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

AIM: To investigate the effects of entero-hepatic bile acid circulation on the inter-digestive migrating myoelectrical complex (MMC) in rats. METHODS: 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. RESULTS: 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 & 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. CONCLUSION: Entero-hepatic bile acid circulation initiates inter-digestive MMC of duodenal origin.     

Local inhibition of myoelectrical activity of human colon by loperamide

In order to study whether the antidiarrheal effects of loperamide are largely brought about by a local inhibition of the drug, we applied doses of 0.2 mg directly on the mucosa of the descending and sigmoid colon of 33 healthy volunteers. Loperamide decreased BER frequencies and reduced spike activity to 6.6±0.3% of time vs 11.3±0.7% in the control recorded from 3 cm aside and to 5.8±0.4% vs 12.7±0.9% in the descending and sigmoid colon, respectively. The same effects became apparent when spike activity was stimulated by neostigmine. Loperamide also reduced the occurrence of groups of spikes to 3.8±0.4/hr vs 10.3±0.6 and to 3.6±0.4/hr vs 14.6±0.7 in the descending and sigmoid colon, respectively. Groups of spikes are thought to be the equivalent of propulsive movements. Thus, loperamide is active locally and exhibits inhibitory effects on the motor activity of the colon. Clinical studies seem warranted to examine the effectiveness of loperamide enemas in motility disturbances of the anorectum.     

Large bowel myoelectrical activity in man.

The myoelectrical activity of human colon and rectum has been studied by three types of electrode in man--intraluminal (suction), serosal and cutaneous. The patterns obtained indicate a high degree of consistency between the methods and the value of surface electrodes is emphasized. Gradient along the large bowel of both frequency and percentage electrical activity have been observed and possible physiological roles are postulated for them. By correlating the features of regular electrical and corresponding regular motor waves an alteration in the myoelectrical pattern is observed in the region of the rectosigmoid junction.     

Colonic myoelectrical activity in IBS painless diarrhoea.

Colonic myoelectrical activity was recorded during 24 hours in 23 patients with painless diarrhoea and compared with a control group of 10 healthy subjects without digestive functional disorders. Diurnal fasting activity showed no significant difference in the total long spike bursts activity (LSB lasting greater than 7 seconds), but short spike bursts activity (SSB, lasting less than 7 seconds) was significantly lower (p less than 0.05) in diarrhoeal patients. A striking difference was observed in colonic response to eating, with an increased number of migrating long spike bursts (MLSB: mass movements) during the first postprandial hour in diarrhoeal patients (p less than 0.001), while short spike bursts (segmental activity) were almost absent in the rectosigmoid area. A marked decrease in the retrograde LSB activity was also observed in eight patients. During the night (from 2200 h to 0600 h) the number of migrating long spike bursts was increased in the diarrhoea group, but almost absent in controls (p less than 0.001). This study shows that colonic motor activity was altered in painless diarrhoea. These disturbances were not limited to the decreased SSB activity in the sigmoid, but involved the whole colon, with lower SSB activity and abnormal increase of migrating long spike bursts activity (MLSB) in postprandial and nocturnal periods.     

Colonic myoelectrical activity and propulsion in the dog

Electrical spike activity was recorded on the colon of the dog. The duration of the bursts of the spike was used to divide the spike activity into two different types: long and short spike bursts (LSB and SSB). LSBs lasted from 7 (ascending) to 37 sec (descending) and SSBs lasted about 1 sec, independent of the site. These measurements were applied to colons of colostomized dogs for which the colonic transit time was negatively correlated to the LSBs expressed as percent of the time. The effects of high- and low-residue diets were tested. Intake of large amounts of dry food was associated with an increase of the LSB activity. A meat diet was accompanied with an increase of the SSB activity. These results suggest a propulsive effect for the LSBs stimulated by large amounts of colonic contents while the SSB activity may reflect some degree of emptiness.     

不同状态糖尿病患者胃电活动的特点

目的: 观察不同状态糖尿病患者的胃电活动特征, 探讨糖尿病胃电紊乱的发展规律.方法: 2005-11/2006-05北京协和医院就诊的糖尿病患者54例, 根据糖尿病并发症及上消化道症状的有无分为3组: 无并发症及上消化道症状组, 有并发症而无明显上消化道症状组, 有并发症及明显上消化道症状组. 记录空腹30min和餐后60 min的体表胃电活动.结果: 糖尿病患者胃电节律异常发生率为74.1%. 餐前胃电活动表现为: 正常节律(46.3%)、胃动过缓(31.5%)、无节律(14.8%)、胃动过速(7.4%); 餐后胃电活动表现为: 胃动过缓(37%)、正常节律(35.2%)、无节律(20.4%)、胃动过速(7.4%). 有并发症及上消化道症状组的PR值显著高于无并发症及上消化道症状组(1.07±1.17 vs 0.93±0.14, P = 0.022).有并发症及上消化道症状者早饱症状的严重程度和PR值负相关( r = -0.535, P = 0.040).结论: 糖尿病患者胃电节律紊乱以胃动过缓最常见, 不同状态糖尿病患者的胃电活动存在差异.     

Gastric myoelectrical activity in patients with primary biliary cirrhosis

Objective  To examine gastric myoelectrical activity in patients with primary biliary cirrhosis (PBC). Materials and methods  The study comprised 11 female PBC patients (average age 53.4 years, range 43–70) and two aged-matched control groups: 11 (53.4 years, range 37–78) healthy women, and 10 female patients with chronic hepatitis C, CHC (53.9 years, range 35–66), who were examined prior to administration of an antiviral therapy. Every subject underwent an electrogastrographic recording comprising a 30-min interdigestive and a 120-min postprandial period. Results  Abnormal electrogastrograms, containing prolonged epochs of tachygastria in the postprandial phase were found in 2 out of 11 (18.2%) patients having both stage IV of the Scheuer’s PBC classification, as well as in 1 patient out of 10 (10%) with CHC at stage F2 according to the METAVIR fibrosis score. Conclusion  Electrogastrographic abnormalities do not seem to be pathognomonic for the PBC as a disease, but rather would be considered an unspecific sequel of a morbid liver affection.     

Effects of sennosides on colonic myoelectrical activity in man

The effects of sennosides on colonic myoelectrical activity were investigated in man. Spiking activity of the left and sigmoid colons was continuously recorded in seven constipated patients during two sessions from 5:00 PM to 9:00 am. Each patient received orally at 7:00 pm on two consecutive days 30 mg of sennosides one day (sequence S) and placebo on the other (sequence P) in a random fashion. A significant (P<0.05) increase of peristaltic activity (migrating long spike bursts or MLSBs) after sennosides was observed between 1:00 and 7:00 am,and a corresponding decrease between 7:00 and 9:00 am.No change was noted in total short spike burst (SSB) activity or in SSBs characteristic of the rectosigmoid area. This study indicates that the main modification of colonic motility induced by sennosides was a stimulation of propulsive activity (MLSBs), which occurred between 6–12 hr after oral administration, the delay required for orocecal transit and metabolism of the drug.This work was supported in part by INSERM grants 1300-05, 30, 39; in part by Fondation pour la Recherche Médicale; and in part by Institut National de la Recherche Agronomique.     

Altered migrating myoelectrical complex in an animal model of cholesterol gallstone disease: the effect of erythromycin

Background—The ground squirrel on a highcholesterol diet exhibits prolonged intestinal transit, a pathogeneticfactor in cholesterol gallstone formation.
Aims—To examine the effect of a high cholesteroldiet on the characteristics of the migrating myoelectrical complex(MMC) and the potential benefit of erythromycin.
Methods—Twenty four animals received either atrace (controls) or a 1% (high) cholesterol diet. After four weeks,five bipolar jejunal and terminal ileal electrodes were implanted.Seven days later, myoelectric activity was measured in conscious,fasted animals before and after treatment with erythromycin. Biliary lipid composition was assessed.
Results—Compared with controls, animals fed thehigh cholesterol diet exhibited a prolonged MMC cycle period (70 (6)versus 83 (3) minutes; p<0.05), whereas MMC migration velocity and the proportions of the MMC represented by phases I, II, and III were unchanged. Oral erythromycin significantly shortened the MMC cycle period in animals on the control and high cholesterol diet by 59% and54% respectively, and increased the proportion of the cycle periodoccupied by phase III of the MMC in both dietary groups. Gall bladderbile became saturated with cholesterol and crystals developed in nineof 12 animals on the high cholesterol diet; controls had none.
Conclusion—Animals fed a high cholesterol diethad a prolonged MMC cycle period. This, along with diminished gallbladder motility, impairs the enterohepatic cycling of bile salts and reduces their hepatic secretion, contributing to the formation ofabnormal bile. Erythromycin initiated more frequent cycling of the MMC.Its therapeutic value in cholesterol gallstone formation warrantsfurther evaluation.

Keywords:migrating myoelectrical complex; intestinal transit; cholesterol saturation index; gallstone disease; erythromycin

     

Enhanced postprandial gastric myoelectrical activity after moderate-intensity exercise

OBJECTIVE: The aim of this study was to investigate the change of postprandial gastric myoelectrical activity and its relation with vagal activity after exercise. METHODS: Nine subjects were studied in two sessions. In the control session, gastric myoelectrical activity was recorded using electrogastrography (EGG) for 30 min in the fasting state and 60 min after a test meal. In the exercise session, after the baseline recording of both the EGG and electrocardiogram (ECG), the subject was put on a cycle ergometer for exercise until reaching 50% of the maximum age-predicted heart rate for 10 min. The test meal was then given and the recording was resumed for 60 more minutes. Spectral analyses were performed on both the EGG and the heart rate variability derived from the ECG. RESULTS: The postprandial increment of the dominant power (p<0.05) and the percentage of the 2-4 cpm slow waves (p = 0.01) were significantly higher with exercise. The standard deviation of the postprandial dominant frequency was significantly decreased (more stable slow waves) with exercise (p<0.04). While cardiac vagal activity was significantly decreased after the meal, exercise did not significantly affect the postprandial change. CONCLUSIONS: Gastric slow waves become more regular, more stable, and of higher amplitude after exercise, and this enhancement is probably not mediated via the vagal pathway.     

Effects of acupressure on gastric myoelectrical activity in healthy humans

Objective. Acupressure at Neiguan point (P6) has been used as an antiemetic in Eastern countries and many studies have reported its effectiveness on gastrointestinal symptoms. The aim of the present study was to investigate the effects of acupressure on gastric myoelectrical activity in healthy humans. Material and methods. Fifteen healthy volunteers (9 M, 6 F) served as subjects. Acupressure at P6 was applied for 1 min followed by 1 min of rest, and this alternating sequence was continued for a total of 30 min. Electrogastrogram (EGG) was recorded for 30 min before (“baseline”), during (“acupressure”) and after (“recovery”) the application of acupressure. Heart rate variability (HRV) was also recorded to analyze autonomic nervous activities. Results. The percentage of normal 3 cycles per minute slow wave (%NSW) was changed significantly by the application of acupressure (86.5±2.4, 92.3±1.2, 92.8±1.9% in the baseline, acupressure and recovery periods, respectively, p=0.0424). The %NSW was significantly larger in the acupressure and the recovery periods than in the baseline period (p<0.03). The changes in %NSW from the baseline to the acupressure (r=?0.8598, p<0.001) and to the recovery (r=?0.6422, p<0.01) periods were negatively correlated with the baseline %NSW. There was no change in HRV. Conclusions. Acupressure at P6 increased %NSW of gastric myoelectrical activity. The negative correlation between the baseline value and the change in %NSW may extrapolate a possible normalizing effect of acupressure on impaired gastric myoelectrical activity in symptomatic patients.     

Gastric myoelectrical activity and gut hormone secretion in myotonic dystrophy

BACKGROUND: Myotonic dystrophy (MD) is a systemic disease affecting striated, cardiac and smooth muscles, as well as nerve structures and endocrine glands. Patients with MD may suffer from slow gastric emptying. OBJECTIVE: To study electrogastrograms (EGG) and postprandial gut hormone profiles in MD in order to evaluate whether disturbances in these regulatory mechanisms could explain, or contribute to, the delayed gastric emptying. SUBJECTS: Ten patients with MD complaining of symptoms consistent with slow gastric emptying, and ten healthy matched controls. METHODS: After an overnight fast, the patients and the control subjects were examined with standard EGG using surface electrodes before and during intake of a standard meal. Blood tests were drawn at regular time intervals for hormone analyses. RESULTS: The EGG in MD showed a reduced amount of normal three cycles per minute activity compared with controls (P < 0.04). The dominant frequency in MD was less stable than in controls (P < 0.03), and the power of the signal showed less increase after a meal. The postprandial increase in plasma motilin (P < 0.05) and glucagon-like peptide-1 (GLP-1) (P < 0.001) was significantly less pronounced in MD compared with controls, whereas the plasma concentrations of cholecystokinin (CCK), neurotensin (NT), peptide YY (PYY) and somatostatin (SOM) did not differ significantly. CONCLUSION: Disturbed electrophysiological control of the stomach and impaired secretion of gastrointestinal peptide hormones could contribute to slow gastric emptying in MD. Combined impairment of gastric pacing and gastrointestinal hormone responses was found in patients with the most prominent retardation of gastric emptying.     

Effect of acid suppression on gastric myoelectrical activity in GERD

BACKGROUND/AIMS: The study aimed to investigate whether acid suppression influences gastric myoelectrical activity in patients with reflux disease. METHODOLOGY: Twenty-eight patients with erosive esophagitis underwent electrogastrography. All patients were studied before and after esomeprazole. Subjects were divided into mild or moderate esophagitis in order to determine any variation in response related to esophagitis severity. RESULTS: The reflux symptom improved from 4.2 at baseline to 1.0 at week 8 (P < 0.001). A significant increase in postprandial gastric 3 cycle per minute (normal) activity was observed at week 8 (P < 0.05). There was also significantly increased postprandial gastric 3 cycle per minute (normal) activity in moderate esophagitis (P < 0.05). CONCLUSIONS: The effect of acid suppression on gastric myoelectrical activity is subtle with an enhancement in normal gastric myoelectrical activity. The myoelectrical response to acid suppression appears to be associated with esophagitis severity.     

Gastric emptying and myoelectrical activity in children with nonulcer dyspepsia

We examined the effect of oral cisapride on gastric emptying time and myoelectrical activity using real-time ultrasonography and cutaneous electrogastrography in 10 children with nonulcer dyspepsia. A clear dominant frequency close to 3 cpm was present both at baseline and after eight weeks of cisapride. After cisapride, nine children had an increase in the normal slow wave percentage and the mean percentage of normal slow wave was significantly different (71.90±5.19% vs 79.16±5.54%;P<0.01). Moreover, an increased stability of the dominant frequency, determined by computing the coefficient of variation before and after cisapride, was found (28.12±1.72% vs 23.61±3.47%;P<0.01). At baseline the gastric emptying time, expressed asT1/2, was 139.76±40.04 min and at eight weeks 119.76±30.04 min (P=0.06). As regards the relationship between EGG and gastric emptying, the proportion of children with improved normal slow wave percentage was similar to that with improvedT1/2 emptying (z=0.57,P=0.57). Thus, gastric electrical activity seems to be an important factor in the pathophysiology of nonulcer dyspepsia in children.     

Effects of acupressure on gastric myoelectrical activity in healthy humans

OBJECTIVE: Acupressure at Neiguan point (P6) has been used as an antiemetic in Eastern countries and many studies have reported its effectiveness on gastrointestinal symptoms. The aim of the present study was to investigate the effects of acupressure on gastric myoelectrical activity in healthy humans. MATERIAL AND METHODS: Fifteen healthy volunteers (9 M, 6 F) served as subjects. Acupressure at P6 was applied for 1 min followed by 1 min of rest, and this alternating sequence was continued for a total of 30 min. Electrogastrogram (EGG) was recorded for 30 min before ("baseline"), during ("acupressure") and after ("recovery") the application of acupressure. Heart rate variability (HRV) was also recorded to analyze autonomic nervous activities. RESULTS: The percentage of normal 3 cycles per minute slow wave (%NSW) was changed significantly by the application of acupressure (86.5+/-2.4, 92.3+/-1.2, 92.8+/-1.9% in the baseline, acupressure and recovery periods, respectively, p = 0.0424). The %NSW was significantly larger in the acupressure and the recovery periods than in the baseline period (p <0.03). The changes in %NSW from the baseline to the acupressure (r = -0.8598, p < 0.001) and to the recovery (r = -0.6422, p <0.01) periods were negatively correlated with the baseline %NSW. There was no change in HRV. CONCLUSIONS: Acupressure at P6 increased %NSW of gastric myoelectrical activity. The negative correlation between the baseline value and the change in %NSW may extrapolate a possible normalizing effect of acupressure on impaired gastric myoelectrical activity in symptomatic patients.     

Effect of hypo- and hyperthyroidism on gastric myoelectrical activity

Although hypo- and hyperthyroid patients have different symptoms in the gastrointestinal tract, the mechanism of thyroid action on the gut remains poorly understood. Thus the aim of this study was to investigate the effect of hypo- and hyperthyroidism on gastric myoelectrical activity, gastric emptying, dyspeptic symptoms. Twenty-two hyperthyroid (median age 45, 15 females) and 11 hypothyroid (median age 42, 10 females) patients were included into the study. Dyspepsia score, hypo- and hyperthyroid symptom scale, abdominal ultrasonography and upper gastrointestinal endoscopy were performed. Gastric myoelectrical activity was measured by electrogastrograpy (EGG) before and after therapy both preprandially and postprandially and compared with age, gender, and body-matched controls (12 for hypothyroid, 15 for hyperthyroid patients). Radionuclide gastric emptying studies were performed with a solid meal. Hypothyroid patients revealed a significant increase in preprandial tachygastria as compared with controls (12.3% vs 4.8%). The percentage of preprandial normal slow waves (2.4–3.7 cpm) was below 70% (dysmotility) in 7 of 11 hypothyroid patients versus 2 of 12 controls (P < 0.05). Hyperthyroid patients revealed a significantly higher preprandial (3.1 vs 2.8) and postprandial (3.4 vs 3) DF when compared with the controls (P < 0.05). A higher percentage of postprandial taschygastria (7.9 vs 0) was present in hyperthyroid patients than in the controls (P < 0.05). The decrease on postprandial EGG power (power ratio < 1) was observed in 7 patients the in hyperthyroid group and 1 in controls (P < 0.05). The percentage of postprandial normal slow waves was below 70% in 10 of 20 hyperthyroid patients vs 1 of 15 controls (P < 0.05). After therapy these differences disappeared in the euthyroid state. The hypo- and hyperthyroid symptom scale correlated to dyspepsia score. Dyspepsia score in hyperthyroidism correlated to power ratios in hyperthyroid patients. We detected some correlations between serum levels of fT3 or fT4 and some EGG parameters in hypo- and hyperthyroidism. Dyspepsia score and hypo- and hyperthyroid symptom scale were improved significantly after therapy in the euthyroid state. In conclusions, we showed gastric dysrhythmia by EGG in both hypo- and hyperthyroid patients. Dyspeptic symptoms correlated to the activity of thyroid disease. After therapy, these findings and dyspeptic symptoms improved in the euthyroid state. Abnormalities of power ratios may be responsible of dyspeptic symptoms in hyperthyroid patients. EGG may be a useful and noninvasive tool for detecting gastric disturbances during hypo- and hyperthyroidism.