Small Bowel Motor Activity Research Articles

Su1911 Neuropeptide S: Effects on Motility, Contractility and Inflammation in the Rat and Human Gastrointestinal Tract

Background: Neuropeptide S (NPS) is expressed by gastrointestinal (GI) enteroendocrine cells and macrophages in rat and man. Polymorphisms of the NPS receptor are linked to increased risk of inflammatory bowel disease as well as motor and sensory disturbances of the gut, suggesting a role for NPS in GI disorders. Further knowledge of NPS effects on motility and inflammation is needed. Methods: Studies of motility were carried out in rats with electrodes implanted in the small bowel. NPS was infused IV for 60 min and effects on myoelectrical activity were recorded. Motility effects of NPS were further studied as luminal pressure changes in anaesthetized rats where the proximal small intestine with intact blood supply was perfused with saline for motility recordings. Tissue samples were obtained from rats for evaluation of gene expression and protein elaboration of inflammatory biomarkers. Muscle strips of the human stomach, small intestine and colon were used for pharmacological analysis in organ baths of motility responses to NPS. Localization of the NPS receptor was done with fluorescent-protein tagging using Cy3-NPS. Plasma levels of NPS were measured using ELISA in 5 healthy and 14 IBD patients before and after meal. Results: In conscious rats, NPS 1 nmol kg-1min-1 increased irregular spiking, 4 nmol kg-1min-1 reduced spiking and increased the MMC cycle length (P=0.005). In anesthetized rats, NPS 0.01-1 nmol kg-1min-1 dose-dependently reduced small bowel motility (P<0.001). In rats, NPS also increased the mRNA expression of iNOS, and CXCL1 and IL-1β at the protein level. In human, fluorescent protein-tagging showed the NPS receptor primarily to be present in enolase-positive nerve fibers, but some scattered also in muscle tissue. In organ baths, NPS 1-100 nM caused TTX-dependent relaxations of the smooth muscle. We found no detectable levels of NPS in plasma of neither healthy subjects nor IBD patients. Conclusion: NPS has a smooth muscle-relaxing effect in the GI tract and dampens myoelectrical and contractile motor activity of the small bowel. This is achieved primarily through an inhibition of nerve-mediated relaxation of smooth muscle cells. Circulating NPS levels in humans are undetectable in healthy subjects and in active IBD. This implies that NPS exerts its inhibitory function by a paracrine or neurocrine mechanism in the gut. NPS seems also capable of intervening with inflammation by increasing gut cytokines and iNOS expression.

Outcome of small-bowel motor impairment in systemic sclerosis--a prospective manometric 5-yr follow-up

To assess the 5-yr course of small-bowel motor disorders, using manometry in patients with systemic sclerosis (SSc), and to investigate for an association between small-bowel motor dysfunction outcome and other clinical manifestations of SSc. Fasting and post-prandial motor activity of the small-bowel was systematically assessed in eight consecutive patients with SSc, using 24 h manometry: initially and at 5-yr follow-up. At 5-yr follow-up, the eight SSc patients (100%) exhibited deterioration of small-bowel motor activity on manometry as follows: (1) more severe abnormalities of migrating motor complex phase III during the fasting period; (2) decreased median duodenal and duodeno-jejunal index during the post-prandial period; and (3) more frequent alterations of small-bowel motor activity in response to octreotide infusion. Furthermore, an association could be found between the deterioration of small-bowel motor function and pitting scars' onset. Our study underscores the rapid deterioration of small-bowel motor impairment in SSc patients (100%). It also highlights the usefulness of small-bowel manometry in symptomatic SSc patients in objectively defining both the characteristics and degree of motor impairment, which may influence the choice of medical treatment in patients, particularly octreotide therapy.

¿Existe en la constipación idiopática severa un trastorno difuso de la motilidad intestinal?

Studies in patients with chronic severe constipation, suggest the presence of a diffuse motor disorder of the gastrointestinal tract. To investigate small bowel motor activity in a group of patients with severe constipation. Forty three patients (age range 13 to 70 years, 40 women) with severe constipation referred to our motility laboratory, where studied. Ten had a previous colectomy. Radiological examinations showed a megacolon in 30 and dilatation of small intestinal loops in nine; the remaining X rays studies were normal. Small intestinal motility was studied using perfused catheters and external transducers. Ten patients had normal motor recordings. Eight patients showed a neuropathic disorder characterized by a continuous irregular pattern of contractions of normal amplitude, with absence of phase III of the migrating motor complex (MMC). Sixteen presented a normal MMC associated to a decreased amplitude of contractions (Miopatic disorder). Nine showed both types of motor disorders (Mixed pattern). Normal radiological findings were more commonly associated to normal manometric recordings. By contrast, an altered motor activity, mainly of myopathic and mixed type motor disorder, was observed in all patients with dilated small intestinal and colonic loops. The presence of small intestinal motor disorders was a frequent finding in this selected group of patients with chronic constipation.

Small Bowel Motor Activity in Response to Physiological Meals of Different Chemical Composition in Man

Meals disrupt the interdigestive pattern of small bowel motor activity and convert it into the more irregular postprandial pattern. Previous animal studies suggest that the duration of and contractile activity within the postprandial period depend on the chemical composition of a meal. It is not clear whether this is also true for man. In 8 healthy volunteers I investigated how physiological and isocaloric meals of different chemical composition affect small bowel motor activity. Volunteers underwent two separate, ambulatory 24-hour small bowel manometry studies. Volunteers had a total of four meals on the two study days. They ingested two identical fish meals rich in protein, a pasta meal rich in carbohydrates, and a meat meal rich in fat. Records were analyzed visually for the reappearance of phase III of the migrating motor complex, and a validated computer program calculated the incidence of contractions during the postprandial period, as well as the amplitude and propagation of contractions. The durations of the postprandial periods were similar after the two protein meals (238 +/- 35 and 227 +/- 25 min), the carbohydrate (220 +/- 23 min) and the fat meal (242 +/- 43 min). The incidence of contractions was not significantly different after the protein meals (1.6 +/- 0.3 and 1.0 +/- 0.2 contractions per min), the carbohydrate meal (1.0 +/- 0.2 contractions per min) and the fat meal (1.5 +/- 0.2 contractions per min). The amplitude of contractions was similar after the protein meals (14 +/- 0.1 and 13 +/- 0.1 mmHg), the carbohydrate meal (14 +/- 0.1 mmHg) and the fat meal (14 +/- 0.1 mmHg). Propagation of contractions was similar after the protein meals (13 +/- 3 and 18 +/- 3 %), after the carbohydrate meal (15 +/- 2 %) and after the fat meal (13 +/- 2 %). Contractile activity within consecutive 30-min periods of the postprandial period was also not different between the meals. I conclude that physiological, isocaloric meals of different chemical composition elicit a similar postprandial motor response in the human small bowel.

Small bowel motility

The publications relevant to small bowel motility have been concentrated during the past year in several main areas: further characterization of normal patterns of small bowel motor activity and transit, physiologic control mechanisms, visceral hypersensitivity, inflammation and motility, disease processes and dysmotility, and novel pharmacologic approaches to altered sensorimotor activity.

Small bowel motility in primary biliary cirrhosis.

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

Small bowel motility in primary biliary cirrhosis

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

Human small bowel motor activity in response to liquid meals of different caloric value and different chemical composition.

Previous animal studies have shown that the nature and duration of postprandial motility in the small bowel depend both on the caloric load and the chemical composition of a meal. It is not clear whether this is also true for the human small bowel. Therefore we investigated the motor activity of the human small bowel in response to nutrient liquids of different caloric value and different chemical composition. Ten human volunteers underwent three separate, 24-hr ambulatory manometry studies. They drank water, a pure glucose solution, and Intralipid 10% in volumes of both 300 and 600 ml. The caloric value of the nutrient liquids was 330 and 660 kcal, respectively. Records were analyzed visually for the reappearance of phase III of the MMC after ingestion of a test liquid, and a validated computer program calculated the incidence and amplitude of contractions during the postprandial period. Neither duration of the postprandial interval nor the mean incidence or mean amplitude of contractions were different between the fat and the carbohydrate solutions, but phase III reappeared significantly later after ingestion of the nutrient liquids than after water (P = 0.0002). Duration of the postprandial interval also depended on the volume or the caloric load of a liquid meal (P = 0.0012). Mean incidence of contractions tended to be higher after ingestion of nutrient liquids than after water (P = 0.059). We conclude that in ambulant subjects, small bowel motor activity in response to chemically diverse liquid meals is remarkably uniform. This is true for the duration of the postprandial motor activity, as well as the incidence and amplitude of contractions during that period. The caloric value of a liquid meal, however, regulates the duration of the postprandial interval in the human small bowel.

Small bowel dysmotility in patients with postcholecystectomy sphincter of Oddi dysfunction.

Postcholecystectomy patients (N = 27) with severe recurrent biliary-like pain who had no evidence of organic disease were subdivided into those with and those without objective evidence of sphincter of Oddi dysfunction (SOD) based on two separate criteria: (1) clinical criteria-elevated liver function tests and/or amylase with pain, and/or a dilated bile duct, and/or delayed drainage at ERCP (N = 14, SOD classes I and II); and (2) abnormal biliary manometry (N = 19). Prolonged (24-48 hr) ambulant recording of duodenojejunal motor activity was performed in all patients and interdigestive small bowel motor activity compared between patient subgroups and a healthy control group. Phase II motor abnormality was more frequent in patients with, compared to those without, objective clinical criteria of SOD (7/14 vs 0/13, P = 0.003). Phase III abnormality also tended to be more frequent in these patients (7/14 vs 2/13, P = 0.06). In addition, both phase III (P = 0.03) and phase II (P = 0.03) motility index (MI) was higher in patients with sphincter dyskinesia compared to controls; phase II MI was also higher in patients with sphincter stenosis (P = 0.005). Disturbances of small bowel interdigestive motor activity are more prevalent in postcholecystectomy patients with, compared to those without, objective evidence of SOD, and especially in patients with SO dyskinesia. Postcholecystectomy SOD in some patients may thus represent a component of a more generalized intestinal motor disorder.

Effect of some abdominal surgical operations on small bowel motility in humans: our experience.

Until recently, it was only possible to make inferences about small bowel motility from experimental animal models, but manometric techniques now allow prolonged recordings of small bowel motor activity in humans. We have studied the effect of abdominal surgery on motor behavior of the small intestine and here report our observations after various surgical procedures (total gastrectomy, Billroth I and II gastrectomy, ileoanal anastomosis). We discuss the data together with the experiences of others.

Small bowel (SB) motor activity in primary biliary cirrhosis (PBC): [formula omitted], Defilippi C, Brahn J, Antezana C, Gonzalez-K A, Defilippi Cl, Pimentel C, Valenzuela JE. GI Unit, Univ of Chile Hospital, Santiago, Chile

Small bowel (SB) motor activity in primary biliary cirrhosis (PBC): [formula omitted], Defilippi C, Brahn J, Antezana C, Gonzalez-K A, Defilippi Cl, Pimentel C, Valenzuela JE. GI Unit, Univ of Chile Hospital, Santiago, Chile

Small bowel motility following major intra-abdominal surgery: The effects of opiates and rectal cisapride

Background/Aims: Human small bowel motility is altered after laparotomy. Opiate analgesia is a possible cause of these alterations, and cisapride is a potential therapy. Methods: Continuous proximal small bowel manometry was performed for up to 92 hours in 23 patients after major intra-abdominal surgery. They were treated with rectal cisapride (30 mg three times daily) or placebo until the clinical resolution of ileus. Small bowel manometry was performed for 30 hours in 5 volunteers receiving 1 mg/kg meperidine over 3 hours. Results: Phase III activity was present within 3 hours of the end of surgery in all patients. Initially, the migrating motor complex (MMC) period was markedly reduced (mean, 22 minutes) but gradually increased. Phase II activity was absent until a median of 40 hours had elapsed. Phase III contractile amplitude was markedly attenuated in the jejunum, in contrast to that in the duodenum, presumably as a result of dilatation and/or altered tone, increasing to normal by 72 hours. In the volunteer group, although the MMC period was reduced by meperidine, it remained significantly greater than that of the placebo patient group for approximately 48 hours and phase II was reduced but not eliminated. Cisapride induced some changes in motor activity but did not accelerate the recovery of normal motility. Clinical outcome, assessed by the return of bowel sounds and passage of flatus, was accelerated by cisapride, but the trend was not significant (P = 0.11). Conclusions: This is the first published study using prolonged manometry to show the gradual evolution of small bowel motor activity after major intra-abdominal surgery. The findings suggest that surgery decreases the MMC period to the equivalent of the absolute refractory period, thereby eliminating phase II, which returns as the MMC period lengthens. Cisapride, at the dosage given, confers only modest benefit.

Muscarinic cholinergic receptor density following small intestinal transplantation in rats.

After small intestinal transplantation, intestinal isografts can organize migrating myoelectric complexes, and we have shown that migrating myoelectric complex frequency in the fasted state was reduced compared with controls after transplantation of the distal 50% of small intestine. We hypothesized that changes in motor activity after transplantation were related to alteration of cholinergic nerve activity or receptor density. With use of standard microsurgical techniques, the distal 50% of small intestine was orthotopically transplanted in a Lewis-to-Lewis donor-recipient combination. Resection controls were prepared by resecting the proximal 50% of small intestine, and sham controls were prepared by performing a sham laparotomy. Two months after surgery, small intestine was harvested. Choline acetyltransferase activity among the three groups was similar, suggesting that intrinsic cholinergic nerves remained intact. There was a strong trend toward decreased acetylcholinesterase activity [analysis of variance (ANOVA), P = 0.16] after transplantation, consistent with loss of extrinsic vagal nerve fibers. There were no differences in histochemical distribution of acetylcholinesterase among these groups. Muscarinic receptor density, as determined by binding to [N-methyl-3H]scopolamine, was decreased after transplantation (ANOVA, P = 0.02). There was a trend toward decreased receptor density in animals with resected small intestine. Surgical interruption of intrinsic nerve pathways rather than ischemia or extrinsic denervation might be the mechanism for diminished receptor density after transplantation, and reduced small bowel motor activity may be related to decreased density of muscarinic cholinergic receptors.

Divergent effect of saline and glucose solutions on myoelectric and motor activity of canine small bowel

AbstractPrevious work has shown that stimulation of osmotic receptors in the duodenal mucosa is followed by an increase in small intestinal motility. This effect was consistently observed with saline solutions, while stimulation or inhibition is observed when glucose is the solute. To gain further insight into the mechanisms of these apparent contradictory effects, we have perfused the intestine with saline and glucose solutions while simultaneously recording small bowel electrical and motor activity. Also to elucidate the influence of the spontaneous fasting activity, infusions were done on two different phases of the migrating motor complex infusion of 10 ml of both NaCl and glucose (1250 and 2500 mOsm/kg) in Phase I of the migrating motor complex, elicited the appearance of spike potentials and contractions. When infused during Phase II, NaCl caused an increase in the frequency of the irregular motor activity characteristics of this phase, due to a greater coupling of electrical and motor events. Also a greater amplitude of contractions was seen. In contrast, glucose infusion in Phase II was associated with a decrease of both electrical events and contractions. We conclude that the effect of hyperosmolar solutions is influenced by the solute and the phase of the migrating motor complex in which they are infused.

Short report: Effect of two prokinetic drugs on the electrical and motor activity of the small bowel in dogs

The effects of trimebutine and domperidone, on the electrical and motor activity of the upper small bowel in dogs, were studied simultaneously by means of a suction electrode and a manometric catheter. Trimebutine, given during phases I and II of the migratory motor complex, was followed by a period of regular spike potentials and contractions; the increased motor activity was significantly greater when the drug was given during phase II. Domperidone, when injected in phase I, was followed by an irregular pattern of spike potentials and contractions of low amplitude. By contrast, activity was not augmented when the drug was given during phase II. We conclude that the effects of drugs, such as trimebutine and domperidone, on the canine small bowel are influenced by the phase of the migratory motor complex.

Effects of intraduodenal and intravenous fat infusion on small bowel motility in humans. A comparative study of medium- and long-chain triglycerides

Objective: To test the effects of medium-chain triglycerides (MCT) and long-chain triglycerides (LCT), given intraduodenally or intravenously to healthy volunteers, on small bowel motility. Design: Two groups comprized of eight volunteers were studied. The 5-h fat infusion always began 30 min after a phase III. In study 1, volunteers received at random either 50 g LCT or MCT intraduodenally. In study 2, they received 500 ml of an emulsion of either LCT only or 50% LCT/50% MCT intravenously. Manometric recording continued from the beginning of fat delivery until the recurrence of a phase III after fat administration ceased. Results: In study 1, LCTs reduced phases III and I, while intraduodenal MCTs did not effect the fasting motor pattern of the small bowel. In study 2, phase III was recorded in all volunteers with both intravenous infusions. The percentage of time in phase III was greater with MCT than with the LCT infusion but the percentage of time in phases I and II remained the same with both types of intravenous fat. Conclusions: The effects of lipids on small bowel motor activity in humans depends on two parameters: the type of lipid and the route of administration.

Adrenergic blockade does not restore the canine gastric migrating motor complex during vagal blockade

Bilateral cervical cooling blockade of the vagi abolishes the gastric migrating motility complex (MMC), except for the pylorus. The present study investigated if this finding is caused by adrenergic inhibition of the stomach via sympathetic nerves entering the vagi below the level of the blockade. Stomach and upper small bowel motor activity was monitored in five chronic dogs whose vagosympathetic nerve trunks were previously isolated in bilateral, cervical skin loops to permit blockade by cooling. Adrenergic blockade was performed by an initial bolus injection of phentolamine (0.3 mg/kg) and propranolol (0.3 mg/kg) followed by a continuous intravenous infusion of the combined drugs at a rate of 1.5 mg · kg−1 · h−1 for phentolamine and 0.3 mg · kg−1 · h−1 for propranolol. Bilateral cervical vagal blockade abolished the gastric MMC, with persistence of phase III of the MMC in the upper small bowel. During combined vagal and adrenergic blockade, gastric contractions were absent in 4 of the 22 duodenal complexes observed. In the other duodenal complexes, intermittent gastric contractions were associated with all phases of the intestinal MMC, including phase I. At times, this contractile activity was accentuated during phase III but never reached the intensity of activity or showed the typical coordination features of the gastric MMC seen with the vagi intact. Therefore, unopposed adrenergic inhibition of the stomach does not explain the absence of the gastric MMC during vagal cooling blockade. Under normal circumstances, the vagus nerve is the most important pathway for central control of the appearance of the gastric MMC.

Erythromycin stimulates ileal motility by activation of dihydropyridine-sensitive calcium channels

Erythromycin, a macrolide antibiotic, is a potent stimulant of small bowel motor activity (MA) which may motility either via the peptide motilin receptor or neural mechanisms. We hypothesized that erythromycin stimulates directly stimulates smooth muscle cells by a calcium-mediated event. Thus, we evaluated the effect of neuronal blockade with tetrodotoxin, muscarinic blockade with atropine, and opiate blockade with naloxone on erythromycin-stimulated MA in isolated perfused segments of rabbit terminal ileum. We also tested the effect of nonspecific calcium channel blockade (verapamil and cadmiun) and specific blockade (dihydroxypyridine and nichol) on erythromycin-stimulated MA. MA was measured with a multichannel continuous perfusion manometry catheter. Erythromycin caused a concentration-dependent increase in MA (ED 100 5 × 10 −4 M). Tetrodotoxin, atropine, and naloxone did not effect erythromycin-stimulated MA ( P > 0.05). Both verapamil (10 −7 M) and cadmium (10 −2-10 −4 M) inhibited erythromycin-stimulated MA. Selective blockade of “1” type calcium channels using dihydropyridine (10 −6 M) and “t” channels with nickel (10 −2-10 −4 M) both reversed erythromycin-stimulated MA. Since the isolated segments of terminal ileum were free of exogenous humoral and neural effects, these studies indicated that erythromycin directly stimulated MA in the terminal ileum. Furthermore, since tetrodotoxin, atropine, and naloxone did not inhibit this increase in MA, erythromycin acted by a mechanism which was independent of the intrinsic nervous and opiate systems. In conclusion, these data are consistent with the model that erythromycin stimulates ileal motility by a mechanism involving activation of dihydroxypyridine and nickel-sensitive calcium channels.

Antral control of gallbladder cyclic motor activity in the fasting state

The hypothesis that gastric antrum controls the phasic contractions of gallbladder cyclic motor activity in the fasting state was tested. Gallbladder, gastric, and small bowel motor and myoelectric activity was recorded by strain gauge transducers and bipolar electrodes. Gallbladder pressure was measured manometrically by a surgically implanted intraluminal catheter. After control recordings for 4 to 6 weeks, antrectomy and gastroduodenostomy were performed. Six weeks later, bilateral truncal vagotomy was performed in each dog. Recordings were made after each surgical procedure. In the control state, the gallbladder exhibited cyclic motor activity consisting of phasic contractions at a frequency of 0.75 ± 0.02/min superimposed on an increase in baseline pressure. Antrectomy and gastroduodenostomy completely abolished the phasic contractions of gallbladder cyclic motor activity and significantly decreased the incidence of the cyclic increase in baseline pressure. Subsequent vagotomy had no additional effect on gallbladder cyclic motor activity. In intact dogs, the gallbladder filled from 0% to 80% and emptied from 80% to 100% of the duodenal migrating motor complex cycle, which was considered to begin at the start of phase I activity. Antrectomy significantly altered this pattern; after antrectomy, the gallbladder filled from 0% to 10% and from 90% to 100% and emptied during the remainder of the duodenal migrating motor complex cycle. Subsequent vagotomy had no additional effect on periodic gallbladder filling and emptying. It is concluded that major changes occur in gallbladder cyclic motor activity and its periodic filling and emptying pattern in the fasting state after antrectomy and vagotomy. It is hypothesized that in the absence of cyclic phasic contractions after antrectomy, periodic stirring and agitation of gallbladder bile and its mixing with fresh hepatic bile may not occur in the fasting state. The absence of this phenomenon may lead to supersaturation of bile near the mucosal surface and increase the propensity for precipitation of salts and formation of gallstones.

Trichinella spiralis infection alters small bowel motor activity in the fed state

The effect of Trichinella spiralis infection on small intestinal transit and motor activity in the fed state during the intestinal phase of infection was studied. Contractions were recorded by strain gauge transducers, and mean transit time was measured by marker dilution technique. The mean amplitude and area of individual phasic contractions decreased, but no change occurred in their mean duration during trichinosis. The total amplitude and area of phasic contractions also decreased; this was caused by a decrease in the frequency of contractions as well as a decrease in the mean parameters. The reduction in the total duration was entirely caused by the decrease in frequency. The reduction in the total parameters of all contractions was the result of a reduction in the same parameters for both propagating and nonpropagating contractions. However, the decrease in the parameters of propagating contractions was much greater. Also, there was a decrease in the distance of propagation of phasic contractions. The transit time as a result of phasic contractions increased during T. spiralis infection. Additionally, T. spiralis infection induced giant migrating contractions in the fed state that were never observed during control. Chyme was propelled very rapidly and effectively by giant migrating contractions. The findings of the present study suggest that during diarrhea induced by T. spiralis infection, the phasic contractions may act to decrease transit and, hence, allow more contact time for absorption of water and nutrients. However, this response may be counter-balanced by giant migrating contractions that rapidly propel chyme into the colon and compound the diarrhea associated with T. spiralis infection.