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PubMed1996

Nicotine effects on prostaglandin-dependent gastric slow wave rhythmicity and antral motility in nonsmokers and smokers.

BACKGROUND & AIMS: Mechanisms of antral hypomotility with smoking are unknown. Slow wave disruption, which may be prostaglandin dependent, inhibits gastric motility. This study tested if nicotine reproduces motor effects of smoking and assessed the role of slow wave disruption in inducing hypomotility and the prostaglandin dependence of dysrhythmic responses. METHODS: Electrogastrography and antroduodenal manometry were performed in 9 nonsmokers and 9 smokers during transdermal nicotine treatment (14 mg). Studies were repeated after administration of 150 mg indomethacin daily for 3 days to test prostaglandin requirements of nicotine responses. RESULTS: Antral migrating motor complex periodicity and fasting and fed motility indices, not different in the groups under control conditions, decreased similarly in nonsmokers and smokers with nicotine. Tachygastria (> 4.5 cycle/min) increased from 2% +/- 2% to 16% +/- 3% of recording time, and arrhythmias (frequency instability index) increased from 0.5 +/- 0.1 to 1.1 +/- 0.2 cycle/min with nicotine in nonsmokers (P < 0.05), which normalized with indomethacin. Electrogastrography results were unchanged in smokers. CONCLUSIONS: Nicotine evokes antral hypomotility in nonsmokers and smokers but evokes prostaglandin-dependent gastric dysrhythmias only in nonsmokers. Smokes show desensitization to nicotine-stimulated dysrhythmias. Thus, slow wave disruption is not essential to inhibit motor activity. This provides a model for the motor and myoelectric effects of smoking.

Adolescent↗

PubMed1993

Colonic motor activity.

The colon exhibits three types of contractions: individual phasic (short and long duration), organized groups (MMCs and nonmigrating motor complexes), and ultrapropulsive (giant migrating contractions). The individual phasic contractions and the MMCs and nonmigrating motor complexes produce extensive mixing and kneading of fecal material and slow net distal propulsion. The GMCs produce mass movements and expel feces during defecation. All contractions are controlled by myogenic, neural, and chemical mechanisms. The myogenic mechanisms determine the timing and frequency of contractions and the duration and distance of propagation of contractions. The neurochemical mechanisms determine whether the contractions will occur at a given site.

Animals↗

PubMed1993

Gastrointestinal longitudinal muscle contractions.

The patterns of longitudinal muscle contractions of the stomach and the small intestine and their relationship with circular muscle contractions during the fasting and the fed state were investigated in conscious dogs. In the stomach, the longitudinal muscle contracted in a 1:1 relationship with the circular muscle contractions. There was no significant difference between the frequency, duration, and time of onset of gastric longitudinal and circular muscle contractions, and their amplitudes were significantly correlated with each other. In the small intestine when the circular muscle contracted, the longitudinal muscle exhibited passive elongation during the fasting and the fed state. There was no significant difference between the onset, duration, and frequency of small intestinal circular muscle contractions and the passive longitudinal muscle elongations; their amplitudes were strongly correlated with each other. During a circular muscle giant migrating contraction, the longitudinal muscle exhibited a monophasic contraction, initially a contraction followed by passive elongation or a pure passive elongation. During a retrograde giant contraction, the longitudinal muscle exhibited only a pure monophasic contraction or a contraction-elongation complex. These data suggest that the enteric nerves in the small intestine innervate the two muscle layers in a reciprocal fashion and those in the stomach in a complementary fashion.

Animals↗

PubMed1996

Ambulatory 24-hour jejunal motility in diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Whether small-bowel motility is abnormal in the irritable bowel syndrome (IBS) is a controversy at present. The aim of our study was to compare ambulatory long-term jejunal motility in 35 IBS patients with predominant diarrhea to normal values obtained in 50 healthy controls. METHODS: Twenty-four-hour motility was recorded in the proximal jejunum with a portable datalogger and tube-mounted miniature pressure sensors. Fasting motility in the waking (W) and sleeping (S) state and the motor response to a standardized evening meal of 600 kcal underwent visual and computer-aided analysis. RESULTS: Fasting motility in patients showed migrating motor complex (MMC) cycles of normal length and composition. Uninterrupted runs of discrete clustered contractions during phase II (W) occurred in 57% of patients and 52% of controls but had a significantly longer duration in patients (33 +/- 5 versus 19 +/- 7 min; p < 0.005). During phase II (W) IBS patients had an increase in aborally propagated contractions (41 +/- 2% versus 35 +/- 2%; p < 0.01) and higher contraction amplitudes (26.3 +/- 0.8 versus 23.0 +/- 0.5 mm Hg; p < 0.01). Similar differences were obtained during postprandial motility (47 +/- 3% versus 39 +/- 3%; p < 0.01, and 25.9 +/- 0.9 versus 23.8 +/- 0.05 mm Hg; p < 0.02). In three patients (8.6%) disturbed aboral migration of phase III and irregular burst activity, manometric features of chronic idiopathic intestinal pseudo-obstruction, were identified. Whereas 57% of patients had an entirely normal 24-h manometry, 43% had at least one finding not present in any healthy control. CONCLUSION: Small-intestinal motility is frequently but not universally abnormal in diarrhea-predominant IBS. The abnormal manometric findings are heterogeneous and range from subtle quantitative changes to severe qualitative abnormalities resembling chronic idiopathic intestinal pseudo-obstruction in a small subset of patients.

Adult↗

PubMed1991

Colonic motility in innervated and extrinsically denervated loops in dogs.

The control mechanism of canine colonic motor activity measured by means of chronically implanted force transducers was studied by comparing diurnal changes and migrating patterns in control dogs and dogs with innervated and extrinsically denervated colonic loops. Five force transducers (C1-C5) were placed on the colon, and the middle colon was transected to construct a loop including C2 and C3 transducers. Colonic continuity was established by an end-to-end anastomosis. In the fasted state, colonic motor complexes of 8-13 minutes' duration were observed to occur at intervals of 22-32 minutes in all three groups, but response to feeding was clearly different; significant enhancement of the colonic motor indexes lasting for 8-16 hours after feeding, which was observed at all recording sites in control dogs, was identified only in the proximal and distal colon in dogs with innervated and extrinsically denervated loops. In the innervated loop, significant enhancement of the motor indexes was observed only in the first 2 hours after feeding. In the extrinsically denervated loop, feeding did not induce any response. In both groups with loops, greater than 40% of the motor complexes that occurred in the proximal colon migrated to the distal colon directly across the anastomosis and less than 20% propagated to the loop. In addition, the migration time between the proximal and the distal colon was greatly reduced in both groups with loops compared with that in the control group. Another change observed within the loop was an increase in numbers of retrograde migrating colonic motor complexes. It is concluded that colonic motor activity is under the predominant control of intraluminal contents in the digestive state but that extrinsic nerves may play an important role in the response observed in the innervated loop in the first 2 hours after feeding, which should be defined as the gastrocolonic response in dogs. In the interdigestive state, the intrinsic nervous system and/or humoral factors may control the occurrence of colonic motor complexes.

Animals↗

PubMed1992

Enterohepatic circulation is essential for regular cycling of duodenal migrating motor complexes in dogs.

The role of enterohepatic circulation and specific bile acids in the initiation and caudad migration of duodenal migrating motor complexes (MMCs) was investigated in conscious dogs. All dogs had spontaneous duodenal MMCs that migrated to the terminal ileum when bile flow was intact. During the first 3 days after total external biliary diversion, no MMCs originated in the duodenum. Instead, all MMCs originated in the jejunum and migrated to the ileum. During the next 4 days of total external biliary diversion, 81% of the MMCs originated in the jejunum and 19% in the duodenum. When normal bile flow was restored after 9 days of total external biliary diversion, regular duodenal MMCs resumed after a delay of 126 +/- 27 minutes. Perfusion of individual bile acids or dogs' own bile, but not saline or alkaline solution, into the duodenum or perfusion of dogs' own bile directly into the ileum during total external biliary diversion restarted duodenal MMCs with a time lag of about 2 hours. The authors conclude that intact enterohepatic circulation is essential for the initiation of regular duodenal MMCs.

Animals↗

PubMed1998

Small bowel motility in primary biliary cirrhosis.

OBJECTIVE: Previous studies have shown small bowel motor activity abnormalities in patients with liver cirrhosis of different etiologies, but motility has not been studied in patients with primary biliary cirrhosis. Our aim was to investigate proximal small bowel motility in these patients. METHODS: Twenty-five female patients presenting clinical, biochemical, serological, and histological findings compatible with primary biliary cirrhosis, 10 female patients with nonalcoholic liver cirrhosis, and 10 normal female controls were studied. Motility of the upper small bowel was measured in the fasted state by means of perfused manometric catheters, connected to external transducers and positioned in the small bowel under fluoroscopy. RESULTS: The average amplitude of contractions was significantly decreased in patients with primary biliary cirrhosis compared with other liver cirrhosis (20.2+/-1.0 vs 32+/-2.9 mm Hg). Also, a significantly increased frequency of cluster of contractions and an increased duration of phase II of the migrating motor complex as seen in liver cirrhosis was observed when compared with normals. CONCLUSION: We conclude that primary biliary cirrhosis patients present motor abnormalities of the small intestine similar to those of patients with liver cirrhosis of other etiologies. In addition, a decrease in the amplitude of small bowel contractions was also found in these patients, suggesting a myogenic involvement.

Adult↗

PubMed2001

Pyloric relaxation regulated via intramural neural pathway of the antrum.

Current information about pyloric relaxation is not sufficient. For this reason, our study aimed at measuring pyloric relaxation correctly and determining the role of the intrinsic and extrinsic neural pathway in pyloric relaxation. Five groups of dogs were used: five dogs had an intact gastrointestinal tract (control group); five dogs had transection and reanastomosis of the antrum 3 cm proximal to the pylorus (antral transection group); five dogs had extrinsic pyloric denervation (denervation group); five dogs had transection and reanastomosis of the antrum with extrinsic pyloric ring denervation (transection with denervation group); and five dogs had truncal vagotomy (vagotomy group). Gastropyloroduodenal motility was recorded by a strain-gauge force transducer in conscious dogs. In the control and denervation groups, pyloric relaxation was observed only during phase III of the interdigestive migrating motor complex. In the antral transection, transection with denervation, and vagotomy groups, pyloric relaxation was not observed in either the interdigestive or the postprandial state. The frequency of pyloric contractions increased in these groups in comparison with the control group. In conclusion, the results suggest that pyloric relaxation occurred during phase III to expel undigested particles from the stomach and that descending antral intramural pathways play an important role in the control of pyloric relaxation.

Animals↗

PubMed1992

Vagus-dependent disruption of interdigestive canine motility by gastric distension.

The purpose of this study was to determine the effect of proximal gastric distension on interdigestive patterns of canine gastrointestinal motility and to examine the role of extrinsic nerves in regulating such an effect. Serosal electrodes were placed on the antrum, duodenum, and jejunum. Animals were studied before and after transthoracic vagotomy or after neural isolation of the entire jejunoileum (extrinsic denervation). Proximal gastric distension for 5 h was provided by inflating with air a thin complaint bag placed into the proximal stomach after the onset of phase III of the migrating motor complex (MMC). Four volumes (0, 1.5, 12.5, and 25 ml/kg) were each tested four times in each animal. In neurally intact animals, gastric distension with volumes of 12.5 and 25 ml/kg consistently abolished the MMC in the antrum (100%), duodenum (96%), and proximal jejunum (greater than or equal to 62%), but less often in distal jejunum (greater than or equal to 25%). After vagotomy, gastric distension did not inhibit cycling of the MMC in the antrum, duodenum, or proximal or distal jejunum. After extrinsic denervation of the jejunoileum, gastric distension inhibited the MMC in the antrum and the duodenum but had no effect in the proximal or distal jejunum. These findings suggest that nonnutrient proximal gastric distension may contribute to postprandial changes in patterns of myoelectric activity in the upper gastrointestinal tract and that this effect is mediated by the vagus nerves.

Animals↗

PubMedDate not supplied

Laparoscopic cholecystectomy: a minor abdominal trauma?

Clinical observations following laparoscopic surgery indicate a shorter period of postoperative ileus than after conventional surgery. The aim of our study was to verify disorders of postoperative motility of the small intestine by means of implanted electrodes after laparoscopic and conventional cholecystectomy (CHE) in an animal model. Four weeks after implantation of three electrodes on the jejunum, CHE was performed laparoscopically in 5 dogs and in an additional 5 dogs by laparotomy. Independent of the type of operation, normal motility (especially the migrating motility complex) was abolished during the early postoperative period. Electrical activity was characterized by the basic electrical rhythm. Time to the occurrence of the first postoperative activity front, indicating restoration of motility, varied significantly depending on the type of operation: It was 5.5 +/- 1.0 hours after laparoscopic CHE and 46 +/- 5 hours after conventional CHE. These results support the hypothesis that small peritoneal incisions and less manipulation of the intestine during laparoscopic surgery result in reduced abdominal trauma.

Animals↗

PubMed1992

Effects of fractionated doses of ionizing radiation on colonic motor activity.

The colonic motor effects of fractionated irradiation were studied in five conscious dogs. Seven colonic and two ileal strain gauge transducers were implanted. After control recordings, an abdominal dose of 250 cGy was administered three times a week on alternate days for three successive weeks (total dose 2,250 cGy). Recordings were then continued for 3 wk after the completion of radiation. Colonic giant migrating contractions (GMCs) occurred at a frequency of 0.15 +/- 0.05 contractions/h in the control state. Only one of these contractions (8.3%) originated in the small bowel and propagated into the colon. Abdominal field irradiation significantly increased the incidence of colonic GMCs to 0.51 +/- 0.11 contractions/h (P < 0.05). Fifty-four percent of GMCs originated in the small intestine. GMCs during the radiation schedule were associated with explosive diarrhea on seven occasions. Irradiation did not alter the frequency of colonic migrating motor complexes, but the mean duration of contractile states decreased in the middle and distal colon. Diarrhea occurred as early as the second dose of radiation. Pathological changes in the colon were correlated with motor activity. Both small intestinal and colonic GMCs reverted to control frequencies after cessation of radiation exposure. Abdominal irradiation significantly altered the contractile activity of the colon. These changes are associated with abdominal cramping and diarrhea.

Animals↗

PubMed1999

Cholecystectomy in patients with normal gallbladder function did not alter characteristics in duodenal motility which was not correlated to size of bile acid pool.

Nine gallstone patients with normal gallbladder function as assessed by hepatobiliary scintigraphy were included. Fasting and postprandial duodenal motility were studied before and one month after an uncomplicated laparoscopic cholecystectomy. An ambulatory continuous pressure recording was obtained from 5 PM to 8 AM with a sampling frequency of 4 Hz. At 6 PM, the patients received a 1400-kJ standard meal. The size of the bile acid pool after cholecystectomy was measured according to the dilution principle using [C14]cholic acid as the marker. Preoperatively the migrating motor complex (MMC) cycle was 0.48/hr (quartiles 0.42-0.68) compared to 0.68/hr (0.43-0.77) postoperatively. This difference was not significant. An increase in the MMC cycle frequency was observed postoperatively in three patients, and a decrease was seen in four patients. The migration velocity was 5.61 cm/min (4.26-8.01) preoperatively and 7.16 cm/min (4.79-9.71) postoperatively, a difference that was not significant. The time period from meal ingestion to appearance of phase III was 297 min (218-431) at the preoperative examination and 443 min (192-494) at the postoperative examination. This difference was not significant. The size of the bile acid pool after cholecystectomy was 3.68 mmol (2.69-8.47) and was not significantly correlated to the frequency of the MMC cycle or the time period from food ingestion to phase III activity. It is concluded that in gallstone patients with a normally functioning gallbladder, cholecystectomy does not alter duodenal motility, which was not correlated to the size of the bile acid pool.

Adult↗

PubMed1994

[Motility disorders in the blind loop after Roux-en-y reconstruction. Electromyography studies in the animal experiment].

Disturbances of intestinal motility, bacterial overgrowth and pancreocibal asynchrony are frequent findings in patients after Roux-en-y reconstruction (RYR). In dogs (n = 6) electromyographic recording of motility after partial gastrectomy with Roux-en-y reconstruction revealed no significant differences from controls in the Roux limb. However, changes in intestinal motility were extensively in the blind loop. The electromyographic pattern was characterized by an extreme loss of activity in the fasted and postprandial state. The activity front of the migrating motility complex occurred only in 25% of the fasting studies and was not correlated in time with motility patterns of connected small intestine. Food intake led to a significant increase in the motility index in the Roux limb (60.2 +/- 10.5), but not in the blind ending loop (27.8 +/- 4.1). Pharmacological stimulation of the hypomotile blind loop with cisapride is successful: increase of the motility index to 111.2 +/- 16.5. It might be useful in the treatment of symptomatic patients after RYR.

Anastomosis, Roux-en-Y↗

PubMed1999

Factors affecting outcome following proximal and distal intestinal resection in the dog: an examination of the relative roles of mucosal adaptation, motility, luminal factors, and enteric peptides.

In the clinical setting, resection of the ileum results in an inferior functional outcome compared to jejunal resection. This may be related to a greater adaptive capacity of the ileum, intrinsic structural and functional differences, or regional differences in motor and hormonal function. Our aim was to evaluate the relative contributions of these factors to functional outcome after resection of the proximal or distal intestine. Twenty-four dogs underwent either intestinal transection or 50% resection of the proximal or distal intestine. Studies (nutritional status, absorption, adaptation, motility, peptide levels) were performed every four weeks until the animals were killed at 12 weeks. Caloric intake was similar in all four groups. Weight loss was greater and more sustained after distal resection (DR). Serum cholesterol levels decreased significantly only in the DR group. While stool weight and moisture were similar, the DR animals had persistent, significant steatorrhea. Intraluminal anaerobic bacteria and SCFA concentrations were significantly greater in the ileum but were not influenced by resection. Intestinal remnant length increased to a greater extent after proximal resection (PR), but circumference increased to a similar extent after both resections. Villus height and crypt depth increased significantly only after PR. MMC frequency was similar in all four groups. In the DR animals 26% of migrating motor complexes (MMCs) originated within the remnant. The jejunal remnant of these animals had a dominance of cluster activity similar to the intact distal ileum. Following PR, the postprandial motilin response was decreased. After DR, there were transient increases in neurotensin and PYY. Of the various factors evaluated, mucosal adaptation and the intestinal motor response appear most likely to explain the inferior nutritional and absorptive outcome associated with resection of the distal small intestine.

Adaptation, Physiological↗

PubMed2002

Effect of truncal vagotomy on sphincter of oddi cyclic motility in conscious dogs.

OBJECTIVE: To evaluate the effects of truncal vagotomy at the diaphragmatic level on the sphincter of Oddi (SO) motility. SUMMARY BACKGROUND DATA: Cholelithiasis is a well-known late complication after gastrectomy and/or vagotomy. The mechanism of gallstone formation is only partly understood, and few studies address the effects of vagotomy on SO cyclic motility in conscious subjects. METHODS: In conscious dogs, SO motility was recorded by retrograde infusion manometry through a duodenal cannula before and after bilateral truncal vagotomy at the diaphragmatic level. Effects of cholecystokinin-octapeptide and feeding were also evaluated before and after vagotomy. RESULTS: SO cyclic motility and the gastroduodenal migrating motor complex continued to occur during postvagotomy fasting. Intermittent inhibitions of the SO and duodenal contractions disappeared during phase 3 of the migrating motor complex. SO basal pressure significantly decreased, whereas the amplitude significantly increased. Cholecystokinin-octapeptide inhibited SO contractions before and after vagotomy. The amplitude of SO contractions increased and their frequency decreased after feeding; however, these effects disappeared after vagotomy. CONCLUSIONS: SO cyclic motility and the effects of feeding change after truncal vagotomy at the diaphragmatic level. These facts may at least partly explain gallstone formation after gastric surgery and/or vagotomy.

Animals↗

PubMed2005

Comparison between partial agonist (ME3412) and antagonist (alosetron) of 5-hydroxytryptamine 3 receptor on gastrointestinal function.

Therapeutic use of 5-hydroxytryptamine 3 (5-HT(3)) receptor antagonists for diarrhoea-predominant irritable bowel syndrome may be accompanied by constipation. We hypothesized that ME3412, 5-chloro-2-(1,4-diazacycloheptan-1-yl)-7-methylbenzoxazole, a novel partial agonist of the 5-HT(3) receptor, would minimize constipation without reducing antidiarrhoeal activity. Receptor binding studies showed that ME3412 is highly selective for the human 5-HT(3) receptor (K(i) = 1.51 nmol L(-1)). A 5-HT(3) receptor agonist, 2-methyl-5-HT, caused contractile response in the isolated guinea-pig ileum and accelerated secretion in the guinea-pig colonic mucosal preparation. ME3412 and 5-HT(3) receptor antagonist, alosetron, antagonized the 2-methyl-5-HT-induced responses with similar potency in insurmountable and surmountable manner, respectively. ME3412 caused weak agonism in isolated ileum strips and also in the colonic mucosa with intrinsic activity of 0.09 and 0.59, respectively. In conscious dogs, alosetron (3 microg kg(-1) i.v.) suppressed the migrating motor complex (MMC), whereas a relatively high dose (300 microg kg(-1)) of ME3412 was required for inhibition of MMC. ME3412 and alosetron suppressed 5-HT induced-diarrhoea in mice. In contrast, ME3412 did not significantly affect colonic propulsion compared with alosetron. These results imply that the partial agonist may relieve diarrhoea with low risk of inducing constipation.

Animals↗

PubMed1997

Antroduodenal manometry in children with no upper gastrointestinal symptoms.

BACKGROUND: The interpretation of antroduodenal manometry in children with gastrointestinal motility disorder has been limited by a paucity of data from normal children. The purpose of this study was to define antroduodenal manometry findings in children with no upper gastrointestinal symptoms. METHODS: We reviewed 260 consecutive antroduodenal manometries and selected 18 studies from subjects aged 2-12 years with no symptoms referable to a gastrointestinal motility disorder involving the stomach and/or the small bowel. RESULTS: During fasting, phase 3 of the migrating motor complex (MMC) was present in 14 of 18 children, and it was induced by erythromycin in 4 who failed to have a spontaneous phase 3. Phase 3 propagation velocity increased significantly with age. The cycle length between MMCs showed no age-dependent variation. Phase 3 occupied 3%; phase 1, 10%; and phase 2, 87% of the fasting recording time. CONCLUSIONS: Antroduodenal manometry findings in children with no upper gastrointestinal symptoms are similar to those in adults.

Adult↗

PubMed1996

The correlation in dyspeptic patients of Helicobacter pylori infection with changes in interdigestive gastroduodenal motility patterns but not in gastric emptying.

BACKGROUND: Available data conflict regarding the possible relation between chronic gastritis, Helicobacter pylori (Hp), and gastric motor disorders in nonulcer dyspepsia. The aim of this study, therefore, was (1) to evaluate both gastroduodenal fasting motility and gastric emptying in subjects with functional dyspepsia, with and without gastritis, and (2) to correlate the motility pattern to Hp infection. MATERIALS AND METHODS: Thirty-eight patients were studied, 20 positive for Hp infection (15 with gastritis) and 18 Hp-negative (8 with gastritis). All the subjects underwent 240-minute manometric recording of the interdigestive migrating motor complex, with evaluation of gastric and duodenal motility pattern and scintigraphic study of gastric emptying. RESULTS: Whereas gastric emptying half-time did not differ in the subgroups of dyspeptic patients, a significant reduction of gastric phase IIIs of the migrating motor complex was detected between Hp-positive and Hp-negative subjects, both in overall patients (p < .01) and in patients with gastritis (p < .05). CONCLUSION: Hp infection seems to be related to a reduction of interdigestive gastric activity fronts, though it does not affect gastric emptying. The conflicting data regarding gastric emptying and interdigestive motility in Hp infection could be explained as probably investigating two different functional aspects.

Adult↗