Myoelectric Activity Of Small Intestine Research Articles

Prostaglandins and modulation of small bowel myoelectric activity.

We explored the effects of prostaglandins (PG) F2 alpha and E2 on the motor and myoelectric activity of the small intestine using closed intra-arterial injections in conscious chronically instrumented dogs. PGF2 alpha (0.125-5 micrograms) and PGE2 (1-10 micrograms) were injected via a T tube into a branch of the superior mesenteric artery perfusing a 15-cm segment of jejunum. Experiments were performed on four dogs in which the recording devices had been implanted above, below, and within the perfused segment. PGF2 alpha given during phase I of the migrating myoelectric complex cycle induced phasic contractions in the perfused segment of intestine in a dose-dependent manner. Atropine (50-100 micrograms), hexamethonium (15 mg), or TTX (10-15 micrograms) administered before the injection of PGF2 alpha failed to inhibit the effects of PGF2 alpha. In contrast pretreatment of the perfused segment with verapamil (2.5 mg) or PGE2 (1-5 micrograms) abolished the effects of PGF2 alpha. Moreover, PGE2 injected 5 min after the administration of PGF2 alpha inhibited the PGF2 alpha-induced contractions. Administration of PGE2 alone (3-10 micrograms) before the arrival of phase III activity in the perfused segment abolished phase III from this segment of intestine. Our studies indicate opposing effects of PGF2 alpha and PGE2 on small intestinal myoelectric and contractile activities. PGF2 alpha has a direct excitatory effect on the intestinal smooth muscle, which is calcium channel dependent but independent of intrinsic nerves. PGE2 has an inhibitory effect both on the spontaneous and PGF2 alpha-induced small intestinal myoelectric and contractile activity.

The migrating myoelectric complex of the small intestine.

Gastric and small intestinal myoelectric and motor activity is divided into two main patterns, fed and fasted. During fasting, the predominant pattern of activity is the migrating myoelectric complex (MMC), a cyclically occurring pattern of electric and mechanical activity that is initiated in the stomach and duodenum almost simultaneously and, from there, propagates the length of the small intestine. Cyclic motor activity also occurs in the lower esophageal sphincter, the gallbladder, and the sphincter of Oddi with a duration that is related to the MMC in the small intestine. Of the possible mechanisms for initiation of the MMC in the small intestine (extrinsic neural control, intrinsic neural control, and hormonal control), intrinsic neural control via a series of coupled is the most likely. The keep this sentence in! hormone motilin also plays a role in the initiation of MMCs. After a meal, in man the MMC is disrupted and replaced by irregular contractions. The physiologic role of the MMC is to clear the stomach and small intestine of residual food, secretions, and desquamated cells and propel them to the colon. Disruption of the MMC cycle is associated with bacterial overgrowth in some patients, an observation that supports the proposed cleansing function of the MMC cycle.

Studies of Small Intestinal Myoelectrical Activity and Intraluminal Pressure Changes in the Unrestrained Conscious Rat

Our aim was to develop and validate a methodology to permit chronic recordings of small intestinal intraluminal pressure changes in the conscious rat and thereby to study regional variations in motor activity. A low‐flow (0.014 cc/min) perfusion system permitted reliable intraluminal pressure recordings at four sites along the small intestine from unrestrained animals. Comparison of overall patterns of fasted and fed motor activity and the various parameters of the migrating motor complex (MMC) from these recordings with those obtained from another group of animals prepared with serosal electrodes provided similar results in the proximal small intestine (MMC frequency 3.4 ± 0.5 vs. 3.9 ± 0.3 cycles/h, phase II duration 3.8 ± 0.7 vs. 4.7 ± 0.4 min, and phase III duration 4.0 ± 0.2 vs. 3.5 ± 0.2 min for duodenal catheters vs. electrodes, all NS). However, the distal deal phase II was considerably shorter in catheter than electrode recordings (6.0 ± 0.8 vs. 15.7 ± 2.4 min, p < 0.0001). Both methodologies confirmed significant regional variations in small intestinal motor parameters: the incidence of interdigestive myoelectrical complex (IDMEC) cycles was lower and phase II of the IDMEC was considerably prolonged in the distal Hewn. In summary, a system to permit chronic recordings of small intestinal intraluminal pressure has been developed and validated by comparison to myoelectrical recordings. Motor specialization was evident in the rat distal ileum.

Motor and Absorptive Function of the Canine Intestine Following Serosal Patching: The Effects of a Lateral Enterotomy on Small Intestinal Myoelectrical Activity

We studied the effects of serosal patching of a 4 x 15-cm, full-thickness, jejunal defect on absorptive function and fasting and postprandial myoelectrical activity in 5 patched and 5 control animals over a 3-month period. While fat and D-xylose absorption were similar in both groups, serum albumin was significantly depressed (2.96 +/- 0.24 g/dL preop vs 2.29 +/- 0.23 g/dL postop, p less than .05) and stool moisture content was elevated following patching (54 +/- 4% vs 67 +/- 9%, p less than .05). Neither the generation of the various phases of the interdigestive myoelectrical complex (IDMEC), the development of postprandial myoelectrical activity, or colonic myoelectrical patterns were impaired in the patched animals. The normal gradients of slow wave frequency, phase III propagation velocity, and onset of the fed pattern were similar in control and patched animals. However, jejunal slow wave frequency (cpm, control vs patch: 18.6 +/- 0.6 vs 19.5 +/- 0.6, p less than .05) and IDMEC frequency (0.36 +/- 0.25 vs 0.56 +/- 0.32, p less than .05) were greater and the IDMEC period shorter (109.6 +/- 27.8 vs 88 +/- 35.7, p less than .05) in the patch animals. In vitro studies demonstrated similar absorptive function in intact mucosa and neomucosa. We conclude that the technique of serosal patching is associated with impaired absorption in vivo. While this may be related, in part, to the minor motility changes observed, other factors such as hormonal changes may also be important.

Small Intestinal Myoelectric Activity in Healthy Neonatal Piglets

We evaluated 17 healthy neonatal piglets to determine the effects of an increased hyperosmolal formula (HOF; 874 +/- 30 mOsmol/kg, n = 9) and commercial pig milk formula (CF; 482 +/- 35 mOsmol/kg, n = 8) on small intestinal myoelectric activity (SIMEA). Four bipolar electrodes were surgically implanted along the small intestine to evaluate myoelectrical parameters and patterns of SIMEA during fasting and postprandial periods. Durations of myoelectric phase activity and migrating motility complex periodicity were unaffected by both formulas. Differences in SIMEA were not significant when CF and HOF were compared. Following a single meal of increased HOF, piglets demonstrated a significant postprandial increase of phase 2 myoelectric activity in the duodenum through ileum (p less than 0.05) and time-dependent decrease of phase 3 activity in the duodenum (p less than 0.05) and jejunum through terminal ileum (p less than 0.01). Diminished phase 3 activity in the terminal ileum persisted throughout the 4-h postprandial period (p less than 0.01) and was related to fewer phase 3 episodes in this region (p less than 0.05). This pattern of myoelectric activity has been associated with decreased intestinal propulsion and clearing of intraluminal contents. We conclude that a single meal of HOF does not result in significant intestinal motor dysfunction in healthy neonatal piglets. It remains to be determined whether postprandial reductions of phase 3 myoelectric activity that follow a hyperosmolal meal serve as a precursor to neonatal necrotizing enterocolitis when additional risk factors exist.

Hyperosmolal Formula in Neonatal Piglets

SummaryIngestion of hyperosmolal formula (HOF) by neonatal piglets has been shown to cause significant time‐dependent reduction in phase 3 myoclectric activity, which persists in the terminal ileum. To determine whether a single hyperosmolal meal leads to elevated concentrations of gastrointestinal (GI) hormones that inhibit intestinal motility and/or promote bacterial proliferation and disruption of intestinal mucosa, we studied 20 healthy neonatal piglets following feeding with an increased HOF (872 ± 32 mOsmol/kg, n = 10) and commercial pig milk formula (481 ± 41 mOsmol/kg, n = 10). Gastrin, secretin, cholecystokinin, and motilin concentrations were determined by radioimmunoassay during fasting and postprandial periods (15, 30, 45, 120, 180, and 240 min). Gastrin concentrations were significantly increased at 15 and 30 min following a hyperosmolal meal (p < 0.01), but there were no statistical differences in GI hormone concentrations between groups. These transient elevations of gastrin concentrations are associated with significant postprandial reductions in phase 3 small intestinal myoelectric activity (SIMEA) that we have observed. Aerobic bacterial titers were not significantly different between proximal and distal small intestinal segments or between experimental groups, and anaerobic bacteria were seldom recovered. Thus, SIMEA was not sufficiently altered to produce significant bacterial proliferation. Small intestinal histology, assessed by light microscopy, showed normal proximal and distal small intestinal mucosa in 8 of 10 piglets from each group. Therefore, orogastric instillation of a single hyperosmolal feed does not result in intestinal mucosal damage. Further studies are warranted to determine the effects of hyperosmolal feeds when additional risk factors exist in the neonate.

Small Intestinal Myoelectric Activity in Healthy Neonatal Piglets

SummaryWe evaluated 17 healthy neonatal piglets to determine the effects of an increased hyperosmolal formula (HOF; 874 ± 30 mOsmol/kg, n = 9) and commercial pig milk formula (CF; 482 ± 35 mOsmol/kg, n = 8) on small intestinal myoelectric activity (SIMEA). Four bipolar electrodes were surgically implanted along the small intestine to evaluate myoelectrical parameters and patterns of SIMEA during fasting and postprandial periods. Durations of myoelectric phase activity and migrating motility complex periodicity were unaffected by both formulas. Differences in SIMEA were not significant when CF and HOF were compared. Following a single meal of increased HOF, piglets demonstrated a significant postprandial increase of phase 2 myoelectric activity in the duodenum through ileum (p < 0.05) and time‐dependent decrease of phase 3 activity in the duodenum (p < 0.05) and jejunum through terminal ileum (p < 0.01). Diminished phase 3 activity in the terminal ileum persisted throughout the 4‐h postprandial period (p < 0.01) and was related to fewer phase 3 episodes in this region (p < 0.05). This pattern of myoelectric activity has been associated with decreased intestinal propulsion and clearing of in‐traluminal contents. We conclude that a single meal of HOF does not result in significant intestinal motor dysfunction in healthy neonatal piglets. It remains to be determined whether postprandial reductions of phase 3 my oelectric activity that follow a hyperosmolal meal serve as a precursor to neonatal necrotizing enterocolitis when additional risk factors exist.

Hyperosmolal Formula in Neonatal Piglets

Ingestion of hyperosmolal formula (HOF) by neonatal piglets has been shown to cause significant time-dependent reduction in phase 3 myoelectric activity, which persists in the terminal ileum. To determine whether a single hyperosmolal meal leads to elevated concentrations of gastrointestinal (GI) hormones that inhibit intestinal motility and/or promote bacterial proliferation and disruption of intestinal mucosa, we studied 20 healthy neonatal piglets following feeding with an increased HOF (872 +/- 32 mOsmol/kg, n = 10) and commercial pig milk formula (481 +/- 41 mOsmol/kg, n = 10). Gastrin, secretin, cholecystokinin, and motilin concentrations were determined by radioimmunoassay during fasting and postprandial periods (15, 30, 45, 120, 180, and 240 min). Gastrin concentrations were significantly increased at 15 and 30 min following a hyperosmolal meal (p less than 0.01), but there were no statistical differences in GI hormone concentrations between groups. These transient elevations of gastrin concentrations are associated with significant postprandial reductions in phase 3 small intestinal myoelectric activity (SIMEA) that we have observed. Aerobic bacterial titers were not significantly different between proximal and distal small intestinal segments or between experimental groups, and anaerobic bacteria were seldom recovered. Thus, SIMEA was not sufficiently altered to produce significant bacterial proliferation. Small intestinal histology, assessed by light microscopy, showed normal proximal and distal small intestinal mucosa in 8 of 10 piglets from each group. Therefore, orogastric instillation of a single hyperosmolal feed does not result in intestinal mucosal damage. Further studies are warranted to determine the effects of hyperosmolal feeds when additional risk factors exist in the neonate.

Myoelectric activity of small intestine after chemical ablation of myenteric neurons

Ablation of the myenteric plexus was performed by serosal application of 0.062% benzalkonium chloride (BAC) in the duodenum, proximal and distal jejunum, and ileum. The thickness of muscle layers and the number and sizes of ganglia and neurons of the myenteric plexus were evaluated before and 21-28 days after treatment. Electrodes were implanted on the treated segments and on segments orad and aborad to the treated segment. The electromyogram of each segment was recorded daily for periods of 2-3 h. The number of myenteric neurons in the BAC-treated segment was decreased significantly by 85 to 98% relative to segments removed before BAC application. Significantly, thickening of longitudinal plus circular muscle layers amounted to 113% in the duodenum and 261% in the ileum in the treated segment. No changes were observed in electrical slow-wave frequency in treated segments. Spike activity (percentage of slow waves with spikes) increased in the BAC-treated segment by 92% compared with recording sites orad and aborad to the treated segment and to the small intestine in untreated control animals. We interpreted the increase in spike activity in treated segments to reflect the loss of inhibitory neuronal influence. The hyperplasia and hypertrophy of the longitudinal and circular muscle coat could have resulted from a direct influence of the altered innervation or from work-induced hypertrophy in the treated segment secondary to uncoordinated hyperactivity of the disinhibited musculature.

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)

Suppression of small intestinal motility and morphine withdrawal diarrhoea by clonidine: peripheral site of action.

The effects of systemic administration of morphine (4.0 mg kg-1) and clonidine (2.5-10.0 micrograms kg-1), as well as the peripherally active alpha 2-adrenoceptor agonist oxymetazoline (2.8-11.2 micrograms kg-1), were studied on the migrating myo-electric complexes (MMCs) of the small intestine in conscious, naive rats. Furthermore, the effects of naloxone (1.0 mg kg-1) and the peripherally acting opioid antagonist, methylbromide naloxone (1.0-2.0 mg kg-1) were studied on the MMCs in morphine-dependent animals. Similar doses of clonidine or oxymetazoline inhibited the MMCs of the small intestine, which suggests a peripheral site of action of clonidine. Since naloxone (1.0 mg kg-1) did not antagonize the effect of clonidine, and yohimbine (1.0 mg kg-1) failed to antagonize the effect of morphine on the MMC, the inhibitory effects on intestinal motility of clonidine and morphine are mediated through different receptors. Morphine-dependent rats showed a prolonged interval between activity fronts and decreased propagation velocity of the activity fronts. Both naloxone (1.0 mg kg-1) and methylbromide naloxone (1.0-2.0 mg kg-1) induced intense spiking activity and profuse diarrhoea. Clonidine (5.0-10.0 micrograms kg-1) as well as oxymetazoline (5.6-11.2 micrograms kg-1) given prior to naloxone prevented the intense spiking as well as the concomitant diarrhoea. We conclude that the potent inhibition of small intestinal myoelectric activity by alpha 2-adrenoceptor agonists is mainly executed via peripheral mechanisms. This effect may contribute to their beneficial action in morphine withdrawal diarrhoea, and partly underlie a general antidiarrhoeal action.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of intraluminal nutrients on intestinal myoelectric activity in rabbits.

In the unanesthetized rabbit, intraluminal infusions of D- and L-methionine, L-tryptophan, D-glucose, D-xylose, and lactulose had a biphasic effect on small intestinal myoelectric activity. A phase of enhanced activity was followed by a phase of inhibition. The excitatory phase was mimicked by saline solutions equiosmolar to the test solutions. The subsequent inhibition was does dependent and significantly (P less than 0.01) longer for the passively absorbed D-methionine than for the L-stereoisomer. The inhibitory action of 10 mM D-glucose, 10 mM L-methionine, and 5 mM L-tryptophan was blocked by propranolol on the jejunum and by phenoxybenzamine on the ileum. We conclude that the initial excitatory phase induced by luminal amino acids and sugars may be dependent on an action on osmoreceptors, whereas the subsequent inhibitory phase may involve the sympathetic noradrenergic system.

Valosin Stimulates Gastric and Exocrine Pancreatic Secretion and Inhibits Fasting Small Intestinal Myoelectric Activity in the Dog

Valosin, a novel 25-amino acid gastrointestinal peptide with N-terminal valine and C-terminal tyrosine, has recently been isolated from porcine upper gut extracts. Its physiologic role is unknown and it does not belong to one of the structurally related gut peptide families. Assuming that valosin may influence gastrointestinal functions, we investigated the effect of high-performance liquid chromatography-pure valosin on gastric and exocrine pancreatic secretion and on the intestinal myoelectric activity in conscious dogs. Intravenous injection of valosin (0.125-1 microgram/kg) dose-dependently increased gastric acid secretion 80-fold over basal, corresponding to 18% of the maximal pentagastrin-induced effect. Pepsin output increased 10-fold over basal (30% of the pentagastrin-stimulated secretion). Half-maximal stimulation by pentagastrin could be further increased dose-dependently by simultaneous administration of valosin. Pancreatic bicarbonate secretion was stimulated 11-fold over basal at 1.0 microgram/kg, reaching about 6% of the secretin-induced maximal output, whereas protein secretion increased 12-fold over basal, corresponding to about 55% of the cholecystokinin-induced maximal output. In fasted dogs, spontaneously occurring migrating myoelectric complexes were substantially delayed during infusion of valosin at a dose of 0.2 microgram/kg. These experiments indicate that valosin may represent a novel member of the regulatory gastrointestinal peptides.

Effect of central sympathectomy on gastric and small intestinal myoelectric activity and plasma motilin concentrations in the dog

Using a canine model, we studied fed and fasting gastric and small intestinal myoelectric activity and plasma motilin concentrations before and after transection of the spinal cord between the second and third thoracic segments. In sham-operated dogs, migrating complexes returned to normal by the second day after operation. Immediately after spinal cord transection, migrating complexes cycled in jejunum and ileum but not in the stomach and duodenum. After 11 and 15 days, migrating complexes returned to the duodenum and stomach, respectively. Plasma motilin concentrations did not cycle in animals without duodenal migrating complexes but returned to a normal cyclical pattern when duodenal migrating complexes returned. Feeding interrupted migrating complexes after cord transection and sham operation. The data observed in animals after 15 days suggest that myoelectric activity in fasted dogs and conversion of the fasted to the fed state of myoelectric activity are not under the control of supraspinal, sympathetic pathways.

Gastric influences on canine small intestinal myoelectric activity.

The aim was to determine whether the canine stomach modulates interdigestive and digestive small intestinal myoelectric activity. In four conscious dogs with electrodes implanted chronically on the duodenum and jejunum, enteric myoelectric activity was recorded during fasting and after feeding a 200-g liver meal. The dogs then underwent total gastrectomy and esophagoduodenostomy, after which they were restudied. Gastrectomy did not alter the pattern of the enteric interdigestive myoelectric complexes; the occurrence, period, duration of phase III, and consistency of distal propagation of enteric IMCs remained unchanged. Gastrectomy also preserved both the postcibal inhibition of the enteric IMCs and the postcibal induction of the fed myoelectric pattern in the small bowel. However, the onset of the fed pattern occurred more promptly after gastrectomy than before gastrectomy. We concluded that the pattern of canine duodenal and jejunal interdigestive myoelectric activity was largely independent of the stomach. The more rapid onset of the fed pattern with feeding postgastrectomy may relate to more rapid entry of chyme into the small intestine.

Colonic migrating and nonmigrating motor complexes in dogs.

We report here the characteristics of a cyclic motor activity in the colon of conscious dogs and its relationship to small intestinal migrating motor complexes (MMCs). The colonic motor activity was recorded by four equispaced strain gauges and small intestinal myoelectric activity by four equispaced bipolar electrodes. The colonic motor activity was characterized by rhythmic bursts of contractions. The mean durations of bursts of contractions varied from 7.0 to 11.5 min at the four colonic recording sites. Those bursts of contractions which migrated over at least three recording sites were called colonic migrating motor complexes (CMMCs). All other patterns of bursts of contractions were called colonic nonmigrating motor complexes (CNMCs). A total of 160 CMMCs were recorded during a total recording period of 132 h; 151 CMMCs migrated caudad and 9 orad. The mean period of caudad migrating CMMCs was 53.3 +/- 5.4 (SE) min, and their mean migration time was 11.3 +/- 1.2 (SE) min. The onset of CMMCs was not temporally related to the onset of small intestinal migrating myoelectric complexes in the duodenum or their arrival in the terminal ileum. CMMCs did not have phases I to IV like those of small intestinal MMCs, but two consecutive CMMCs were separated by a quiescent state or by one or more randomly occurring bursts of contractions (CNMCs).

Pregnancy-Related Changes in Small Intestinal Myoelectric Activity in the Rat

To determine if changes in intestinal motility occur during pregnancy, we studied small intestinal myoelectric activity, using monopolar electrodes, in fasted pregnant rats from day 12 to day 18 of the 22-day gestation period. We also studied fasting myoelectric activity in postpartum, nonpregnant, and castrate females. In all rats, the interdigestive myoelectric complex was invariably present with recurring activity fronts appearing at the proximal electrode and moving slowly abroad. Intervals between fronts were similar in all four groups, ranging from 12.61 min to 14.58 min. In pregnant rats, however, there was loss of the periodicity characteristic of activity fronts in the other groups; intervals up to 43 min in length were occasionally noted. Unorganized, randomly occurring spike potentials characterized these intervals. The average coefficient of variation of interval length was significantly (p less than 0.05) greater in pregnant rats (0.401) than in castrate (0.197) and nonpregnant rats (0.248). These studies confirm the presence in rats of pregnancy-related changes in small intestinal myoelectric activity.

Alteration of myoelectric activity of small intestine by invasive Escherichia coli.

Invasive strains of Escherichia coli (4608-58 and TD 213 CL) altered myoelectric activity of the small intestine in New Zealand White rabbits. The altered myoelectric activity had two distinct complex patterns. The first was defined as repetitive bursts of action potentials (RBAPs) that occurred predominantly in infected ligated ileal loops. The RBAP activity is characterized by action potential discharge activity greater than 1.5 s in duration and occurring on three or more successive slow waves on the same electrode recording site. These bursts of action potentials often migrated to adjacent electrode sites. The second complex pattern, defined as the migrating action potential complex (MAPC), occurred predominantly in the uninfected small intestine orad to the ligated ileal loop. The MAPC consists of action potential discharge activity of 2.5 s or longer that propagates aborally over at least two consecutive electrode sites. These studies demonstrated an altered myoelectric pattern, the RBAP, characteristic of invasion within the infected ligated loop. The MAPC, characteristic of noninvasion, was noted in the uninfected proximal small intestine.

Effect of toxigenic Escherichia coli on myoelectric activity of small intestine.

When exposed to cholera toxin (CT), distal ileal loops of the rabbit small intestine showed an alteration in myoelectric activity. This alteration was defined as the migrating action potential complex (MAPC). The purpose of this study was to determine, using myoelectric recording techniques, the effects of live toxigenic Escherichia coli (TEC) on motility. Live TEC, live nontoxigenic E. coli (NTEC), and culture filtrates of these organisms were studied. Live TEC and its filtrate induced MAPC activity similar to that of CT. Live TEC induced a mean of 3.8 MAPCs/h, significantly greater than induced by live NTEC. TEC filtrate induced a mean of 14.2 MAPCs/h, significantly greater than NTEC filtrate. Heating the TEC filtrate to 100 degrees C before use resulted in a significant decrease of MAPC activity. This experiment demonstrated that live TEC and its culture filtrate altered ileal myoelectric activity. The effect may have been mediated by a heat-labile enterotoxin. This study suggests that alterations in small intestinal motility may be important in the pathogenesis of TEC diarrhea.

A new cannula for the study of pancreatic function.

A new cannula for the study of pancreatic function.