Interdigestive Motor Complex Research Articles

Does motilin peptide regulate gastrointestinal motility of zebrafish? An in vitro study using isolated intestinal strips

Motilin (MOT), a 22-amino-acid peptide hormone produced in the duodenal mucosa, stimulates gastrointestinal motility in mammals and birds, and it is a mediator of interdigestive motor complexes. Recently, expression of MOT-like peptide (MOTLP) and its receptor mRNAs was identified in zebrafish. The aim of the present study was to determine whether the zebrafish MOTLP (zfMOTLP, HIAFFSPKEMRELREKE) affects zebrafish gastrointestinal motility, with comparison to the effect of human MOT, in which five amino acids are identical to zfMOTLP at positions 5, 9, 15, 16, and 17. zfMOTLP caused small contractions of the rabbit duodenum and chicken ileum but, the sensitivity was about 3000-times lower than that of human MOT. zfMOTLP-induced contraction in the rabbit duodenum was decreased by pretreatment of the MOT receptor antagonist GM109, indicating that zfMOTLP could bind to the MOT receptor. zfMOTLP (3–100nM) increased the intracellular Ca2+ concentration in zfMOT receptor-expressing HEK293 cells, but human MOT did not cause responses even at 100nM. In in vitro study using isolated zebrafish gastrointestinal strips, zfMOTLP caused only small contractions even at high doses (1–10μM). zfMOT receptor mRNA is detected in the gastrointestinal tract and brain to almost the same extent, and the expression level (40–70 copies/100ng total RNA) is much lower than that in the chicken gastrointestinal tract. These results suggest that the MOTLP/MOT receptor system is present in zebrafish, but its physiological role for regulation of gastrointestinal motility might be not significant due to the weak contractile activity and low expression level of the receptor.

Erythromycin Use Before Induction of General Endotracheal Anesthesia.

Czarnetzkiandcolleagues1conductedasingle-center,doubleblind, placebo-controlled clinical trial in 132 patientswhounderwentemergent surgery for traumaorconditions suchasappendicitis and cholecystitis. The authors hypothesized that erythromycin given intravenously 15 minutes before intubation decreases the volume of gastric contents, potentially decreasing the risk for aspiration, by creating a clear stomach (<40 mL of liquids and no solid food as determined by endoscopy). Their hypothesis proved true for patients undergoing emergent surgery but not in the trauma population. The findings of this study are similar to those of Asai and colleagues2 who showed that preoperative erythromycin administrationreduces residualgastricvolumeandacidity.Erythromycin has also been used before endoscopy for acute upper gastrointestinal tract bleeding because it reduces the amount of blood present in the stomach.3 However, the conclusions of this study byCzarnetzki and colleagues1 must be interpreted with caution. First, the hypothesis was true only in the nontrauma patient population. Patients who underwent appendectomy or cholecystectomy had been fasting for 15 to 20 hours. Because these conditions rarely causediffuseperitonitiswith aparalytic ileus, thesepatients probably had a normal interdigestive motor complex, and a clear stomach might have been present independently from erythromycin administration. In contrast, trauma patients had been fasting for only 6 hours.We have no information about the type of trauma (extremity vs blunt or penetrating abdominal). Second, to say that themedicationdecreased gastric volume,we should know the volumebefore themedicationwasadministered.Third, the real endpoint shouldhave been the incidenceofaspiration,which thestudywasnotpowered todetect. Finally, erythromycin shouldbeusedwith cautionbecauseofan increasedrisk forcardiacarrhythmias,which predisposepatients to torsadesdepointes and cardiac arrest.4

Toward a Wireless Electronic Capsule With Microsensors for Detecting Dysfunction of Human Gastric Motility

This paper presents a method for detecting human gastric-motility dysfunction using a wireless electronic capsule. The capsule's main components include an application-specific integrated circuit, three sensors (temperature, pH, and pressure), an RF transceiver, and batteries. In addition, a portable data recorder was developed to receive and store the data transmitted by the wireless capsule. In particular, experimental results indicated that the maximum error and measuring range of the pressure sensor were 0.15 and 90-120 kPa, respectively. Using pressure data from the human stomach, a joint algorithm based on phase space reconstruction and independent component analysis was applied in the analysis of gastric motility. Implementation results showed that this joint algorithm could effectively obtain the components of pressure data for the human stomach that were caused by breathing, movement, contractions of abdominal muscles, and electrogastrogram. In 24 human experiments, poor gastric motility (functional dyspepsia and delayed gastric emptying) was identified with a recognition rate of nearly 80%. In particular, interdigestive motor complex and digestive motor complex related to human gastric motility were also identified.

Effects of 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists on gastrointestinal motor activity in dogs

To study the effects of 5-hydroxytryptamine (5-HT) receptor antagonists on normal colonic motor activity in conscious dogs. Colonic motor activity was recorded using a strain gauge force transducer in 5 dogs before and after 5-HT2B, 5-HT3 and 5-HT4 receptor antagonist administration. The force transducers were implanted on the serosal surfaces of the gastric antrum, terminal ileum, ileocecal sphincter and colon. Test materials or vehicle alone was administered as an intravenous bolus injection during a quiescent period of the whole colon in the interdigestive state. The effects of these receptor antagonists on normal gastrointestinal motor activity were analyzed. 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists had no contractile effect on the fasting canine terminal ileum. The 5-HT3 and 5-HT4 receptor antagonists inhibited phase III of the interdigestive motor complex of the antrum and significantly inhibited colonic motor activity. In the proximal colon, the inhibitory effect was dose dependent. Dose dependency, however, was not observed in the distal colon. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity. The 5-HT3 and 5-HT4 receptor antagonists inhibited normal colonic motor activity. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity.

Intestinal chronic obstruction affects motor responsiveness of rat hypertrophic longitudinal and circular muscles

Extensive morphological and neurochemical changes have been experimentally and clinically documented in the hypertrophied intestine located orally to a chronic partial stenosis of the lumen. Functional studies revealed not only disruption of the interdigestive motor complex in vivo and decreased efficiency of contraction but also preservation of the peristaltic reflex in vitro. Given the critical role played in intestinal peristalsis by the coordinated activity of the longitudinal (LM) and circular muscle (CM), this work focuses on the motor responses of LM and CM isolated from rat hypertrophied ileum following mechanical obstruction. Maximal contractions to both receptor (acetylcholine and substance P) and non-receptor (K+) mediated stimuli were up to 10-fold increased in hypertrophic CM rings compared with control tissues, while a higher potency of substance P was revealed in both hypertrophied muscle layers. Relaxations to vasoactive intestinal polypeptide and 8-Br-cGMP were more intense on prostaglandin F(2alpha)-contracted hypertrophic LM strips compared with control tissues and a general tendency towards increased relaxation was shared also by hypertrophic CM basal tone. The present results collectively suggest that hypertrophic growth leads to hyperresponsiveness to contractile agents, particularly evident in the CM, and to increased sensitivity to relaxing mediators, especially exhibited by the LM. In this regard, the complementary role exerted by each muscle layer and the plasticity of the intestinal tissue could both come into play to preserve the intestinal functions in a changing environment.

Effect of vagal denervation on canine gallbladder motility.

There is an increased incidence of gallstones after truncal vagotomy but the mechanism is unknown. Our aim was to study the early effects of vagotomy on fasting and postprandial gallbladder motility. A chronic model was constructed in 10 dogs to correlate gallbladder motility and emptying with interdigestive and postprandial duodenal motility both before and after selective hepatobiliary vagotomy (five dogs) and truncal vagotomy (5 dogs). During each study recordings were made for one complete interdigestive motor complex (IDMC) and for 90 min after a standard meal of (a) gallbladder and duodenal motility, (b) gallbladder emptying (by a dual radioisotope marker technique) and (c) duodenal output of bilirubin. In control studies the gallbladder contracted at the start of phase II of the interdigestive motor complex and ejected 20-25 per cent of its contents into the duodenum; after meals the gallbladder contracted within 5 min and emptied almost 80 per cent of its contents within 90 min. After both selective hepatobiliary vagotomy and also truncal vagotomy there was no significant difference in the pattern of contraction or emptying of the gallbladder either during fasting or postprandially. We conclude that gallbladder motility and emptying are entirely normal in the early period after vagal denervation.

Human stomach has a recordable mechanical activity at a rate of about three cycles/minute.

To discover whether the human stomach contracts every 20 seconds or not. Manometric study. Teaching hospital, Belgium. 10 healthy volunteers, and 31 patients who had had the whole stomach denervated and pulled up to the neck for oesophageal replacement. Analysis of selected strips of manometric tracings obtained with intraluminal perfused catheters. 13 patients were given erythromycin (1 g/day) by mouth. Estimation of the rate and frequency distribution according to amplitude of intraluminal pressure waves with the vertical axis of the tracings scaled up to reflect contractions within the gastric wall. Microwaves (<9 mmHg) that came in between conventional macrowaves (>9 mmHg) were found, showing that the human stomach undergoes mechanical activity (amplitude ranging from 0.2-310 mmHg) at the pacemaker's rate which varied from 2.43 to 3.60 cycles/minute from one subject to another. Phase I of the interdigestive motor complex contained microwaves only, phase II and the fed pattern consisted of a mixture of microwaves and macrowaves, and phase III contained macrowaves only. The fasting rate of mechanical activity was lower in patients who were given erythromycin than in those not given erythromycin (p = 0.003) and in healthy volunteers (p=0.002), and it increased significantly after a meal (p < 0.0001). Microwaves in strips in which they were the most prominent were of higher amplitude in patients than in healthy volunteers (median: 3.5 compared with 2.5 mmHg; p < 0.0001). The human stomach has mechanical activity at the rate at which the pacemaker generates electrical slow waves. The classic phases of the gastric motor activity seem to differ from each other by the frequency distribution of pressure waves according to amplitude rather than by the contraction rate. Weak mechanical activity is much more readily detectable after the stomach has been denervated and tailored for oesophageal substitution.

Effect of a Lacto-ovo Vegetarian Diet on Fasting Small Intestinal Motility

Background: Changes in diet can alter gastric and small intestinal (SI) motility. The effects of a vegetarian diet on fasting SI motility are unknown. Methods: Manometric studies were performed in 9 lacto-ovo vegetarians (7 women) and 9 omnivores (7 women) of similar age and body mass index. On each study day, manometry was used to assess SI motility for 5 h, or 3 complete cycles of the interdigestive motor complex (IDMC). Lacto-ovo vegetarians were studied once; omnivores were studied twice, on their usual diet, and after consuming a 14-day lacto-ovo vegetarian diet. Diet diaries were kept for 5 days prior to each manometric study. Data were analysed for dietary composition and for cycle length and duration of each phase (I, II and III) of the IDMC. Results:

Human stomach has a recordable mechanical activity at a rate of about three cycles/minute.

To discover whether the human stomach contracts every 20 seconds or not. Manometric study. Teaching hospital, Belgium. 10 healthy volunteers, and 31 patients who had had the whole stomach denervated and pulled up to the neck for oesophageal replacement. Analysis of selected strips of manometric tracings obtained with intraluminal perfused catheters. 13 patients were given erythromycin (1g/day) by mouth. Estimation of the rate and frequency distribution according to amplitude of intraluminal pressure waves with the vertical axis of the tracings scaled up to reflect contractions within the gastric wall. Microwaves (<9 mmHg) that came in between conventional macrowaves (>9 mmHg) were found, showing that the human stomach undergoes mechanical activity (amplitude ranging from 0.2-310 mmHg) at the pacemaker's rate which varied from 2.43 to 3.60 cycles/minute from one subject to another. Phase I of the interdigestive motor complex contained microwaves only, phase II and the fed pattern consisted of a mixture of microwaves and macrowaves, and phase III contained macrowaves only. The fasting rate of mechanical activity was lower in patients who were given erythromycin than in those not given erythromycin (p = 0.003) and in healthy volunteers (p = 0.002), and it increased significantly after a meal (p < 0.0001). Microwaves in strips in which they were the most prominent were of higher amplitude in patients than in healthy volunteers (median: 3.5 compared with 2.5 mmHg; p < 0.0001). The human stomach has mechanical activity at the rate at which the pacemaker generates electrical slow waves. The classic phases of the gastric motor activity seem to differ from each other by the frequency distribution of pressure waves according to amplitude rather than by the contraction rate. Weak mechanical activity is much more readily detectable after the stomach has been denervated and tailored for oesophageal substitution.

A normal gastrointestinal motility excludes chronic intestinal pseudoobstruction in children.

Gastrointestinal manometry has gained wide acceptance in the approach to patients with suspected enteric neuromuscular disorders. However, performing gastrointestinal manometry in these subjects without a previous exhaustive diagnostic evaluation is unjustified. Twelve children (median age: 7.0 years; range: 8 months-13 years), with clinical and x-ray features suggesting chronic intestinal pseudoobstruction, were referred to our unit for gastrointestinal manometry. The latter was performed with a perfused catheter for 5 hr in the fasting state and for 90 min after feeding. Data were compared with those recorded in eight age-matched controls. In all patients and controls, interdigestive motor complexes with propagated phases III were detected; a regular postprandial antroduodenal motor activity was also recorded. Patients and controls did not differ for fed antral and duodenal motility indexes, fed antroduodenal coordination, and length of duodenal phase III. Most of the patients showed short or prolonged bursts of nonpropagated activity in the fasting and/or fed states; in four cases fasting and/or fed sustained phasic activity was recorded. Manometric evidence of migrating motor complexes and postfeeding activity did not support the diagnosis of intestinal pseudoobstruction and suggested redirecting the diagnostic evaluation. Final diagnoses were: Munchausen syndrome-by-proxy (four cases), celiac disease (two cases), intestinal malrotation (two cases), Crohn's disease (two cases), multiple food intolerance (one case), and congenital chloride-losing diarrhea (one case). It is concluded that in children with suspected chronic intestinal pseudoobstruction manometric evidence of migrating motor complexes and fed motor activity excludes an enteric neuromuscular disorder and suggests a reassessment of the diagnostic work-up. Furthermore, if gastrointestinal manometry shows migrating motor complexes and postfeeding motor activity, qualitative abnormalities of the manometric tracings do not indicate an underlying enteric neuromuscular disorder and must not be overemphasized. Patients referred for gastrointestinal manometry should previously undergo an extensive diagnostic investigation to exclude disorders mimicking chronic intestinal pseudoobstruction.

Distal small bowel hormones: correlation with fasting antroduodenal motility and gastric emptying.

The aim of the present study was to study the interdigestive motor complex (MMC), distal small intestinal hormones, and gastric emptying in normal-weight and obese subjects before and after jejunoileal bypass (JIB). Therefore, fasting antroduodenal motility, gastric emptying, and RIA for motilin (MOT), neurotensin (NT), peptide YY (PYY), and glucagon-like peptide-1 (GLP-1) was performed in nine obese subjects before (BMI 42 +/- 4 kg/m2) and nine months after (BMI 31 +/- 4) JIB, and in two groups of nine age- and sex-matched controls (BMI 23 +/- 1 and 21 +/- 1). The rate of gastric emptying was faster in obese subjects and GLP-1 lower compared to normal-weight controls. After JIB, fewer phase III of the MMC were observed; fasting levels of PYY were elevated during the MMC; postprandial levels of NT, PYY, and GLP-1 were elevated; and gastric emptying was delayed. Our results suggest that there may be an association between an impaired GLP-1 response after food intake and obesity, and after JIB, PYY seems to regulate interdigestive motility while GLP-1 may regulate early gastric emptying.

Interrelation between cutaneous electrogastrogram and interdigestive motor complex

Interrelation between cutaneous electrogastrogram and interdigestive motor complex

Nonulcer Dyspepsia: A Look Into the Future

Nonulcer Dyspepsia: A Look Into the Future

The Mode of Roux-en-Y Reconstruction Affects Motility in the Efferent Limb

To compare motility of a Roux-en-Y esophagojejunostomy after total gastrectomy with normal jejunal motility and to determine the effect on motility of the incorporation of a pouch in the reconstruction. Jejunal motility in normal subjects was compared with jejunal motility in the Roux-en-Y reconstruction with and without a Hunt-Lawrence pouch. The case were collected during a 4-year period at a university hospital. The mean time from resection to study was 14 months (range, 4 to 49 months). Seven control patients were compared with 10 patients with a Roux-en-Y reconstruction and 17 with a Roux-en-Y and Hunt-Lawrence pouch. The fasting-state motility of the jejunum used for reconstruction was measured by a water-perfused manometric system for 2 to 4 hours with the subject in the supine position. Compared with normal subjects, patients with a Roux-en-Y esophagojejunostomy without a pouch had an increased number of phases of the interdigestive motor complex per hour (P < .05). The phases were of shorter duration with a random sequence and increased total time spent in the quiescent phase 1 (P < .05). In patients with a pouch, no differences were detected between the motility in the pouch and the efferent limb. Compared with those without a pouch, there were significantly fewer orthograde interdigestive motor complex phase 3 fronts and more total time spent in phase 1 (P < .05). Construction of a gastric substitute from jejunum leads to substantial motility changes. The addition of a pouch decreases the overall activity, which may contribute to the storage function of the pouch.

Relationship between surface electrogastrography and antropyloric pressures

The cutaneous electrogastrogram (EGG) and intraluminal antropyloroduodenal pressures were recorded in 12 healthy volunteers for 30-min periods during phase II of the interdigestive motor complex, during intraduodenal infusion of 10% triglyceride, and after intravenous erythromycin (3 mg/kg). During phase II, the frequency of the EGG was relatively constant in each individual, with a median frequency of 0.046 Hz [2.8 counts per minute (cpm)]. EGG frequency was greater (P < 0.05) than the median rate of antral pressure waves (1.8 cpm). The suppression of antral pressure waves (P < 0.05) and stimulation of isolated pyloric pressure waves (IPPWs) (P < 0.05) produced by triglyceride infusion were not associated with changes in EGG frequency compared with phase II. The frequency of the EGG and the rate of IPPWs were comparable. After erythromycin, EGG frequency was 0.03 Hz (1.8 cpm), less than during both phase II and triglyceride infusion (P < 0.05) and almost identical to the rate of antral pressure waves. Pressure waves were nearly always associated with an EGG signal. In contrast, the temporal relationship between the EGG signal and pressure waves was variable. During triglyceride infusion (r = 0.83, P < 0.001) and after erythromycin (r = 0.83, P < 0.001) there was a close (approximately 1:1) relationship between the rate of pressure waves and EGG frequency. However, there was no significant relationship (r = 0.32, not significant) between the number of pressure waves and EGG frequency frequency during pase II.(ABSTRACT TRUNCATED AT 250 WORDS)

A selective NK‐2 antagonist blocks the increase of canine colonic tone and ileal contractions induced by the NK‐2 selective receptor agonist, [βAla8] neurokinin A‐(4–10)

The regulatory roles of tachykinins in intestinal motor function may be clarified by use of novel, stable and selective antagonists of neurokinin receptors. We studied the effects of the non-peptide NK-2 receptor antagonist SR48968 on canine colonic tone under resting conditions and after stimulation by the selective NK-2 receptor agonist [beta Ala8] neurokinin A-(4-10). Experiments were performed in three conscious female dogs. Proximal colonic tone was recorded by a barostat and intraluminal pressures were recorded in the terminal ileum. 10, 15 and 20 cm orad to the ileocaecal junction. In separate experiments, and in a random sequence, dogs received an i.v. injection of the NK-2 antagonist SR48968, 10, 100, 1000 micrograms/kg, followed after 30 min by 2 micrograms/kg of the agonist [beta Ala8] neurokinin A-(4-10). Experiments were replicated twice in each dog. The NK-2 agonist increased colonic tone, and SR48968 antagonized these effects in a dose-dependent fashion (Spearman's rank, r = 0.86; P < 0.01); antagonism was complete at the highest dose. SR48968 alone had no effect on colonic tone and ileal motility. When given during phase I or II of the interdigestive motor complex, [beta Ala8] neurokinin A-(4-10) increased ileal contractions: pre-treatment with SR48968 blocked this increase in ileal motility. When given during phase III, [beta Ala8] neurokinin A-(4-10) interrupted the motility front; this effect was not antagonized by SR48968. SR48968 antagonizes the increase in canine colonic tone and ileal motility induced by activation of NK-2 receptors. However, SR48968 by itself had no effect on the control of colonic tone and ileal motility under unstimulated conditions. SR48968 may be useful for investigating the physiological role of tachykinins on the gastrointestinal tract.

Return of interdigestive motor complex after abdominal surgery

Gastrointestinal mechanical activity was studied in 13 patients after different surgical procedures in a fasted and fed state and after pharmacological stimulation. Mechanical activity was recorded by means of a multi-pressure sensor probe placed intraoperatively into the jejunum. Abdominal surgery abolished normal motility only for a short period of time. The time for the reappearance of regular recurring activity fronts varied with the type of the surgical procedure from 3 hr after cholecystectomy to the sixth postoperative day after colon resection. The fed pattern occurred after the first postoperative interdigestive motor complex in all experiments. Stimulation was observed with ceruletide, which induced contractile activity in the small intestine during postoperative ileus. No coordinated caudad propagating activity was observed. The postoperative interdigestive motor complex did not correlate in time with the first passage of flatus and stool in our patients. Thus, the restoration of motility in the small intestine did not coincide with the clinical relief from the so-called "physiological" postoperative ileus.

The effect of a new synthetic cholinergic compound (Aclatonium Napadisilate) on interdigestive motility and pancreatic function in humans

To investigate the effect of aclatonium napadisilate (Ac), a synthetic cholinergic compound, on human interdigestive gastrointestinal function, six healthy volunteers underwent gastrointestinal intubation for measurement of duodeno-jejunal motor activity and pancreatic enzyme secretion. Each subject was studied twice on two separate days and received either aclatonium (300 mg) or placebo intraduodenally in randomized order. Aclatonium significantly increased the overall length of the cycle of interdigestive motor complex (IMC) by a mean of 34% (p less than 0.05) without stimulating the phases of increased motor activity. Aclatonium slightly, but significantly increased output of lipase during phase II of the IMC (p less than 0.05), whereas outputs during phase I and III were not significantly changed. We conclude that aclatonium in a dose of 300 mg has only weak cholinergic effects on motility and exocrine pancreatic secretion in healthy humans during the interdigestive state.

The Rectal Motor Complex

To identify patterns of motility in the rectum of humans during the day while awake and at night during sleep, and to correlate the patterns with interdigestive duodenal motor complexes and sleep cycles, intraluminal rectal pressure was recorded in 12 healthy subjects (five female, seven male; mean age, 28 years) using a flexible, noncompliant, silastic catheter and an Arndorfer system with a single perfused rectal port 6 cm above the anorectal junction, duodenal motility was recorded via a perfused oroduodenal tube, and sleep stages were determined electroencephalographically. Discrete bursts of rectal motor waves, called rectal motor complexes (RMCs), were identified on 72 occasions in 11 of the 12 subjects during 157 hours of recording. The RMCs were found in daytime during fasting or after feeding (0.2 ± 0.1 RMCs/hour), but were more easily and frequently identified at night during sleep (0.8 RMCs/hour, p &lt; .01). The complexes had a distinct onset, a mean duration ± SEM of 9.5 ± 1.0 minutes, and a distinct decline. Within each complex, the waves had a mean frequency of 3.8 ± 0.3 per minute and a mean amplitude of 19 ± 2.7 mm Hg. Complex‐to‐complex intervals at night averaged 74 ± 15 minutes. No clear‐cut temporal association was present between the complexes and phase III of interdigestive duodenal motor complex or the REM stage of sleep.

Interdigestive myoelectric complex in germ-free rats.

The effect of intestinal bacteria on the interdigestive myoelectric complex (IDMEC) was studied by recordings of the electrical activity of the proximal and distal small bowel in fasting germ-free (n = 6), gnotobiotic (n = 7), and conventional (n = 6) rats in vivo. Germ-free and gnotobiotic rats were operated and studied in germ-free or gnotobiotic conditions. The IDMEC period (mean +/- SD) in the proximal and distal small bowel was significantly longer in germ-free rats (20 +/- 2 min and 102 +/- 14 min) as compared to conventional rats (13 +/- 1 min and 58 +/- 5 min). Association of germ-free rats with a limited flora (gnotobiotic rats) decreased the IDMEC period significantly (15 +/- 1.5 min and 75 +/- 14 min). The migration velocity of the IDMEC was inversely related to the IDMEC period. These observations confirm previous data suggesting that the interdigestive motor complex has a role in the homeostasis of the bacterial content of the small bowel.