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Results for “Myoelectric Complex, Migrating”

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PubMed1975

[Electromyographic analysis of motor perturbations linked with gastrointestinal strongyloidiasis].

The effects of experimental infection of lambs with third stage Trichostrongylus larvae are described. Preceding diarrhea, disturbances in the motility of the reticulum, abomasum and jejunum were observed by electromyography. Disappearance of the migrating myoelectric complexes occurred about 24 h before diarrhea and was accompanied by a decrease in both the frequency of reticular contractions and of contractions propagated through the antro-duodenal junction. The significance of these findings is discussed and compared with natural infestation in the field.

Animals↗

PubMed1992

Effects of general anesthesia on myoelectric activity of the intestine in horses.

Myoelectric activity was monitored from the terminal ileum, cecum, and colonic pelvic flexure by use of AgpAgCl bipolar electrodes in 4 adult horses before, during, and after general anesthesia. Horses were anesthetized by way of 3 commonly used regimens, including xylazine (1.1 mg/kg of body weight) and ketamine hydrochloride (2.2 mg/kg); thiopental sodium (7.7 mg/kg), followed by halothane vaporized in oxygen; and thiopental sodium (2.5 g) in guaifenesin (100 mg/ml) solution given to effect, followed by halothane in oxygen. All 3 anesthetic regimens decreased intestinal spike-burst activity in the areas monitored. The slowest return to preanesthetic myoelectric activity was observed after xylazine and ketamine administration. After both of the barbiturate/halothane anesthetic regimens, there was a rebound increase in spike-burst frequency, without alteration in the proportion of propagative myoelectric events. All 3 anesthetic regimens appeared to reset the timing of the small and large intestinal migrating myoelectric complexes. By 9 hours after recovery from anesthesia, the effects of anesthesia, irrespective of regimen, had disappeared. Although anesthesia significantly (P less than 0.05) altered intestinal myoelectric activity, no particular anesthetic regimen had a prolonged effect. Results of our study indicate that the particular chosen regimen of general anesthesia is unimportant in development of motility disturbances in horses after anesthesia.

Acepromazine↗

PubMedDate not supplied

Ovine model for clear-cut study on the role of cholecystokinin in antral, small intestinal and gallbladder motility.

Cholecystokinin (CCK) is one of the major gastrointestinal hormones involved in the control of digestive tract and gallbladder motility. Its action involves several mechanisms. The ovine model was developed in order to further explore the role of CCK in gastric, small intestinal and gallbladder motility under various experimental conditions. Five Merino sheep were used with bipolar electrodes implanted to their antrum, entire small intestine and gallbladder as well as strain gauge force transducers were attached to the duodenum and gallbladder fundus, near the electrodes. In the course of chronic experiments, the myoelectric and motor activity were recorded by means of the adapted electroencephalograph. Among the variety of CCK-octapeptide or cerulein doses, three doses of each CCK peptide were selected and then applied for various time periods. Finally, the effects of the hormones administered within 30 s during phase 2 of the same or different migrating myoelectric complexes (MMCs) on gastrointestinal and gallbladder myoelectric and motor activity were studied in fasted and non-fasted animals. Injection of the highest dose inhibited rumination in four of the five sheep and inhibited phase 3 MMC in the antroduodenal region. Hormone administration inhibited dose-dependently antral myoelectric activity. The effects of moderate dose of both CCK peptides on myoelectric activity of the duodeno-jejunum was usually opposite (i.e. stimulatory) than that of the ileum. Gallbladder response to CCK peptides exhibited mostly the tonic character, and in some experiments, the slow wave frequency and amplitude were altered. It is concluded that CCK acts on several targets and different mechanisms underlie its multiple actions on gastrointestinal and gallbladder motility in sheep.

Action Potentials↗

PubMed1978

[Central origin on the excito-motric action of morphine on intestine].

In ewew fitted with a cerebro-ventricular cannula and equipped with extra-cellular bipolar electrodes on the antrum and proximal small intestine, an intraventricular injection of morphine at a dose (40 micrograms/kg) ineffective peripherally was followed within 1 min by an increased spike activity of the duodenum without disruption of the occurrence of migrating myoelectric complexes. This effect was paralleled by a reduction of antral motility and abolished by small intraventricular doses of nalorphine. After an intravenous injection of large doses of the drug drug (0.8 mg/kg), spike activity was increased at both jejunal and duodenal level without changes in the antrum and followed by a long-lasting disorganization of the motor profile. The results suggested a centrally mediated gastro-duodenal effect of morphine.

Animals↗

PubMed1991

[Postoperative small intestinal motility after abdominal surgery].

After abdominal surgery there is a postoperative small bowel ileus. We evaluate whether the duration of the small bowel ileus is depending on the kind of surgery or not. Over a needle catheter jejunostomy a 3-tip transducer was placed into the distal jejunum. At the end of the operations a pressure detector was connected to measure the intraluminal pressure continuously over five days. Group A consisted of three patients undergoing explorative laparotomy because of inoperable gastric cardia cancer, and group B of eight patients who underwent gastrectomy. In none of the patients a normal empty stomach motility pattern, determined by the activity of a migrating myoelectric complex (MMC) was detectable. In group A the normal MMC-activity returned after 24 +/- 4.5 h and in group B after 82 +/- 25 h. Therefore the duration of the loss of the interdigestive myoelectric complex appeared to be dependent upon the type of surgery.

Cardia↗

PubMed1991

Relationship between the spike activities of the small and large intestines.

Experiments were performed using chronically implanted electrodes on the dog smooth muscle wall of the stomach and of the small and large intestines. Electrical activity of the muscle wall was recorded before and after feeding. When reaching the terminal ileum the active part of the migrating myoelectrical complex (MMC) continuously induced bursts of spike potentials superimposed on the slow waves. This electrical activity spread to the ascending colon. We also showed the existence of a spike activity on the terminal ileum independent of the MMC (appearing during the phase 1) and propagating to the colon. A relationship between the spike activities of the small and large intestines was also present after feeding. Beside the well-known gastro-colic reflex, we observed an increase in the spike activity of the terminal ileum and ascending colon between the 4th-5th hours after feeding. This probably corresponds to the arrival of the first portions of contents, evacuated from the arrival of the first portions of contents, evacuated from the stomach, and of the last portions of small intestinal contents. In conclusion, there is a relationship between the spike activities of the small and large intestines in starving animals and after feeding, and the terminal ileum plays a substantial role in this relationship.

Action Potentials↗

PubMed1990

[Inhibition of the interdigestive myoelectric cycles in dogs by a single administration of bile acids into the branch of the cranial mesenteric artery].

Experiments were performed on 10 fasted dogs equipped with perfused catheter which was placed into the branch of the cranial mesenteric artery supplying the short duodenal or jejunal segment. In addition, 9 bipolar electrodes for electromyographic examinations were implanted into the stomach and small bowel including the perfused intestinal segment. Na-taurocholate, Na-taurodeoxycholate (TD) and Na-taurochenodeoxycholate were infused for 2 hr in 2 different doses (reaching in blood, which supplies the intestine, the concentration about 7.5 and about 50 mumol.l-1) or injected for 0.5 min (reaching the concentration about 200 mumol.l-1 in the blood) close intraarterially to the animals. The lower dose of bile acid infused caused no significant changes in myoelectric activity. The higher dose of bile acid infused significantly inhibited the occurrence of action potentials (prolongation of phase I of the migrating myoelectric complex) for the period much longer than the bile acid infusion itself. Both stimulatory (the phase III-like myoelectric activity, vomiting) and inhibitory effects of action potentials as well as changes in frequency and amplitude of resting potentials were triggered by bile acid injection. Alterations induced by TD administration were the strongest. The immediate appearance of the inhibitory effect suggests the mediatory role of the nervous system in this response. In normal conditions the bile acids appear to regulate the motor function of the digestive tract solely when they enter the intestinal lumen. Their raised level in plasma, as observed in many liver and biliary tract diseases must give, as a consequence, an unfavourable effects which may be a cause for the arrival of gastrointestinal manifestations (the motor component) during a course of above affections.

Animals↗

PubMed1990

[Myoelectrical appraisal of the operative procedure with preservation of the right gastroepiploic neurovascular peduncle in selective gastric vagotomy plus antrectomy].

The purpose of this study is to investigate movements of residual stomach after selective vagotomy plus antrectomy (SVA). Electromyograms (EMGs) were recorded chronically from the stomach and intestine of unanesthetized mongrel dogs using 4 different procedures: (1) sham operation (control), (2) SVA with preservation of right gastroepiploic neurovascular peduncle (SV+A'), (3) SVA with peduncle transected (SV+A) and (4) antrectomy alone. The results were as follows: 1. Migrating myoelectric complex (MMC) appeared less in SVA dogs, while frequency of basic electric rhythm (BER) with spike potentials (SP) per MMC period in the duodenum was normally maintained in SV+A'. 2. Postprandial ectopic excitation occurred in SVA, but less frequently in SV+A' than SV+A. SV+A' dogs showed a slower propagation of BER than control, but percent changes from the control nearly equaled that of antrectomized dogs, while in SV+V it was more slowed. 3. Under insulin hypoglycemia, occurrence of BER with SP was normally maintained in SV+A' dogs, but in SV+A it had apparently decreased, suggesting that the cholinergic nerve fiber was in the peduncle. A comparative study was also made of EMG responses to insulin hypoglycemia among SV+A' dogs. The results suggested posterior vagal truncus carries cholinergic fibers to the right gastroepiploic nerve. In conclusion, preservation of the right gastroepiploic neurovascular peduncle had the advantage of preventing the retention of gastric contents following SVA.

Animals↗

PubMed1990

Altered motility and bacterial flora after functional end-to-end anastomosis.

The functional end-to-end technique with a gastrointestinal stapler is commonly used for small-bowel anastomosis, but the effects of this anatomically side-to-side anastomosis on motility are unknown. Fasting small-bowel myoelectric activity and culture results were compared in six animals undergoing handsewn end-to-end and functional end-to-end anastomoses. Serosal electrodes were placed at 10 cm intervals, and the small bowel was divided 25 and 55 cm from the ligament of Treitz. The functional end-to-end and end-to-end techniques were performed in each animal in random order. Fasting myoelectric recordings were obtained at weekly intervals for up to 20 weeks after operation. New electrodes were placed, and additional recordings were obtained from 29 to 39 weeks, 51 to 63 weeks, and 108 to 112 weeks after operation. The recordings were visually inspected for passage of phase 3 of the migrating myoelectric complex (MMC). By 12 to 20 weeks after operation, 91% of MMCs crossed the end-to-end anastomoses versus 22% across the functional end-to-end anastomosis (p less than 0.001). Even 2 years after surgery only 56% of MMCs crossed the functional end-to-end anastomosis. Quantitative bacterial cultures suggested a trend toward bacterial overgrowth in the functional end-to-end anastomosis. These results demonstrate that the functional end-to-end anastomosis alters small-bowel motility to a greater degree than an end-to-end anastomosis and may predispose to bacterial overgrowth.

Anastomosis, Surgical↗

PubMed1989

Ectopic jejunal pacemakers and enterogastric reflux after Roux gastrectomy: effect of intestinal pacing.

The aims of this study were to determine whether ectopic pacemakers are present in the Roux limb of dogs after vagotomy and Roux gastrectomy, whether these pacemakers lead to enterogastric reflux, and whether abolishing the pacemakers with electric pacing might correct such reflex, were it to occur. In five dogs that had undergone gastric vagotomy and Roux gastrectomy and five dogs that had undergone gastric vagotomy and Billroth I gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was recorded during saline infusion (154 mmol/L NaCl) or nutrient (Meritene) infusion into the limb or the duodenum. Reflux of infusate into the stomach was determined via a gastric cannula. Tests in Roux dogs were done with and without limb pacing. Roux dogs showed ectopic pacemakers in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 76% of the recordings; Billroth dogs rarely had such pacemakers (p less than 0.001). Enterogastric reflux occurred in both groups of dogs but was greater during phase III of the interdigestive migrating myoelectric complex in Roux dogs (12% +/- 6%) than in Billroth dogs (3% +/- 1%; p less than 0.05). Pacing abolished the ectopic pacemakers in the Roux dogs and reduced enterogastric reflux from 12% +/- 6% to 3% +/- 2% when phase III was present (p less than 0.05). In conclusion, the Roux limb was driven by ectopic pacemakers that contributed to, but were not solely responsible for, jejunogastric reflux. Pacing abolished the ectopic pacemakers and decreased reflux when phase III was present in the limb.

Action Potentials↗

PubMed1989

[Are intraluminal electrodes reliable for recording myoelectric activity of the small intestine?].

In humans except for the postoperative state, electromyographic activity of the small bowel can only be recorded with intraluminal electrodes. The aim of this study was to validate the use of intraluminal electrodes in pigs by comparing the signal recorded from such electrodes to those recorded with surgically implanted electrodes. A polyethylene probe equipped with bipolar ring-shaped electrodes was placed in the lumen of the proximal jejunum of 6 pigs, at the same level as intramuscular implanted electrodes. The signals were recorded in conscious pigs fed normally. By comparison to the myoelectric activity recorded from the intramuscular implanted electrodes, the intraluminal electrodes provided reliable spike burst detection (sensitivity 85 p. 100; positive predictive value 91 p. 100) in the fasted and fed state, and good identification of migrating myoelectric complexes. Spectral analysis showed the same frequency patterns for signals obtained with both types of electrodes. In conclusion, intraluminal ring-shaped electrodes allow reliable detection of small bowel myoelectric activity and may represent a useful tool for motility studies in man.

Animals↗

PubMed1986

Effects of cholinergic blockade, adrenergic blockade and sympathetic denervation on gastrointestinal myoelectric activity in guinea pig.

Gastrointestinal myoelectric activity was recorded from conscious guinea pigs using sets of bipolar electrodes that had been surgically implanted onto the serosal surface of the gastric antrum or small intestine. The role of nerves in the control of the migrating myoelectric complex (MMC) was investigated using cholinergic and adrenergic receptor antagonists, guanethidine to block sympathetic transmission, reserpine to deplete intestinal monoamines and 6-hydroxydopamine (6-OHDA) to produce chemical sympathectomy and surgical sympathetic denervation of the stomach and small intestine. Subcutaneous infusion of hyoscine (1.0 or 3.0 mg/kg and 1.0 or 3.0 mg/kg/hr) blocked the initiation of phase 3 of the MMC. In the presence of hyoscine, intermittent electrical spiking comparable to that of phase 2 of the MMC was recorded. Hexamethonium infusion (3.0 or 10.0 mg/kg and 3.0 or 10.0 mg/kg/hr) also blocked the initiation of phase 3 and reduced the frequency of the intermittent spiking activity. Acute blockade of adrenergic receptors by simultaneous s.c. infusion of phentolamine and propranolol (1.0 mg/kg and 1.0 mg/kg/hr of each drug) did not alter the MMC, whereas infusion of guanethidine (3.75 or 7.5 mg/kg and 3.75 or 7.5 mg/kg/hr) increased the frequency of the MMC by significantly shortening the duration of phase 2. Sympathetic denervation of the stomach and small intestine did not block the MMC but decreased the cycle frequency by significantly prolonging the duration of phase 2. Chemical sympathectomy using 6-OHDA treatment (3 X 250 mg/kg s.c.) also did not abolish the MMC but decreased the frequency by increasing the duration of phase 2. Reserpine treatment (2.5 mg/kg s.c.) decreased the frequency of the MMC to a greater extent than that produced by 6-OHDA treatment. Histochemical and immunohistochemical evaluation of tissues taken from denervated, 6-OHDA- and reserpine-treated animals confirmed that surgical denervation removed sensory and adrenergic nerves to the stomach and small intestine, whereas chemical sympathectomy affected only adrenergic neurons. Reserpine treatment depleted norepinephrine from extrinsic adrenergic neurons and also depleted 5-hydroxytryptamine from intrinsic intestinal neurons. In the guinea pig, antral myoelectric activity is briefly inhibited during duodenal phase 3. Gastric inhibition persisted during duodenal phase 3 in surgically denervated animals, in 6-OHDA-treated animals and in animals treated acutely with guanethidine. These results indicate that extrinsic sensory and sympathetic nerves are not required for the initiation and propagation of the MMC in the guinea pig small intestine.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗

PubMed1986

[Physico-chemical stimulation of dietary origin and digestive motility in the rabbit].

The effects on gastrointestinal motility of two different diets, one containing dehydrated lucerne and the other dehydrated beet pulp (both being either coarsely or finely ground before pelleting) were studied in 16 unanesthetized 50-60-day old rabbits fed ad libitum. The rabbits fed with lucerne had better antroduodenal and ileo-caecal coordination, a higher level of electrical activity on the duodenum, and more frequent migrating myoelectric complexes on the jejunum and ileum than those fed with beet pulp. Furthermore, the rabbits fed the finely ground pellets showed weak electrical activity on the ileum and poor ileo-caecal coordination irrespective of fiber source, suggesting a unique effect of size per se on these portions of the digestive tract.

Animals↗

PubMed1988

Babesia major: abomasal transmural potential difference, and antroduodenal motility changes associated with experimental infection in calf.

Transmural potential difference, pH and ionic concentrations of the abomasal contents were measured in three calves. Antroduodenal motor patterns were recorded using electrodes and strain-gauge transducers fixed on the antrum and the duodenum. The calves were infected with 8 x 10(9) Babesia major intravenously and a significant drop in transmural potential difference, concomitant with a steady increase in Na+ and K+ concentrations of the abomasal contents occurred within 2 days. The onset of fever on the 5th day after infection was associated with an increased frequency of duodenal migrating myoelectric complexes and episodes of bradygastria on the distal antrum. These changes disappeared at the end of fever. We conclude that transmural potential difference changes and Na+-K+ concentrations in the abomasal fluid could reflect changes in the ionic permeability of the gastric wall. These effects may represent early signs of Babesia infection.

Abomasum↗

PubMed1988

[Effect of liver bile on interdigestive electric activity of the stomach and small intestine in dogs].

Utilizing the chronic experimental dog model the effect of intraduodenal administration of bile upon the interdigestive electric activity of the stomach and small intestine was examined. For this purpose the functional cholecystectomy was performed and common bile duct was cannulated with two catheters. Tubes connected over the skin allowed spontaneous bile circulation during control experiments and in between the experimental periods. Nine pairs of electrodes were implanted into the stomach and small intestinal wall for electromyography. During other experiments standard bile was infused intraduodenally at the rate 0.5 ml.min-1 for 300 min and whole hepatic bile was introduced at the rates 2 ml.min-1 for 60 min and 30 ml.min-1 for 2 min. Hepatic bile infusion at the low rate, when started during phase II of the migrating myoelectric complex, induced the premature phase III after 10 +/- 2 min and caused about 20% reduction of cycle duration in the duodenum as compared to control experiments (P less than 0.05). Fast administration of hepatic bile elicited the premature phase III in 8 +/- 2 min, caused 20-30% reduction of the duodeno-jejunal cycle duration (P less than 0.05) in comparison with control group and induced in 26% phase III in the stomach. Cycles were shortened at the expense of markedly decreased duration of phase I; for example in the duodenum phase I was reduced from 30 +/- 3 (control experiments) to 11 +/- 2 min, P less than 0.001. Standard bile infusion exerted less pronounced changes, apart from increasing the propagation velocity of phase III in the first jejunal segment from 6 +/- 0.5 cm.min-1 in control group to 13 +/- 3 cm.min-1, P less than 0.05. In two experiments rapid bile administration evoked an inhibitory response. Results obtained suggest that the luminal bile stimulates the interdigestive electrical activity of the stomach and small bowel of the dog. This stimulatory effect may represent the feedback mechanism preventing the prolonged retention of continuously inflowing bile in a bowel section and, particularly, in the duodenum.

Action Potentials↗

PubMed1988

Effect of butorphanol, pentazocine, meperidine, or metoclopramide on intestinal motility in female ponies.

Effect of butorphanol, pentazocine, meperidine, and metoclopramide on jejunal and pelvic flexure myoelectric and mechanical activity in 4 female ponies was investigated. The agent to be tested or saline solution was administered IV at the start of a 6-hour recording trial. In the jejunum, duration between activity fronts of regular spiking activity, defined as the length of the migrating myoelectric complex (MMC), was measured. The average duration of the MMC during control trials was 150 +/- 46 minutes. The average duration of the MMC after meperidine, butorphanol, pentazocine, and metoclopramide administration was 295 +/- 70 minutes, 260 +/- 60 minutes, 275 +/- 60 minutes, and 163 +/- 64 minutes, respectively. Meperidine, butorphanol, or pentazocine significantly increased the MMC duration (P less than 0.05), and did not significantly alter the pelvic flexure activity. Seemingly, meperidine, butorphanol, and pentazocine inhibited cyclic myoelectric activity in the jejunum. Metoclopramide had no effect on jejunal or pelvic flexure motility.

Analgesics↗

PubMed1988

Graded effect of protein on regional myoelectric activity of the opossum sphincter of Oddi.

Although it is known that the sphincter of Oddi exhibits a myoelectric response to intraluminal nutrients, the effect of specific dietary components has not been well characterized. The aim of this study was to determine the effect of intragastric instillation of a protein meal on regional myoelectric activity of the opossum sphincter of Oddi. Seven adult opossums were chronically prepared with self-retaining bipolar electrodes secured to the proximal and distal parts of the sphincter. After a 2-week recovery period, and with the animals fasted and conscious, myoelectric activity was recorded for two cycles of the migrating myoelectric complex. The animals then received graded calories of protein through an orogastric tube and recordings were continued until return of the fasted cyclic activity. Doses of 60, 120, and 240 kcal of protein elicited increases in myoelectric spike activity of the proximal sphincter of 18.7%, 41.9%, and 66.6%, respectively. Similarly, the length of the fed state was prolonged by increasing caloric loads, with mean (plus or minus standard error of the mean) times of 266 +/- 25, 292 +/- 15, and 375 +/- 42 minutes for each dose. A similar relationship was noted in the distal part of the sphincter. Regression analysis between the proximal and distal parts of the sphincter during the fasted and fed states showed a strong and persistent correlation of gradient of spikeburst frequency. We conclude that myoelectric spike frequency of the opossum sphincter of Oddi exhibits a dose-related response to intragastric protein calories. Furthermore, the proximal and distal parts of the sphincter remain electrically coupled, with the proximal region pacing the distal region during the fasted state and after protein administration.

Ampulla of Vater↗

PubMed1987

Gastroduodenal motility in neonates: response to human milk compared with cow's milk formula.

It is known that breast milk empties more quickly from the stomach than does infant formula. We studied the difference in gastroduodenal motility between neonates fed with human milk and those fed with infant formula. Twenty-four five- to 36-day-old neonates were fed with mother's breast milk or with a cow's milk-based formula. Postprandial gastroduodenal contractions were recorded manometrically for three hours. Repetitive, high-amplitude nonmigrating contractions were the dominant wave form during the postprandial period. The number of episodes, duration, amplitude, and frequency of nonmigrating contractions were not different following the different feedings. The migrating myoelectric complex, which signals a return to the interdigestive (fasting) state, appeared in 75% of breast milk-fed infants but only 17% of formula-fed infants (P less than .05) within the three-hour recording period. Because contractions were similar following the two meals, but a fasting state recurred more rapidly in breast-fed infants, we conclude that factors other than phasic, nonpropagated antroduodenal contractions were responsible for the differences in gastric emptying between breast milk and formula.

Adult↗