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PubMed1992

Differences between jejunal myoelectric activity after a meal and during phase 2 of migrating motor complexes in healthy humans.

Using an intraluminal probe with six pairs of annular electrodes, the myoelectric activity of the proximal jejunum was recorded during 48-hr sessions in 16 healthy volunteers receiving evening and noon meals (1000 kcal) and breakfast (400 kcal). In 10 subjects receiving no drug, the characteristics of the migrating motor complexes (period, duration of each phase, velocity of propagation of phase 3, duration of the postprandial disruption) varied markedly between subjects but were relatively constant from the first to the second day of recording. Single spike bursts propagated at a rate of 2-5 cm/sec, clusters of 3-10 spike bursts propagated at a rate of 0.5-1 cm/sec, and similar clusters recurring repetitively each 1.5-2 min were observed after the meals and very rarely in the fasted state during phase 2 of nocturnal migrating motor complexes. In six subjects, oral administration of codeine (50 mg) 1 hr before a meal induced migrating motor complexes in the postprandial state, with characteristics similar to that observed in the fasted state except a longer duration of phase 2. Single spike bursts and isolated and repetitive clusters of spike bursts were observed during phase 2 of the codeine-induced migrating motor complexes and after meals preceded by placebo, but very rarely during the phase 2 of nocturnal (fasted state) migrating motor complexes. It is concluded that the patterns of jejunal contractions consisting of propagated single spike bursts and isolated or repetitive spike bursts characterize the postprandial state in healthy humans and are dependent upon digesta flow.

Adult↗
PubMed2000

Effects of trimebutine on intestinal motility after massive small bowel resection.

Effects of trimebutine maleate (TM) on intestinal motility in short bowel syndrome (SBS) were studied in conscious canines in both acute and chronic phases following 80% massive distal small bowel resection (MSBR). TM was administered orally to beagles with MSBR or as controls in the postprandial and fasting states, and given simultaneously with meals. Intestinal motility was measured using bipolar electrodes for approximately 1 month after the electrodes were implanted in each beagle and the data compared between treatment groups. When TM was given with meals, the postprandial period without duodenal migrating myoelectric (or motor) complexes (MMCs) was shorter than in those given meals only. When TM was given in the postprandial state in short bowel beagles, the initial duodenal MMCs occurred earlier, i.e. the postprandial period was shorter. Diarrhea did not occur in these beagles. When TM was given in the fasting state, duodenal MMCs occurred and propagated to the distal intestine. In conclusion, oral TM administration can produce a more appropriate intestinal condition for the next food intake and make enteral nutrition possible even in the acute phase after MSBR. Such feeding can be carried out without overloading gut function as a result of the modulation of gastrointestinal motility by TM.

Anastomosis, Surgical↗
PubMed1999

Altered myoelectrical activity in noninflamed ileum of rats with colitis induced by trinitrobenzene sulphonic acid.

Changes in gastric emptying and orocaecal transit time in patients with ulcerative colitis suggest that disturbances in gut motility may not be restricted to inflamed sites. This study sought to characterize changes in the motility of noninflamed ileum in a rat colitis model and to explore the mechanism(s) potentially involved. The myoelectrical activity of the ileum was recorded in rats with trinitrobenzene sulphonic acid (TNBS)-induced colitis. The degree of ileal and colonic inflammation was assessed by quantification of macroscopic damage and myeloperoxidase activity (MPO). The effect on ileal motility of pretreatment with atropine, indomethacin and NG-nitro-L-arginine-methyl ester (L-NAME) was investigated. TNBS-induced inflammation was restricted to the distal colon, as evidenced by morphological scores and MPO. Colitis was associated with increased frequency of ileal migrating motor complexes, characterized mainly by a decrease in the duration of phases I and III. The occurrence of ileal giant migrating complexes remained unchanged. The myoelectrical changes observed in the ileum persisted after treatment with atropine, indomethacin and L-NAME. Distal colitis is associated with abnormal myoelectrical activity in the noninflamed ileum of rats. Neither acetylcholine nor prostaglandins and nitric oxide seem to be involved.

Animals↗
PubMed1997

Canine intestinal myoelectric activity after open versus laparoscopically assisted right hemicolectomy.

BACKGROUND: It is a common belief that a laparoscopic procedure results in a shorter duration of postoperative ileus compared with the equivalent open procedure. This study was undertaken to determine whether laparoscopically assisted right hemicolectomy in the dog results in a shorter duration of ileus compared with open right hemicolectomy. METHODS: Eight bipolar serosal electrodes (4 on the small bowel, 4 on the left colon) were implanted in each dog (n = 10). Three weeks after electrode implantation baseline recording was made for 5 days; then 5 dogs underwent laparoscopically assisted right hemicolectomy and 5 underwent open right hemicolectomy. Myoelectric activity was recorded continuously for 72 hours postoperatively. Tracings were analyzed for the time of reappearance, duration, migration velocity, and cycle length of phase 2, phase 3, and the migrating colonic complex. The criteria used for the resolution of postoperative ileus were the return of phase 2, phase 3, and the migrating colonic complex. RESULTS: All dogs had temporary loss of organized myoelectric activity postoperatively. The mean reappearance time (minutes +/- standard deviation) for phase 3 was 857 +/- 574 versus 761 +/- 600; the phase 2 reappearance time was 1,845 +/- 610 versus 1,590 +/- 668; and the migrating colonic complex reappearance time was 534 +/- 365 versus 572 +/- 552, open versus laparoscopically assisted right hemicolectomy, respectively. The times were not different (Wilcoxon rank sum test, P > 0.05). The time required for phase 3, phase 2, and the migrating colonic complex to attain preoperative configuration also was not different between the open and laparoscopically assisted group. CONCLUSION: Myoelectric resolution of postoperative ileus did not occur earlier in the dog undergoing laparoscopically assisted right hemicolectomy compared to the dog undergoing open right hemicolectomy. This data does not support the hypothesis that a laparoscopically assisted colectomy results in a shorter duration of postoperative ileus than the equivalent open procedure.

Animals↗
PubMed1993

Exogenous neuropeptide Y blocks myoelectric activity in the upper gastrointestinal tract of starved dogs. Brain neuropeptide Y converts a fasting pattern of myoelectric activity to a fed pattern.

The effect of intracerebroventricular (ICV) neuropeptide Y (NPY) on the migrating motor complex (MMC) was examined in five starved dogs. Myoelectric activity was recorded using gastric, duodenal, and jejunal electrodes. Intragastric pressure was monitored via a gastric fistula, and ICV injections were given through a cerebroventricular guide. Recordings were made with no ICV injection and before and after 250-microliters bolus injections of vehicle as control (0.1% dog serum albumin in saline) or 500 pmol/kg NPY. The mean interval between MMCs was 98 +/- 10 min without ICV injection and 96 +/- 7 min after control solution. After ICV injection of NPY no further MMCs were recorded in any dog, even though the study was continued for a minimum of 3.5 h. Instead, the myoelectric pattern became indistinguishable from that in fed dogs. We conclude that central NPY plays a role in modulation of upper gastrointestinal myoelectric activity. This may reflect a central regulatory role for NPY in the coordination of feeding.

Animals↗
PubMed2002

Characteristics and cholinergic control of the 'minute rhythm' in ovine antrum, small bowel and gallbladder.

Eight adult conscious rams were used to characterize further the minute rhythm and to determine the role of cholinergic receptors in nervous control of this event. In chronic experiments, the myoelectrical and motor activity of the gastrointestinal tract and gallbladder were recorded. Physiological experiments were performed in fasted or non-fasted rams before, during and after feeding, and the occurrence of minute rhythm during various phases of the migrating motor myoelectric complex was observed. The pattern occurred most frequently in the small intestine, where it exhibited mostly the propagating character. It was also detectable in the ileum. In the gallbladder, the minute rhythm arrived systematically and its character was irregular, propagating, retropropagating or stationary. In all episodes observed, it was well correlated with that in the small intestine. In the pyloric antrum, the minute rhythm was identified occasionally. During pharmacological experiments, 0.15 M NaCl or graded doses of hexamethonium, atropine and pirenzepine were administered intravenously during various phases of the migrating motor myoelectric complex, in fasted and non-fasted animals, before and during feeding. The drugs inhibited the minute rhythm in the small bowel for a longer period than in the gallbladder. However, the smallest dose of pirenzepine (0.02 mg/kg) exerted a non-significant effect both in the small intestine and in the gallbladder. It is concluded, that in normal conditions the minute rhythm occurs regularly in the entire small intestine and in the gallbladder. In the small intestine the pattern is organized more precisely. The minute rhythm is controlled by nicotinic receptors and by muscarinic receptor subtypes.

Animals↗
PubMed1994

Motility of the transplanted small bowel: a manometric study in the piglet.

Complete transection of sympathic and parasympathic nerves is an inevitable consequence of intestinal transplantation. The aim of this experiment was to study if extrinsic denervation alters the motor function of the graft. Ten large-white piglets were used. In Group 1 control (5 animals), a segment of distal ileum was isolated on its intact neurovascular pedicle as a Thirty-Vella loop. In Group 2 study (5 animals), a Thiry-Vella loop of distal ileum was transplanted as a free autograft. The motility of intestinal loops was studied by intraluminal pressure recording at the 8th and 15th postoperative days, on conscious animals fasted for 24 hours. The measured patterns were period (P), duration (D), maximal amplitude (A) and speed of migration (S) of phases III of migratory myoelectric complexes (MMCs). One hundred and seven MMCs were recorded and compared between Group 1 and Group 2. The results were as follows: mean (+/- sem) of Group 1 vs mean (+/- sem) of Group 2. P (min) = 68.5 (+/- 8.1) vs 54.2 (+/- 3.2)(NS); D (min) = 5.9 (+/- 0.2) vs 5.9 (+/- 0.1) (NS); A (cmH2O) = 73.9 (+/- 4.1) vs 83.4 (+/- 3.2) (NS); S (cm/min) = 5 (+/- 1.1) vs 6.2 (+/- 1) (NS). The motor function of the loops was studied following intraluminal perfusion of a cholinergic compound (carbachol) at doses of 1, 2, 3, 4 and 5 mg. The mean and the maximal pressures were recorded during 3 minutes from the 2nd minute following injection of carbachol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Central tumour necrosis factor-alpha mediates the early gastrointestinal motor disturbances induced by lipopolysaccharide in sheep.

Cytokines are involved in fever and other symptoms of the acute phase response induced by endotoxins. The aim of this work was to study the involvement of central tumour necrosis factor-alpha (TNF-alpha) in the changes induced by lipopolysaccharide (LPS) on gastrointestinal (GI) motility in sheep. Body temperature and myoelectric activity of the antrum, duodenum and jejunum was recorded continuously. Intravenous (i.v.) administration of LPS (0.1 micro g kg-1)-induced hyperthermia, decreased gastrointestinal myoelectric activity and increased the frequency of the migrating motor complex (MMC). These effects started 40-50 min after LPS and lasted for 6-7 h. TNF-alpha (50 and 100 ng kg-1) mimicked these effects when injected intracerebroventricularly (i.c.v.) but not i.v. Pretreatment with soluble recombinant TNF receptor (TNFR:Fc, 10 micro g kg-1, i.c.v.) abolished the TNF-induced actions and reduced those evoked by LPS. Furthermore, the effects induced by either LPS or TNF were suppressed by prior i.c.v. injection of indomethacin (100 micro g kg-1). In contrast, the i.v. injections of TNFR:Fc or indomethacin were ineffective. Our data suggest that LPS disturbs GI motility in sheep through a central pathway that involves TNF-alpha and prostaglandins sequentially.

Animals↗
PubMed1997

Recovery of gastrointestinal tract motility and myoelectric activity change after abdominal surgery.

OBJECTIVE: To investigate the relationship between fedstate gastrointestinal tract (GI) function and upper GI myoelectric changes seen after abdominal surgery. DESIGN: Twenty-one adult female mongrel dogs underwent either an open cholecystectomy, a laparoscopic cholecystectomy alone, or a laparoscopic cholecystectomy with peritoneal injury (n = 7 for each group). Bipolar recording electrodes were placed on the antrum and 3 sites of the proximal small intestine to record fasting myoelectric data each morning postoperatively. Solid-phase, technetium Tc 99m gastric emptying studies were performed on postoperative days 1 and 2. Radiopaque markers were ingested just before operation, and the excreted markers were counted using x-ray films of the feces. MAIN OUTCOME MEASURES: Postoperative fasting GI myoelectric activity, gastric emptying, and intestinal transit time. RESULTS: Migrating motor complexes (MMCs) in the small intestine were observed in 33.3% and 75.0% of the dogs on postoperative days 1 and 2, respectively. Gastric dysrhythmias were observed in 23.8% and 45.0% of the dogs on postoperative days 1 and 2, respectively. No relationship between type of surgery and the presence of MMCs or gastric dysrhythmias was noted. Gastric emptying was delayed on postoperative day 1 and was unrelated to the presence of MMCs. Transit time was not significantly delayed in dogs without MMCs on postoperative day 1 compared with that in dogs with MMCs on that day. The presence of gastric dysrhythmias did not affect transit time studies. CONCLUSION: Fasting GI myoelectric activity, including the return of MMCs and the presence of gastric dysrhythmias, does not accurately predict fed-state gastrointestinal GI function following abdominal surgery.

Abdomen↗
PubMed1992

Preservation and propagation of cyclic myoelectric activity after feeding in rat small intestine.

The cyclic nature and distal propagation of the fasting migrating motor complex (MMC) of the small intestine have been well described. The fate of the MMC after feeding, however, has not been elucidated. We used time series analysis with fast Fourier transforms (FFT) to study myoelectric cycling before and after feeding. Ten rats were chronically prepared with bipolar electrodes secured to the duodenum and proximal jejunum. Spikeburst frequency was recorded before and after feeding simple nutrients. During fasting, cyclic activity occurred at the MMC frequency. Although after feeding this periodicity appeared disrupted, FFT analysis showed persistent cycling at the fasted (MMC) rate. Digital filtering of data at the MMC frequency isolated cycling from background noise during both fasted and fed states and showed a depression in the amplitude of the waveform after feeding. Root-mean-square analysis of the waveform confirmed statistically significant depression of amplitude by 47-57%. The waveform propagated from the duodenum to the jejunum during both the fasted and fed state at an unchanged rate. We conclude that factors controlling myoelectric cycling during the fasted state persist after feeding, allowing continued net abroad propulsion of food.

Administration, Oral↗
PubMed2003

Role of duodenum on sphincter of Oddi motility in conscious dogs.

Our aim was to determine the role of the duodenum in controlling sphincter of Oddi motility using conscious dogs after total duodenectomy. In a control group (N = 6), a cannula was implanted into the duodenum opposite to the papilla to allow retrograde sphincter manometry. In a duodenectomy group (N = 6), the papillae were preserved at total duodenectomy and sutured to thejejunum anastomosed to the stomach (neoduodenum). The cannula was implanted opposite to the implanted papillae. Interdigestive and postprandial sphincter and duodental or neoduodenal motility were recorded by manometric and myoelectric methods. Duodenectomy disrupted sphincter cyclic motility associated with the intestinal migrating motor complex and increased sphincter activity throughout the cycle. Sphincter activity increased immediately after feeding and did not differ between the two groups. In conclusion, during the interdigestive period, the duodenum has a distinct role in regulating sphincter cyclic motility. The initiation of the fed pattern of sphincter motility does not need the duodenum.

Animals↗
PubMed2006

Roux-en-Y or 'uncut' Roux procedure? Relation of intestinal migrating motor complex recovery to the preservation of the network of interstitial cells of Cajal in pigs.

We designed a conscious pig model to investigate myoelectric activity and the number of interstitial cells of Cajal (ICC) in the proximal jejunum following the Roux-en-Y and 'uncut' Roux procedures in relation to clinical outcomes. Twelve male Polish White pigs (8 weeks old, 10-13 kg) underwent surgery under general anaesthesia first to implant bipolar electrodes and telemetry transmitters for continuous electromyography recordings and then, after 1 week recovery, to create Roux-en-Y (n = 6) and 'uncut' Roux loops (n = 6). Upper gut tissue specimens were studied for the expression of c-kit staining procedure to quantitatively identify the presence of interstitial cells of Cajal. The intestinal migrating motor complex was restored within 10.5 and 37 h in 'uncut' Roux and Roux-en-Y pigs, respectively (P < 0.05). During 2 weeks, the 'uncut' Roux piglets increased their body weight by 18.0%, whereas the Roux-en-Y piglets increased their body weight by only 7.3% (P < or = 0.05). Two weeks after surgery, the number of ICC located in the region of Auerbach's plexus was higher and adhesions in the abdominal cavity lower in the 'uncut' Roux group. In conclusion, in the pig model, preservation of smooth muscle and ICC network continuity in the proximal jejunum may play an important role in early postsurgical recovery.

Animals↗
PubMed2005

Relationship between dietary-induced changes in intestinal commensal microflora and duodenojejunal myoelectric activity monitored by radiotelemetry in the rat in vivo.

Interdigestive intestinal motility, and especially phase III of the migrating myoelectric/motor complex (MMC), is responsible for intestinal clearance and plays an important role in prevention of bacterial overgrowth and translocation in the gut. Yet previous results from gnotobiotic rats have shown that intestinal microflora can themselves affect the characteristics of the myoelectric activity of the gut during the interdigestive state. Given that the composition of the intestinal microflora can be altered by dietary manipulations, we investigated the effect of supplementation of the diet with synbiotics on intestinal microflora structure and the duodenojejunal myoelectric activity in the rat. To reduce animal distress caused by restraint and handling, which can itself affect GI motility, we applied radiotelemetry for duodenojejunal EMG recordings in conscious, freely moving rats. Thirty 16-month-old Spraque-Dawley rats were used. The diet for 15 rats (E group) was supplemented with chicory inulin, Lactobacillus rhamnosus and Bifidobacterium lactis. The remaining 15 rats were fed control diet without supplements (C group). Three rats from each group were implanted with three bipolar electrodes positioned at 2, 14 and 28 cm distal to the pylorus. After recovery, two 6 h recordings of duodenojejunal EMG were carried out on each operated rat. Subsequently, group C rats received feed supplements and group E rats received only control diet for 1 week, and an additional two 6 h recordings were carried out on each of these rats. Non-operated C and E rats were killed and samples of GI tract were collected for microbiological analyses. Supplementation of the diet with the pro- and prebiotics mixture increased the number of bifidobacteria, whereas it decreased the number of enterobacteria in jejunum, ileum, caecum and colon. In both caecum and colon, the dietary supplementation increased the number of total anaerobes and lactobacilli. Treatment with synbiotics increased occurrence of phase III of the MMC at all three levels of the small intestine. The propagation velocity of phase III in the whole recording segment was also increased from 3.7 +/- 0.2 to 4.4 +/- 0.2 cm min(-1) by dietary treatment. Treatment with synbiotics increased the frequency of response potentials of the propagated phase III of the MMC at both levels of the jejunum, but not in the duodenum. In both parts of the jejunum, the supplementation of the diet significantly decreased the duration of phase II of the MMC, while it did not change the duration of phase I and phase III. Using the telemetry technique it was demonstrated that changes in the gastrointestinal microflora exhibited an intestinal motility response and, more importantly, that such changes can be initiated by the addition of synbiotics to the diet.

Animals↗
PubMed1994

Motility of isolated bowel segment Iowa model III.

The isolated bowel segment (IBS) is an amesenteric segment of bowel that is devoid of extrinsic nerves and yet is viable with motility and absorption preserved after its mesentery is completely severed. The IBS is created by initial coaptation of a loop of bowel to a host organ, such as muscle (Iowa model I), liver (Iowa model II), or intestine, and secondary severance of its mesentery several weeks later. In previous studies using Iowa models I and II, the viability, motility, and absorption of the IBS were preserved by vascular collaterals, which form across the coaptation. In rats, an IBS was created in the jejunum by initial enteroenteropexy (Iowa model III), followed by its mesenteric division five weeks later. At the second laparotomy, bipolar electrodes were implanted in the IBS and the adjacent jejunum. One week later, myoelectrical recording was performed during a fasting state. Coordinated abroad propagation of migrating motor complex (MMC) was observed in the IBS. The MMC period was 16.9 +/- 1.7 and 19.3 +/- 0.8 min in the intact bowel, and 22.8 +/- 0.8 min in the IBS (P = 0.1). After feeding, the MMC in the IBS was replaced by irregular spike burst activity similar to that observed in the intact bowel. This study concludes that the IBS Iowa model III can be used for studies of bowel physiology.

Anastomosis, Surgical↗
PubMed1997

In situ neural isolation of the entire canine upper gut: effects on fasting and fed motility patterns.

BACKGROUND: Multiorgan upper gut transplantation is becoming clinically feasible; however, the effects of multivisceral transplantations on gastrointestinal motility are unknown. Our aim was to determine the neural and hormonal mechanisms controlling motility patterns after complete extrinsic denervation of the upper gut as a model of multivisceral upper gut autotransplantation. METHODS: Seven dogs successfully underwent in situ neural isolation of the stomach, entire small intestine, proximal colon, liver, and pancreas by transecting all connections (distal esophagus, midcolon, all nerves, lymphatics) to this multivisceral complex except the celiac artery, superior mesenteric artery, and the suprahepatic and infrahepatic vena cava; these vessels were meticulously stripped of adventitia under optical magnification. Blood flow was not disrupted to prevent confounding effects of ischemia-reperfusion injury. After 1- to 2-week recovery, myoelectric and manometric recordings of stomach and myoelectric recordings of small bowel were obtained from conscious animals. RESULTS: During fasting the characteristic cycling migrating motor complex (MMC) was observed in the stomach and small intestine. The gastric component of the MMC was absent in one of the seven dogs. Regular cycling of the MMC during fasting, however, was intermittently disrupted and replaced by a noncyclic pattern of intermittent contractions in two of seven dogs 43% of the recording time. A small meal (50 gm liver) did not abolish the MMC as occurs in normal dogs; in contrast, a large meal (500 gm liver) did abolish the MMC. CONCLUSIONS: Extrinsic innervation to the upper gut modulates but is not requisite for interdigestive and postprandial motility of the stomach. Because relatively normal global motility patterns are preserved, multivisceral upper gut transplantation should be a viable option in selected patients.

Animals↗