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PubMed1988

Milk feeding and xylazine treatment induce increased antroduodenal motility in young cattle with opposite effects on duodenal digesta flow rate.

Antroduodenal myoelectrical activity and duodenal digesta flow rate in young cattle were assessed by implanted nichrome wire electrodes and reentrant duodenal cannulation with interposed flow-meter. In addition, a small glass electrode was inserted through a duodenal cannula to continuously measure the pH of duodenal contents. When eating only hay ad libitum, the duodenal myoelectrical activity showed the usual migrating myoelectrical complex (MMC) pattern. Duodenal contents pH rose sharply at the end of a period of repetitive spike activity (RSA), or phase III, from pH less than 2 to greater than 5 and remained high through most of the subsequent period of no spike activity (NSA), or phase I, during which there was no antral spiking and no flow of duodenal contents. Feeding milk (pH 6.5) caused a marked increase in antroduodenal spike activity and intraduodenal flow rate, with a concomitant rapid rise in duodenal contents pH from 1.8 +/- 0.3 (SEM) to 5.0 +/- 0.2 which then slowly declined over the next few hours. Within 5 min after the administration of the alpha 2-adrenergic agonist xylazine (25 and 50 micrograms/kg intramuscular), there was a significant increase (P less than 0.05) in antroduodenal spike frequency and a concomitant marked drop in intraduodenal flow rate with a sustained low pH of intraduodenal contents. The results suggest that: (1) continuous measurement of proximal duodenal pH adds a useful dimension to documenting relationships between antroduodenal myoelectrical activity and duodenal digesta flow rate; and (2) increased spike activity in the antroduodenal region does not necessarily indicate an increased duodenal flow rate is occurring.

Animal Feed↗
PubMed1990

Long-duration stress. Immediate and late effects on small and large bowel motility in rat.

No extensive information exists in literature concerning the late or residual effects of stress on motility of small bowel and colon. Moreover, the duration and magnitude of the intestinal motor response to stress are still ignored. Therefore, the aim of our work was to determine, in rat, the effect of long-duration stress induced by restraint on the motility of small bowel and colon. Observations were made during physical restraint and 60 h later. Bipolar electrodes were implanted on the gastrointestinal serosa from the pylorus to the sigmoid colon in male Wistar rats. Electromyographic (EMG) recordings were made during fasting state, and a control EMG recording session was performed during 12 hr, followed by a 12-hr recording during restraint stress. After a 60-hr resting period, another EMG recording session was performed during 3 hr. During stress in the pylorus and small bowel, the recurrence of migrating myoelectrical complexes (MMCs) was immediately interrupted and replaced by a continuous and irregular activity. The motility index (number of spike bursts/10 min) was augmented rapidly on the jejunum and ileum, but it increased only gradually on the pylorus. Only on the transverse colon were the number of spike bursts/hour and their relative duration increased after 7 hr of physical restraint. In contrast, the sigmoid colon displayed a gradual decrease in the relative duration of contractile activity during the first 6-7 hr of stress. At 60 hr after stress in the pylorus and small bowel, a normal control motor activity was restored (MMC, motility index) on the jejunum and on the ileum, but the motility index on the pylorus was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Long-term effects of jejunoileal autotransplantation on myoelectrical activity in canine small intestine.

We studied the longitudinal effects of autotransplantation on the motor function of the jejunoileum. By performing the autotransplantation procedure in a manner similar to that employed for allotransplantation, we sought to examine the long-term effects of both extrinsic denervation and the operative procedure itself on small intestinal motor function. Although initially disrupted, interdigestive myoelectrical activity demonstrated progressive organization: 88% of migrating myoelectrical complexes in animals studied between 12 and 20 months following autotransplantation demonstrated each phase of the complex in normal sequence. Longitudinal studies of several parameters of myoelectrical activity provided further evidence of progressive organization and entrainment of motor functions within the denervated intestine. Several abnormal myoelectrical patterns were observed within the autotransplanted segment, however, and coordination of either slow wave or phase III activity with the proximal innervated intestine did not recover with time. The major component of the myoelectrical response to feeding was permanently impaired with a delayed onset and shortened duration of the fed response. We conclude that the extrinsically denervated intestine recovers the ability to generate and organize all phases of the MMC but demonstrates permanent impairment of the major motor response to food. However, anoxic and cooling damage to enteric nerves and muscle, incurred during the autotransplantation procedure, may explain the persistence of abnormal motor patterns and impaired myoelectrical conduction and could play an important role, additional to that of extrinsic denervation, in the long-term motor function of the allotransplanted intestine.

Animals↗
PubMed1984

Effects of ranitidine and oxmetidine on gastrointestinal motility in conscious dog.

Two histamine H2-receptor antagonists ranitidine and oxmetidine were tested for their effects on gastrointestinal motility in conscious fasted dogs chronically fitted with intraparietal electrodes on the antrum, duodenum and jejunum. Intravenous administration of ranitidine (3 mg/kg) stimulated gastrointestinal spiking activity through a cholinergic mechanism and increased the duration of the cycles of migrating myoelectric complexes. Oxmetidine at the same dose did not modify the gastrointestinal motor profile. These results showed clearcut differences in nonspecific effects of two H2-antagonists equipotent on gastric acid secretion.

Animals↗
PubMed1981

Is there a functional large intestine in the ferret?

The intestine of the ferret (Putorius furo) is unusual in that there is no external anatomical division between ileum and colon. Up to 8-10 cm from the anus the electrical activity was organized into migrating myoelectric complexes typical of the small intestine. At this point the pattern of electrical activity changed abruptly to that characteristic of the colon, namely short and long spike burst activity. Histological examination showed that at this point the muscular layers were interrupted by a band of connective tissue sufficient to permit the functional autonomy of the last part of the intestine.

Animals↗
PubMed1991

Myoelectric intestinal disturbances in Escherichia coli endotoxic shock in rats. Involvement of platelet-activating factor.

Administration of BN 52021 (50 mg/kg i.v.), a specific antagonist of platelet-activating factor (PAF), significantly reduced the intestinal myoelectric disturbances induced by E. coli endotoxin injection (50 micrograms/kg i.v.) by 62%. Thus, PAF may be involved in the intestinal motor alterations observed in endotoxic shock. When given in combination with indomethacin (10 mg/kg i.p.), BN 52021 inhibited endotoxic shock intestinal disturbances. Indomethacin alone also reduced PAF induced (25 micrograms/kg i.p.) disruption of migrating myoelectric complexes. Endotoxins may act on intestinal motility via release of endogenous PAF and prostaglandins, the effects of PAF being mediated through the release of prostaglandins.

Animals↗
PubMed2003

The influence of surgery, immunosuppressive drugs, and rejection, on graft function after small bowel transplantation: a large-animal study.

In this study we assessed functional changes (motility and absorption) of intestinal allografts in a large-animal model of orthotopic small bowel transplantation in swine. Studies were performed on non-rejecting animals in the early and late stages after transplantation and after induction of different grades of acute rejection. Immunosuppression consisted of oral FK506 and mycophenolate mofetil. In each study group we regulated drug administration, in terms of dosage and timing, in order to induce different grades of acute rejection or to prevent it. Migrating myoelectrical complexes were recorded in fasting animals so that motility could be assessed. Mucosal biopsy of the allograft and D-xylose absorption tests were performed on the same day as the motility study. In the early stages following intestinal transplantation, we observed in non-rejecting animals a slightly increased graft motility and a marked carbohydrate malabsorption. Recovery of the carbohydrate absorption capacity occurs within 2 months, but the persistence of diarrhea leads to partial malabsorption and to a lack of normal weight gain. Motility reduction correlates with the grade of acute rejection and becomes significant at a later stage, when rejection is severe. Allograft carbohydrate absorption, on the contrary, is markedly reduced in all rejecting pigs, irrespective of the grade of rejection. In summary, the early functional impairment of non-rejecting animals has multifactorial causes due to surgery and immunosuppression (drug toxicity), and its occurrence suggests the need for specific guidelines for clinical early postoperative enteral feeding. The functional studies adopted here are helpful in defining the grade of functional impairment with or without acute rejection; however, they are not useful for early detection of ongoing acute rejection of the small bowel graft.

Acute Disease↗
PubMed1997

Role of peptide YY in regulation of duodenal motility during the interdigestive period in sheep.

Temporal coordination between duodenal migrating myoelectric complexes (MMC) and pancreatic exocrine secretion, and the effects of porcine peptide YY (PYY) on gastroduodenal motility and pancreatic exocrine secretion were examined during the interdigestive period in conscious mature sheep. Fluid and enzyme secretions from the exocrine pancreas showed a periodic pattern corresponding to the phases of duodenal MMC, although these secretion rates were maintained at a high level during phase II in sheep. Intravenous continuous infusion of PYY at doses ranging from 50 to 200 pmol.kg-1.h-1 or intravenous bolus infusion of PYY at doses ranging from 50 to 200 pmol.kg-1 showed a tendency to prolong the first cycle of the duodenal MMC and significantly shorten the second cycle. However, there was almost no effect on ruminal contractions from the PYY administration. In the pancreatic exocrine secretion, PYY could inhibit only bicarbonate secretion at only the highest dose of 200 pmol.kg-1. These results imply that endogenous PYY may play a physiological role in the regulation of the duodenal MMC cycles in sheep but not in ruminal contractions. PYY seems unlikely to regulate the pancreatic exocrine secretion in normal sheep, because a supraphysiological dose of PYY was required to inhibit the pancreatic exocrine secretion.

Amylases↗
PubMed2001

Does loperamide affect motor activity after proctocolectomy and ileal pouch-anal anastomosis? An experimental study in dogs.

This study investigated the effect of loperamide on the motor function of small intestine and J-pouch. Proctocolectomy and ileal pouch-anal anastomosis were performed in four dogs. Motility was recorded by serosal electrodes and strain gauge transducers. The intestinal transit time was determined radiologically. Multiple measurements were performed before and during chronic administration of loperamide. This treatment led to a significant decrease in median stool frequency from 11 (10-13) to 9 stools/day (8-12) and a tendential increase in intestinal transit time from 60 (50-105) to 70 min (60-90). This was not accompanied by significant changes in fasted or postprandial motility. There were no significant differences in the characteristics of the migrating myoelectric complex or in the fed pattern, either in the small intestine or in the pouch. Loperamide thus does not significantly affect intestinal motility after ileal pouch-anal anastomosis. The reduction in stool frequency seems to be due to antisecretory effects in the first line.

Animals↗
PubMed1990

CCK8 neurons of the ventromedial (VMH) hypothalamus mediate the upper gut motor changes associated with feeding in rats.

The effect of microinfusions of cholecystokinin octapeptide (CCK8) and its antagonist L364,718 on duodenal and jejunal motility were evaluated by electromyography in fasted and fed rats. The rats were chronically fitted with electrodes implanted on the duodeno-jejunal wall. Steel cannulas were placed bilaterally in either the ventromedial (VMH) and lateral (LHA) hypothalamus. In 8 h fasted rats, microinfusion of CCK8 (1 ng/kg) into the VMH disrupted the migrating myoelectric complex (MMC) and replaced it by irregular spiking activity for 45.0 +/- 4.9 min at the duodenal level without affecting the jejunal MMC pattern. The duration of these effects were dose-related between 1 and 50 ng/kg. When injected into the LHA at 1, 10 or 50 ng/kg, CCK8 had no effect on either duodenal or jejunal motility. When infused bilaterally into the VMH 10 min before feeding, L364,718 (1 or 10 micrograms/kg) significantly reduced the duration of the postprandial disruption of MMCs by 29.1% and 35.9%, respectively, in the duodenum but not the jejunum (P less than 0.05). Infused into the LHA at similar and higher dosages (1 and 10 micrograms/kg) L364,718 had no effect on the duration of the duodeno-jejunal fed pattern. These results suggest that, in rats, (i) CCK8 is involved in the maintenance of the typical postprandial disruption of duodenal MMCs observed after a meal, and (ii) these effects are selectively mediated through CCK8 receptors located in the ventromedial hypothalamic nuclei.

Animals↗
PubMed1990

Pertussis toxin modifies the effect of central morphine on rat intestinal motility.

To find whether the antipropulsive effect of morphine administered intracerebroventricularly (i.c.v.) depends on a G-protein-mediated mechanism, we studied the effect of i.c.v. pertussis toxin (PTX) pretreatment on morphine-induced inhibition of intestinal motility. The influence of PTX was evaluated on intestinal transit (charcoal meal test) and by monitoring of intestinal myoelectrical activity. The antitransit effect of morphine (10 micrograms/rat) was antagonized by about 70% 3, 6, 9 and 12 days after PTX pretreatment (1 microgram/rat) and it was partially restored after 25 days. I.c.v. morphine abolished the regular appearance of the myoelectric migrating complex (MMC) recorded in the rat jejunum and this effect was completely antagonized by PTX pretreatment. When morphine was injected 25 days after PTX, it significantly reduced MMC frequency, confirming the partial recovery seen in the transit experiments. The pertussis toxin-catalyzed ADP ribosylation of a 39-41 kDa substrate in membranes prepared from hypothalamus and midbrain of rats injected with toxin 6 days before was strongly reduced as compared to the controls. On the contrary, after 25 days, ADP ribosylation was the same in treated and control rats. Thus the antipropulsive effect of central morphine could be initiated at receptor sites which interact with G-protein substrates of pertussis toxin.

Adenosine Diphosphate↗
PubMed1987

Altered small bowel motility in irritable bowel syndrome is correlated with symptoms.

The pathogenesis of irritable bowel syndrome (IBS) has been related more to dysmotility of the colon than to abnormalities of the small intestine. To look for small bowel abnormalities, we recorded ultraluminal pressures in 16 patients with IBS. All patients complained of abdominal pain, and diarrhea (n = 8) or constipation (n = 8) were also prominent symptoms. Comparable studies were performed on 16 age-matched controls. The observations include diurnal and nocturnal fasting recordings and the response to a fatty meal. Periodicities of the interdigestive migrating myoelectric complexes were shorter in IBS (p less than 0.05); this was due to much shorter diurnal cycles in patients with diarrhea (77 +/- 10 min) than those with constipation (118 +/- 15 min) or controls (113 +/- 10 min, both p less than 0.05). All groups exhibited circadian changes, with nocturnal cycles being more frequent. Two specific patterns of small bowel motor activity were more common in IBS--ileal propulsive waves and clusters of jejunal pressure activity (both p less than 0.05 compared to controls). Moreover, cramping abdominal pain was usually noted in IBS when ileal motility was propulsive; jejunal bursts were also sometimes associated with abdominal symptoms. We conclude that motility of the small intestine is modified in some patients with IBS and that certain motor patterns are related to their symptoms.

Abdomen↗
PubMed1993

Central action of interleukin 1 beta on intestinal motility in rats: mediation by two mechanisms.

BACKGROUND: Interleukin 1 (IL-1) can influence gut functions by inhibiting gastric acid secretion. This study was performed to investigate the effects of IL-1 on intestinal motility and the mechanisms involved. METHODS: The effects of IL-1 beta were determined by electromyography in conscious rats with implanted electrodes and a permanent catheter in a lateral brain ventricle. RESULTS: Intracerebroventricular IL-1 beta (15 ng) administered to fed rats immediately stimulated cecocolonic spike bursts and caused a migrating myoelectric complex pattern after a delay in the small intestine. Tenfold higher doses of peripherally administered IL-1 beta did not promote similar reactions. The IL-1 antagonist reduced the small intestinal effect of IL-1 beta and blocked the cecocolonic stimulation. Indomethacin and SC 19220 reduced the small intestinal effects but did not antagonize the increase in cecocolonic contractions. In contrast, alpha-helical CRF9-41 blocked the increase of cecocolonic contractions but did not antagonize the IL-1 beta-induced effects on the small intestine. CONCLUSION: IL-1 beta's effects on intestinal motility can be mainly ascribed to a central action. The cecocolonic stimulation may be mediated by brain corticotropin-releasing factor, whereas the small intestinal effects involve a prostaglandin mediation.

Animals↗
PubMed1993

Fedotozine reverses ileus induced by surgery or peritonitis: action at peripheral kappa-opioid receptors.

BACKGROUND: Fedotozine is a peripheral opioid agonist. Its effects were assessed in experimental ileus in rats. METHODS: Ileus was induced by abdominal surgery (laparotomy and cecum palpation) or peritonitis (acetic acid, intraperitoneally). Digestive motility was recorded by electromyography and gastrointestinal transit estimated using a 51Cr-labeled test meal. RESULTS: Surgery or peritonitis inhibited motility and migrating myoelectrical complexes for 2-3 hours. In both models, fedotozine (3 mg/kg, intravenously; 10 mg/kg, subcutaneously) restored a normal motility pattern. This action was reproduced by the kappa-agonist, U-50, and 488H and was blocked by subcutaneous naloxone, naloxone-methiodide, or nor-binaltorphimine, a selective kappa-antagonist. Peritonitis induced a 57% inhibition of gastric emptying and intestinal transit that was reversed by fedotozine (1-10 mg/kg, subcutaneously) or kappa-agonists (U-50, 488H, bremazocine) but not delta-agonists (DPDPE, [D-Ala2]-deltorphin-II), whereas mu-agonists (morphine, fentanyl) potentiated ileus. Fedotozine restoration of transit was blocked by subcutaneous naloxone, naloxone-methiodide, or norbinaltorphimine but not by intracerebroventricular naloxone. Fedotozine was inactive up to 300 micrograms/rat when given intracerebroventrically or intrathecally. CONCLUSION: Fedotozine reverses experimental ileus via an action at peripheral kappa-opioid receptors.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1988

Quantitative analysis of intestinal electrical spike activity by a new computerized method.

We developed a computerized method that allows quantitative analysis of intestinal spike activity. This method was tested for a series of measurements in six fasting conscious dogs, fitted with bipolar electrodes chronically implanted along the small intestine. Data were stored on 8-channel tape recordings and digitized before computer processing. Spike detection was accomplished by means of a discriminant function able to differentiate spikes from non-spikes (e.g. artifacts) on the basis of six parameters. Computer analysis allowed accurate spike recognition (probability of incorrect classification less than 6%). Spike activity during fasting was monitored by calculating, during each phase of the migrating myoelectric complex, the following parameters per unit of time (30 s): number of spikes, percentage of spiked slow waves and number of spikes per spiked slow wave. Results were given both in tabular and graphical form. This method provides a research tool for a better quantitation of intestinal spike activity.

Action Potentials↗
PubMed1990

The newborn piglet: a model of neonatal gastrointestinal motility.

Small intestinal myoelectric activity has been studied extensively in adult humans and in many animal models. However, little is known about gut myoelectrical activity in newborns, a population susceptible to primary and secondary motility disorders. We report the development of a chronic neonatal piglet model for assessment of gastric and small intestinal myoelectric activity. Six piglets aged 12 to 27 days and weighing 2.3 to 4 kg underwent laparotomy and implantation of four to six bipolar serosal electrodes along the small intestine; and selectively on the gastric antrum. Myoelectric records were obtained daily after operation in awake animals using low (0.16 Hz) and high (30 Hz) frequency filters. Electrical control activity (ECA) was observed in the stomach (4 to 5 cycles per minute) and in the duodenum (14 to 15 cycles per minute) on postoperative day 1; along with random bursts of spiking activity. The migrating myoelectric complex (MMC) appeared on postoperative day 2 or 3. In piglets followed for a week or more, the MMC cycle duration and phase III duration (period of maximal spiking activity) were longer in the proximal small intestine than at the terminal ileum (80 +/- 5 versus 47 +/- 3 minutes and 5.1 +/- 0.3 versus 3.7 +/- 0.1 minutes, respectively; mean +/- SEM, P less than .005), suggesting that some MMCs arise spontaneously in the distal small bowel without traversing the upper intestine. The antral and duodenal ECA frequencies are similar to values reported in human adults; the MMC cycle duration is slightly shorter.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effect of alcohol on cyclical myoelectric activity of the opossum sphincter of Oddi.

Ethyl alcohol may adversely affect pancreatic function by perturbing sphincter of Oddi (SO) or duodenal motor activity. The aim of this study was to identify the effect of ingested alcohol on the SO, duodenal, and gastric myoelectric activity in conscious opossums. In five adult opossums bipolar stranded stainless-steel wire electrodes were implanted on the SO, gastric antrum, and duodenum. After a 2-week recovery period, each animal underwent eight 8-hr recording sessions while fasted and awake. After two fasting cycles of the migrating myoelectric complex, animals were randomly fed either 10 ml of a 30% ethyl alcohol solution or 10 ml of water via an esophageal tube, and recordings continued for 4-6 hr. During the control state, cyclical myoelectric spike activity was recorded from the SO, gastric antrum, and duodenum with a mean +/- SD cycle length of 7.35 +/- 15.0 min, 74.3 +/- 10.1 min, and 94.8 +/- 8.7 min, respectively. With alcohol, SO and duodenal cycle lengths were unchanged while gastric cycle length decreased. However, alcohol effected a significant increase in peak SO spike burst frequency with no corresponding change in gastric or duodenal spike burst frequency. An equivalent volume of water had no influence on sphincter of Oddi myoelectric activity. It is concluded that ingested alcohol induces increased myoelectric activity from the opossum SO, independent of changes in activity of the duodenum or stomach. Since the SO plays a major role in metering bile and pancreatic flow into the duodenum, this may be a factor in alcohol-induced pancreatitis.

Ampulla of Vater↗