliary assessment for screening sleep disturbance.

Development of a Gastrointestinal-Myoelectrical-Activity-Based Nomogram Model for Predicting the Risk of Mild Cognitive Impairment.

Mild cognitive impairment (MCI) is the prodromal stage and an important risk factor of Alzheimer's disease (AD). Interventions at the MCI stage are significant in reducing the occurrence of AD. However, there are still many obstacles to the screening of MCI, resulting in a large number of patients going undetected. Given the strong correlation between gastrointestinal function and neuropsychiatric disorders, the aim of this study is to develop a risk prediction model for MCI based on gastrointestinal myoelectrical activity. The Mini-Mental State Examination and electrogastroenterography were applied to 886 participants in western China. All participants were randomly assigned to the training and validation sets in a ratio of 7:3. In the training set, risk variables were screened using LASSO regression and logistic regression, and risk prediction models were built based on nomogram and decision curve analysis, then validation was performed. Eight predictors were selected in the training set, including four electrogastroenterography parameters (rhythm disturbance, dominant frequency and dominant power ratio of gastric channel after meal, and time difference of intestinal channel after meal). The area under the ROC curve for the prediction model was 0.74 in the training set and 0.75 in the validation set, both of which exhibited great prediction ability. Furthermore, decision curve analysis displayed that the net benefit was more desirable when the risk thresholds ranged from 15% to 35%, indicating that the nomogram was clinically usable. The model based on gastrointestinal myoelectrical activity has great significance in predicting the risk of MCI and is expected to be an alternative to scales assessment.

AI-Derived Threshold Score of Intraabdominal Myoelectrical Activity Predicts Presence and Stage of Endometriosis with 100% Accuracy

Study Objective 1) Demonstrate non-invasive cutaneous Electroviscerography (EVG)-detected abnormal gastrointestinal myoelectrical activity (GMA) has 100% accuracy diagnosing endometriosis. 2) Demonstrate GMA-based artificial intelligence (AI)-derived formulae detects endometriosis regardless of hormonal suppression, surgical stage or symptoms. Design Prospective open-labeled study. Setting Clinical center for women's healthcare. Patients or Participants 50 women ages 17-45 with chronic abdominal pain, negative CT or MRI, and gastrointestinal endoscopy, scheduled for laparoscopy. Interventions Baseline EVG w/water load satiety test(WLST) and pain scores, followed by diagnostic laparoscopic surgery w/biopsy. Measurements and Main Results Response to EVG WLST identified specifically elevated GMA frequencies of 15-20(9.5 vs 2.2, p<0.001), 30-40(3.1 vs 0.8, p<0.001) and 50-60(1.1 vs 0.5,p<0.05) compared to known population normals and disease free subjects with abdominal pain. GMA-derived 2 stage Ai-determined threshold (AIET) was calculated to be >0.5, using linear regression of area under curve on first pass and age and pain scores in the second pass, demonstrated 100% selectivity and 100% specificity, respectively. All subjects exceeded AIET and had ASRM stages 1-4 at laparoscopy. AIET scores ranged 0.52 to 8.9, and escalated according to advancing surgical grade. Hormonal suppression did not affect diagnosis. Conclusion Endometriosis-specific abnormalities of GMA post-WLST predicts surgically detected endometriosis w/100% accuracy. AI GMA-derived threshold detects endometriosis with 100% sensitivity and specificity. Hormonal suppression, symptoms and surgical grade of endometriosis did not affect test accuracy. Variations in Ai-derived threshold scores may predict surgical stage of endometriosis. EVG represents an ideal test for the detection and screening of endometriosis. 1) Demonstrate non-invasive cutaneous Electroviscerography (EVG)-detected abnormal gastrointestinal myoelectrical activity (GMA) has 100% accuracy diagnosing endometriosis. 2) Demonstrate GMA-based artificial intelligence (AI)-derived formulae detects endometriosis regardless of hormonal suppression, surgical stage or symptoms. Prospective open-labeled study. Clinical center for women's healthcare. 50 women ages 17-45 with chronic abdominal pain, negative CT or MRI, and gastrointestinal endoscopy, scheduled for laparoscopy. Baseline EVG w/water load satiety test(WLST) and pain scores, followed by diagnostic laparoscopic surgery w/biopsy. Response to EVG WLST identified specifically elevated GMA frequencies of 15-20(9.5 vs 2.2, p<0.001), 30-40(3.1 vs 0.8, p<0.001) and 50-60(1.1 vs 0.5,p<0.05) compared to known population normals and disease free subjects with abdominal pain. GMA-derived 2 stage Ai-determined threshold (AIET) was calculated to be >0.5, using linear regression of area under curve on first pass and age and pain scores in the second pass, demonstrated 100% selectivity and 100% specificity, respectively. All subjects exceeded AIET and had ASRM stages 1-4 at laparoscopy. AIET scores ranged 0.52 to 8.9, and escalated according to advancing surgical grade. Hormonal suppression did not affect diagnosis. Endometriosis-specific abnormalities of GMA post-WLST predicts surgically detected endometriosis w/100% accuracy. AI GMA-derived threshold detects endometriosis with 100% sensitivity and specificity. Hormonal suppression, symptoms and surgical grade of endometriosis did not affect test accuracy. Variations in Ai-derived threshold scores may predict surgical stage of endometriosis. EVG represents an ideal test for the detection and screening of endometriosis.

Deciphering Stomach Myoelectrical Slow Wave Conduction Patterns via Confocal Imaging of Gastric Pacemaker Cells and Fractal Geometry.

Interstitial Cells of Cajal (ICC) are specialized gastrointestinal (GI) pacemaker cells that generate and actively propagate slow waves of depolarization (SWs) of the muscularis propria. SWs regulate the motility of the GI tract necessary for digestion, absorption of nutrients, and elimination of waste. Within the gastric wall, there are three main inter-connected layers of ICC networks: longitudinal muscle ICC (ICC-LM), myenteric plexus ICC (ICC-MP) & circumferential muscle (ICC-CM). Fractal structural parameters such as Fractal Dimension (FD), Lacunarity and Succolarity, have many advantages over physically-based parameters when it comes to characterizing the complex architectures of ICC networks. The analysis of networks of ICC throughout the proximal and distal murine gastric antrum with the FD and Lacunarity metrics was previously performed. Although the application of Succolarity is relatively nascent compared to the FD and Lacunarity; nevertheless, numerous studies have demonstrated the capability of this fractal measure to extract information from images associated with flow by which neither the FD nor Lacunarity are capable of discerning. In this study, Succolarity analysis of ICC-MP and ICC-CM networks were performed with confocal images taken across the proximal and distal murine antrum. Our findings demonstrated the Succolarity of ICC-MP and ICC-CM varied with directions and antral regions. The Succolarity of ICC-MP did not vary considerably with direction, however, Succolarity was higher in the aboral direction with 0.2113 ±0.1589, and 0.0637 ±0.0822 in the proximal and distal antrum, respectively. The overall Succolarity of ICC-MP was significantly higher than that of ICC-CM in the proximal antrum ( 0.1580±0.1325 vs [Formula: see text]) and in the distal antrum ( 0.0449 ±0.0409 vs [Formula: see text]). Clinical Relevance-Modeling SWs conduction patterns via image analysis of detailed ICC networks help to facilitate an improved understanding of the mechanisms underpinning GI myoelectric activity and the diseases associated with its dysfunction.

Gastrointestinal Myoelectric Measurements via Simultaneous External and Internal Electrodes in Pigs

IntroductionCurrently, there is no accurate noninvasive measurement system to diagnose gastrointestinal (GI) motility disorders. Wireless skin patches have been introduced to provide an accurate noninvasive measurement of GI myoelectric activity which is essential for developing neuro-stimulation devices to treat GI motility disorders. The aim of this study is to compare the external and internal electrical signal measurements in ambulatory pigs. MethodsYucatan pigs underwent placement of internal electrodes on the stomach, small intestine, and colon. Wires were brought through the abdominal wall. Signals were collected by a wireless receptor. Four external patches were placed on the abdominal skin to record the signals simultaneously. Pigs were kept for 6 d while the sensors were continuously recording the data from both systems. ResultsInternal sensors detected rich signals from each organ. The stomach had a dominant frequency that ranged from 4 to 4.5 cpm, with occasional higher frequencies at 2, 3 and 4 times that. Small intestine signals had their primary energy in the 12-15 cpm range. Colon signals primarily displayed a dominant broad peak in the 4-6 cpm region. External skin patches detected a substantial fraction of the activities measured by the internal electrodes. A clear congruence in the frequency spectrum was observed between the internal and external readings. ConclusionsInternally measured myoelectrical signals confirmed different patterns of rhythmic activity of the stomach, small intestine, and colon. Skin patches provided GI myoelectric measurement with a range of frequencies that could be useful in the diagnosis and treatment of motility disorders.

Impact of Isoflurane Anesthesia on Gastrointestinal Myoelectric Recordings: A Comparative Analysis of Awake and Anesthetized States in Ferrets

Gastrointestinal (GI) slow wave recordings have a long history of investigation but currently limited use in clinical diagnosis and treatment. GI myoelectric activity could potentially play a role in the treatment of functional and motility‐related GI diseases and obesity by providing biomarkers of GI function or a target for clinical interventions. Significant issues, however, hinder our understanding of these signals, including: (1) use of abdominal surface recordings with low spatio‐temporal resolution; (2) typical use of few signaling features, such as deviations from dominant slow wave frequencies; and, (3) lack of defined relationships to GI functions, for example, muscle contraction and movement of luminal contents. Thus, there is a critical need to determine the value of GI myoelectric signals for clinical application and to assess stability of these signals in different testing conditions. As a first step, we tested the hypothesis that gastric myoelectric activity differs between awake and anesthetized states. Acute surgical preparations with open abdomen GI recordings are potentially an ideal setting to investigate slow wave physiology, but it is unknown how anesthesia affects gastric myoelectric signals. Here, we chronically implanted 5 ferrets with four gastric serosal surface electrodes, from fundus to antrum. Following recovery, we conducted electrophysiological recordings under awake and isoflurane anesthesia (from 1 to 3%) conditions. By comparing 95% confidence intervals for the Welch's overlapped segment averaging power spectral densities (PSD) estimated from myoelectric recordings in awake and anesthetized states, we observed statistically significant reductions in power in the anesthetized state (p&lt;0.01 for each of 18 electrodes across animals). The reductions in area under PSD curves were over 90% for 14 electrodes, and ranged between 41% and 88% for 4 electrodes. Suppression did not occur for one electrode, and another was discarded due to corrupted recordings. Moreover, signal power after exposure to isoflurane anesthesia was concentrated in narrow frequency bands, with marked bimodalities in 17 electrodes, in contrast to a more uniform power distribution in the awake state. The time courses of PSDs were also markedly different in awake and anesthetized states, with gastric activity presenting little variation over time in the latter, and substantial variability in the former, which may be associated with behavioral movement. Indeed, in the awake state, one animal had distinct and contiguous long epochs of movement (e.g., grooming, standing) and rest, which correlated with high and low power respectively (p&lt;0.01 for 3 channels; p&lt;0.05 for 1 channel in the animal). These data reveal potential changes in gastric myoelectric activity under anesthesia, which could impact post‐operative recovery. This study also provides insight into the changes in gastric myoelectric activity during anesthesia and reinforces the need to conduct recordings in the awake state.

Non-invasive smooth muscle electromyography (SMEMG) as a novel monitoring technology of the gastrointestinal tract of awake, free-moving pigs-A pilot study.

There are several mathematical models and measurements to determine the efficiency of the digestibility of different feedstuffs. However, there is lack of information regarding the direct methods or measurement techniques used to analyse the physical response of the different parts of the gastrointestinal tract (GIT) of growing pigs to different diets. Smooth muscle electromyography (SMEMG) is a non-invasive method for the measurement of gastrointestinal myoelectrical activity. In the present study, SMEMG methodology has been adapted from laboratory rats to pigs, and the effects of feedstuffs with control (CTR) or experimentally increased (EXP) amounts of fibre were investigated on gastrointestinal tract motility. Nine barrow pigs ((Danish Landrace × Danish Yorkshire) × Danish Duroc) were used (30 ± 3 kg), and their CTR and EXP feedstuffs contained 29 and 49 g/kg crude fibre (CF), respectively. Myoelectric activities of the stomach, ileum and caecum were detected in the awake pigs by a pair of electrodes. The recorded myoelectric signals were analysed with fast Fourier transformation (FFT), and the spectra were expressed in GIT section-specific cycles per minutes (cpm) values and the maximum power spectrum density (PsDmax). A significant increase (P < 0.001) was observed in the value of the PsDmax of the small intestine (20-25 cpm) as a consequence of the EXP diet. The PsDmax values of the stomach (3-5 cpm) and large intestine (1-3 cpm) did not show any significant change in pigs fed the EXP diet. As a direct and non-invasive method, SMEMG is suitable for the rapid evaluation of the effects of diets with different fibre contents on the GIT of non-anaesthetised, free-moving pigs.

Saussurea Lappa Modulates Gastrointestinal Motility, Motilin and Cholecystokinin Expression in Ulcer Rats

AIM : To investigate effects of Saussurea lappa (S.lappa) on rat chronic duodenal ulcer induced by ethylic acid and the underlying mechanisms. METHODS : Wistar rat chronic duodenal ulcer was patterned according to Okabe model while two pairs of bipolar stainless steel electrodes were implanted onto the serosal layer of gastrointestinal tract. Then, the rats were treated with water, Omeprazole, diverse-dose S.lappa for 10 days. Gastrointestinal motility, intestine propulsion and duodenal ulcer crater were detected. Expressions of cholecystokinin and motilin in duodenum were detected by immunohistochemistry (IHC). Motilin serum level was measured with enzyme-linked immunosorbent assay (ELISA). RESULT ：Duodenal ulcer group rats had obvious disorders of gastrointestinal motility and brain-gut peptide secretion, including gastrointestinal myoelectric activity inhibition, migrating myoelectric complex (MMC) interruption, intestinal propulsion slowdown, cholecystokinin and motilin secretion decrease. Similarity to Omeprazole, S.lappa accelerated the coalescence of ethylic acid–induced duodenal ulcer significantly (p<0.01, vs model group), but no obvious dose-dependent effect was found. S.lappa also improved gastrointestinal myoelectric activity and accelerated intestinal propulsion. Furthermore, S.lappa could increase the expression levels of cholecystokinin and motilin in duodenum and increase motilin level in serum. CONCLUSION ：S.lappa can accelerate the coalescence of chronic duodenal ulcer, and increase gastrointestinal myoelectric activity and the expression of cholecystokinin and motilin in duodenum.

Involvement of neuronal nitric oxide synthase (nNOS) in the regulation of migrating motor complex (MMC) in sheep

The objectives of this study were to evaluate the role of nitric oxide (NO) synthase isoforms (nNOS, eNOS, and iNOS) in the regulation of the migrating motor complex (MMC) in sheep using electromyography and their expression in the gastrointestinal (GI) tract by Western blot (WB) and immunohistochemistry. Intravenous administration of L-NAME or the nNOS inhibitor 7-nitroindazole (7-NI) decreased the MMC interval. Myoelectric activity of intestinal phase II was increased, whereas antral activity was reduced. These effects were blocked by L-arginine. Inhibitors of either iNOS (aminoguanidine and S-methylisothiourea) or eNOS (L-NIO) were ineffective. The NO donor sodium nitroprusside decreased GI myoelectric activity, inhibited the MMC pattern, and prevented the effects induced by L-NAME and 7-NI in the intestine. Intracerebroventricular administration of these agents did not modify GI motility. In the rumen, abomasal antrum, duodenum, and jejunum, WB showed three bands at about 155, 145, and 135kDa corresponding to nNOS, and a 140-kDa band (eNOS); however iNOS was not detected. Positive nNOS immunostaining was observed in neurons of the myenteric and submucous plexus of all GI tissues, while eNOS was found in the endothelial cells, ruminal and intestinal epithelium, as well as in some enteric neurons and in endocrine-like cells of the duodenal Brunner's glands. In contrast, only weak iNOS immunoreactivity was found in ruminal epithelium. Taken together, our results suggest that NO, synthesized at a peripheral level by nNOS, is tonically inhibiting the MMC pattern and intestinal motility in sheep.

Effect of daily loperamide administration on gastrointestinal myoelectric activity

The objective of this study was to determine the effect of daily administration of loperamide on gastrointestinal myoelectric activity. Six dogs were randomly administered three regimens–placebo, low dose loperamide (0.10–0.15 mg/kg/day, p.o.), and high dose loperamide (0.30–0.36 mg/kg/day, p.o.)–for one week each. Using surgically implanted bipolar electrodes, gastrointestinal myoelectric activity was recorded on at least 2 fed and 2 fasted experimental days for each regimen. In the fasted state, low dose loperamide decreased MMC cycle length, initiated intestinal amyogenesia in 40% of experiments, but did not induce vomiting. High-dose loperamide in the fasted state did not change MMC cycle length, but induced vomiting in 50% of experiments and initiated intestinal amyogenesia in 43% of experiments. The rate of occurrence of the myoelectric carrelates of giant migrating contractions (GMCs) and retrograde giant contractions (RGCs) increased with loperamide administration at both doses, as did the rate of occurrence of fed state MMCs. We conclude that daily oral administration of loperamide results in: (1) a dose-dependent effect on MMC cycle length; (2) intestinal amyogenesia; (3) an increase in frequency of vomiting at higher doses; and (4) an increase in incidence of GMCs and RGCs.

Effects and probable mechanisms of electroacupuncture at the Zusanli point on upper gastrointestinal motility in rabbits

The purposes of this study were to investigate the regulative effect of acupuncture on gastrointestinal motility in rabbits and to explore the probable mechanism of electroacupuncture. The experiment was performed on 30 rabbits implanted with three pairs of electrodes, which were equally divided into three groups: the control group, the Zusanli group, and the non-acupuncture point group. The gastrointestinal myoelectrical activity of each conscious rabbit was recorded when acupuncture was applied. Motilin in plasma, cholecystokinin (CCK) in serum, the activity of acetylcholine esterase, nitric oxide synthase (NOS), and the vesicle of nerve endings in the stomach tissue and jejunum were investigated. It was found that electroacupuncture did not exert much influence on the slow wave of gastrointestinal myoelectrical activity, but significantly increased the number and amplitude of spikes. In the Zusanli group, the concentration of motilin and CCK was much higher at the post-acupuncture stage than at the pre-acupuncture stage. Electroacupuncture significantly enhanced the activity of acetylcholine esterase. Moreover, we found out that in the Zusanli group, the number of vesicles without granula was significantly fewer than in the control group. The activity of NOS was less in the Zusanli group than in the control group. Acupuncture may enhance the gastrointestinal myoelectrical activity of conscious rabbits. The cholinergic nerve, nitric oxide, motilin, and CCK may contribute to acupuncture mechanisms.

Roles of putative neurotransmitters in the regulation of gastric and intestinal slow waves in conscious dogs

Slow waves play an important role in controlling the frequency and propagation of gastrointestinal contractions. However, mechanisms involved in the modulation of slow wave activity in vivo are still unclear. In this study, the roles of different neurotransmitters in the regulation of gastrointestinal slow waves were investigated in conscious dogs. Female dogs implanted with electrodes in the stomach and the small bowel were used in a seven-session study. Gastrointestinal myoelectrical activity was recorded at baseline and after i.v. saline, atropine, atropine methyl nitrate, guanethidine, Nomega-nitro-L-arginine (L-NNA), ondansetron or naloxone. Both atropine and atropine methyl nitrate induced tachygastria, bradygastria and arrhythmia. No difference was noted in the effects between atropine and atropine methyl nitrate. L-NNA increased the dominant frequency of small-intestinal slow waves but had no effect on gastric slow waves. Guanethidine, ondansetron and naloxone did not affect the dominant frequency, power or percentage of normal gastrointestinal slow waves. Acetylcholine acting at muscarinic receptors seems to play an important role in the regulation of gastric slow waves. Nitric oxide may play a role in modulating intestinal slow waves but not gastric slow waves. Sympathetic pathways, 5-HT(3) receptors and opioid receptors (especially micro-opioid receptors) do not play a role in the regulation of gastric or intestinal slow waves under normal physiological conditions.

Effects of Sibutramine on Gastric Emptying, Intestinal Motility and Rectal Tone in Dogs

The aim of this study was to evaluate the effects of sibutramine on gastric emptying, small-bowel contractions, rectal tone and compliance, and gastrointestinal myoelectrical activity. The study was performed in 14 dogs. It was composed of three separate experiments: gastric emptying of liquids and gastrointestinal slow waves; small-bowel contractions; and rectal tone and rectal compliance. Each experiment included two sessions: a control session and a treatment session with sibutramine (5 mg/kg orally) administrated 2 h before the study. Sibutramine significantly accelerated liquid gastric emptying at 75 and 90 min after the meal but did not alter gastrointestinal slow waves. Gastric emptying at 75 and 90 min was 61.42 +/- 7.71 and 66.32 +/- 7.67% in the control session, and increased to 71.27 +/- 5.14 and 75.93 +/- 5.29% in the session with sibutramine (p < 0.05, vs. control). Sibutramine significantly inhibited postprandial small-bowel contractions. Sibutramine did not alter the rectal tone, but significantly increased rectal compliance. Sibutramine accelerates gastric emptying of liquids but inhibits small-bowel contractions. These findings suggest the peripheral mechanisms of sibutramine in reducing food intake and causing weight loss in obesity patients.

Relationship between entero-hepatic bile acid circulation and interdigestive migrating myoelectrical activity in rats

To investigate the effects of entero-hepatic bile acid circulation on the inter-digestive migrating myoelectrical complex (MMC) in rats. Thirty-two rats were divided into four groups. Three pairs of bipolar silver electrodes were chronically implanted in the antrum, duodenum and jejunum. Three groups of them were ligated around the upper part of common bile duct (CBD). The experiments were performed in conscious and fasting state. The gastrointestinal myoelectrical activity was recorded. Ursodeoxycholic acid (UDCA) and saline were then perfused into stomachs of two groups with CBD obstruction and the effects of them on the MMC were observed. A typical pattern of MMC was observed in normal fasting rats. MMC of antral and duodenal origin disappeared temporarily in earlier stage of CBD obstruction. While MMC of jejunum origin appeared. increased MMC cycle duration was seen after 4 d in rats with CBD obstruction. The MMC after CBD obstruction was characterized by an increased duration of phase II-like activity and decreased duration of phase I and III activity. Perfusion into stomachs with UDCA resulted in a shorter MMC cycle duration and a longer duration of phase III of duodenal origin compared to the normal group. Entero-hepatic bile acid circulation initiates inter-digestive MMC of duodenal origin.