Comparison of small‐bowel motility of the human jejunum and ileum

Background Knowledge about human cyclic fasting motility (MMC) and the postprandial response is mostly based on manometric findings in the upper small intestine. Hardly any data exist on human ileal motility, as the acquisition of data has been limited by methodological concerns. The aim was to study human jejunal and ileal motility in an optimized manometric setting. Methods Solid‐state 24‐h‐manometry was performed in the jejunum and ileum of healthy individuals, applying a strict protocol for fasting, resting, and the consumption of a standardized meal. Both visual qualitative and validated computerized quantitative contraction and propagation analysis were performed. Key Results MMC occurs in similar frequency in the jejunum and ileum, but it was significantly shorter in the jejunum at night. By many characteristics, ileal motility was less intense and propagative than jejunal: less migrating clustered contractions, and slower propagation velocity and shorter distance in phases II and III, and postprandially – possibly slowing and enhancing nutrient absorption. Prolonged propagated contractions in some individuals were identified as a unique ileal propulsive pattern. Postprandially, an abrupt conversion to a digestive motility pattern occurs simultaneously independent of the region. Conclusions & Inferences We found similar basic phenomena of fasting and postprandial motility in the jejunum and ileum of healthy humans. However, different calibration of propagative and contractile activity and special motor events in the ileum may account for a different physiological role in digestion. Future studies of small‐bowel motility in healthy and diseased subjects focusing on segmental differences of proximal and distal intestine may be rewarded.     

Effects of enteral infusion of nutrients on canine intestinal motor-patterns

Little is known on the effects of enteral nutrition on intestinal motor patterns. In dogs, intestinal motility was recorded with multiple extra-luminal strain-gauges. An elemental diet was infused into the jejunum (0.5–2.5 kcal min^?1) over 6 h. The elemental diet or dog food were also administered orally for comparison. Jejunal infusion of the elemental diet stimulated jejunal motility; the motor pattern was characterized by clustered contractions. During enteral feeding, stimulation of jejunal motility was initially less (lower motility index, lower incidence of contraction waves and shorter spread of contractions) compared with oral feeding. Jejunal motility declined linearly with time, the decline being less profound during enteral than after oral feeding. Linear correlations also existed between motility parameters and energy loads; increasing energy loads produced reduction instead of enhancement of motility. Strong inhibition of motility followed by vomiting occurred with energy loads ≥ 2 kcal min^?1. The following conclusions were reached: (a) jejunal feeding evoked different patterns of jejunal motility compared with oral feeding; (b) jejunal motility was the result of both a local stimulation and an inhibitory feedback mechanism; (c) intestinal overload of nutrients was indicated by marked inhibition of motility. These results indicate that recording of motility during enteral nutrition might be a useful diagnostic tool for predicting gastrointestinal sequelae.     

Ambulatory long-term jejunal manometry in diabetic patients with cardiac autonomic neuropathy

Concerning alteration of small bowel motility in diabetic patients with autonomic neuropathy controversial data were obtained with stationary manometry and over a limited period of time. The aim of our study was to examine ambulatory 24 h jejunal motility in 15 diabetic patients with cardiac autonomic neuropathy compared with data obtained in 50 healthy controls. Twenty-four hour motility was recorded in the proximal jejunum with a portable datalogger and tube-mounted miniature pressure sensors. Diurnal and nocturnal fasting motility and the motor response to a standardized evening meal of 600 kcal were evaluated by visual and computer-aided analysis. The following abnormalities were found during fasting motility (n = number of patients): absence of phase III over 24 h (n = 2), retrograde migration or simultaneous occurrence of phase III (n = 5). During postprandial motility irregular bursts with tonic baseline elevation (n = 3) and contraction frequencies below the range of controls (n = 8) occurred. Furthermore patients exhibited an inversion of the normal relationship between phase I and phase II during nocturnal MMC – cycles, and discrete clustered contractions were diminished (P < 0.01) in the fasting and digestive state. All patients showed at least one abnormal manometric finding. We conclude that small bowel motility in diabetic autonomic neuropathy is characterized by disturbances in the generation and aboral migration of phase III, an altered circadian variability of the MMC cycle and by postprandial hypomotility.     

Gastrointestinal motor activity associated with postoperative ileus and emesis

The gastrointestinal motor activity associated with post-operative ileus and emesis has not been fully elucidated. This study has evaluated gastric and small-bowel motility in six patients before and after cholecystectomy and in six healthy volunteers, by solid-state manometry. Nausea and vomiting were recorded post-operatively. After surgery, fasting motor abnormalities including (a) total gastric quiescence and (b) small-bowel ‘phasic-bursts’ of contractions were observed in all patients. Phasic bursts (PB) resembled phase III of the migrating motor complex (MMC) on initial visual inspection, but further analysis revealed that they were of shorter duration (3.4 ±.2 min [PB] vs 6.4 ± 0.8 min [MMC], [mean ± SEM] P < 0.01), lower contraction frequency (6.4 ± 0.1 contractions min ^?1 [PBj vs 10 ± 0.3 contractions min^?1 [MMC] [mean ± SEM] P < 0.01) and shorter periodicity (36.4 ± 3 min [PB] vs 70.0 ± 6 min [MMC] [mean ± SEM] P < 0.01). Four patients experienced nausea during phasic burst activity. Vomiting was only observed in association with retrograde phasic-bursts, which migrated through the duodenum to the stomach. This study has shown consistent gastrointestinal motor abnormalities in the immediate post-operative state.     

Cisapride does not modify equine gastrointestinal motility disrupted by E. coli endotoxin or prostaglandin E2

Cisapride, E.coli endotoxin and prostaglandin E₂ were administered intravenously to ponies in which strain gauges had been attached to the stomach and proximal jejunum in order to test if cisapride could modify motility patterns induced by endotoxin or PGE₂- Endotoxin at a dose of 0.1 μg kg^?1 and PGE₂ at a dose of 10 μg kg^?1 produced decreases in gastric motility and jejunal phase-II motility with short intervals between jejunal phase-Ill-activity fronts. Cisapride at a dose of 0.2 mg kg¹ increased gastric motility and jejunal phase-II activity with increased intervals between jejunal phase-III-activity fronts when given alone, but did not modify the motor effects of endotoxin or PGE₂. Cisapride may be ineffective in improving gastrointestinal motility in clinical cases of equine ileus caused by endotoxaemia.     

Impaired intestinal gas propulsion in manometrically proven dysmotility and in irritable bowel syndrome

Background Intestinal manometry is the current gold standard for diagnosing small bowel dysmotility; however, the functional significance of abnormal manometry is unknown. Our aim was to determine whether, and to what extent, intestinal gas propulsion is impaired in patients with manometrically proven dysmotility compared with healthy controls and patients with IBS. Methods Clearance and tolerance of a jejunal gas load (12 mL min^?1 for 2 h) were measured in 15 patients with severe abdominal symptoms and intestinal dysmotility evidenced by manometry, 15 patients with IBS and 15 healthy subjects. Thereafter, the effect of neostigmine (0.5 mg i.v. bolus) vs placebo (i.v. saline) was tested in six dysmotility patients. Key Results After 2‐h gas infusion, patients with dysmotility developed significantly more gas retention (717 ± 91 mL) than IBS patients (372 ± 82 mL; P = 0.0037) and healthy subjects (17 ± 67 mL; P < 0.0001 vs dysmotility; P = 0.0060 vs IBS). Despite the greater retention in dysmotility patients, abdominal perception (2.5 ± 0.6 score) and distension (7 ± 2 mm girth increment) were similar to IBS (3.9 ± 0.6 score and 7 ± 2 mm, respectively). In dysmotility patients, neostigmine produced immediate clearance of gas, and by 30 min had reduced gas retention (by ?552 ± 182 vs 72 ± 58 mL after saline; P = 0.008), abdominal symptoms (by ?0.8 ± 0.3 score vs 0.3 ± 0.2 after saline; P = 0.019) and distension (girth change ?5 ± 1 mm; P = 0.003 vs?2 ± 2 mm after saline). Conclusion & Inferences Patients with manometric dysmotility have markedly impaired intestinal gas propulsion. In IBS patients, impaired gas propulsion is less pronounced but associated with concomitant sensory dysfunction and poor tolerance of gas retention.     

Characteristic motor patterns of phase II and behaviour of phase III in the fed state

The motor pattern of the phase II of the migration motor complex (MMC) is poorly characterized and it remains to be determined whether it differs from the fed motor-pattern. Furthermore, discrepancy exists on the disruption of ongoing MMCs by feeding, and finally, the understanding of the behaviour of phase Ills during enteral nutrition is incomplete. Therefore, canine intestinal motility was studied after meal and during enteral infusion of nutrients (elemental diet, glucose, maltose, amino acids) or of hypertonic saline (300–1520 mosmol kg^?1). Motility of the proximal, mid- and distal jejunum was recorded with strain-gauge transducers. The motor patterns of the interdigestive phase II, after feeding and during enteral nutrition were analysed by a computer. Additionally, the disruption of the MMC by food and by enteral infusion of nutrients or hypertonic saline was investigated. The inter digestive phase II consisted of three different contractile patterns, clustered contractions, a mixed contractile pattern and non-migrating bursts of propagated contractions (NBPCs). NBPCs differed significantly from the phase III activity in several motility parameters and by the lack of aboral migration. Only small differences existed between the motor patterns of phase II and of the fed state, whereas the motor pattern induced by enteral infusion of an elemental diet differed significantly from that of phase II. Ongoing MMCs of the proximal jejunum often continued to migrate to the mid- and distal jejunum. During enteral infusion of nutrients or of hypertonic saline, phase Ills recurred. The migration of ongoing phase Ills and the recurrence of subsequent phase Ills decreased with increasing caloric or osmotic loads. The following conclusions were reached, (a) The phase II of the MMC is a complex motor-pattern. NBPCs represent a new contractile pattern, (b) The MMC is a characteristic feature of the empty gut. After meal and during enteral nutrition, phase Ills are usually suppressed but they can recur during the digestive period.     

Distinctive gastrointestinal motor dysfunction in patients with MNGIE

Background

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare mitochondrial disease caused by mutations in TYMP, encoding thymidine phosphorylase. Clinically it is characterized by severe gastrointestinal dysmotility associated with cachexia and a demyelinating sensorimotor polyneuropathy. Even though digestive manifestations are progressive and invariably lead to death, the features of gastrointestinal motor dysfunction have not been systematically evaluated. The objective of this study was to describe gastrointestinal motor dysfunction in MNGIE using state-of-the art techniques and to evaluate the relationship between motor abnormalities and symptoms.

Methods

Prospective study evaluating gastrointestinal motor function and digestive symptoms in all patients with MNGIE attended at a national referral center in Spain between January 2018 and July 2022.

Key Results

In this period, five patients diagnosed of MNGIE (age range 16–46 years, four men) were evaluated. Esophageal motility by high-resolution manometry was abnormal in four patients (two hypoperistalsis, two aperistalsis). Gastric emptying by scintigraphy was mildly delayed in four and indicative of gastroparesis in one. In all patients, small bowel high-resolution manometry exhibited a common, distinctive dysmotility pattern, characterized by repetitive bursts of spasmodic contractions, without traces of normal fasting and postprandial motility patterns. Interestingly, objective motor dysfunctions were detected in the absence of severe digestive symptoms.

Conclusions and Inferences

MNGIE patients exhibit a characteristic motor dysfunction, particularly of the small bowel, even in patients with mild digestive symptoms and in the absence of morphological signs of intestinal failure. Since symptoms are not predictive of objective findings, early investigation is indicated.     

Pseudo-obstruction Syndrome in Multiple Sclerosis

Three patients with long-standing multiple sclerosis were found to have clinical features of chronic intestinal pseudo-obstruction consisting of nausea, vomiting, abdominal pain, and distention after meals. Radiographic studies demonstrated dilated loops of bowel without evidence of mechanical obstruction. In addition to standard clinical data, results of jejunal manometry in the patients were compared with those of 10 normal volunteers. Phase III of the migrating motor complex activity fronts occurred in two of the three patients during at least 3 hours of recording. Some contractions exhibited higher than normal amplitudes (>90 mm Hg), but the frequency, mean amplitudes, and motility indices were similar to those recorded in the normal volunteers. After a meal the frequency of contractions was reduced, although the amplitudes were normal to high (>90 mm Hg), and some contractions exhibited a tonic or prolonged component. Postprandial contractions were erratic with periods of intense activity alternating with quiescence. These manometric findings are most compatible with a neuropathic process. When pseudo-obstruction compromised assimilation of orally administered nutrients in these patients, central venous nutrition was required.     

Factors in the Control of Interdigestive and Postprandial Myoelectric Patterns of Canine Jejunoileum: Role of Extrinsic and Intrinsic Nerves

Our aim was to determine the roles of extrinsic and intrinsic (enteric) neural continuity to the jejunoileum in control of postprandial and fasting motility patterns. Four groups of dogs were prepared: control, neurally intact; intrinsic transection, distal duodenal transection to disrupt intrinsic myoneural continuity with jejunum; extrinsic transection, transection of all extrinsic nerves to jejunoileum; and intrinsic/extrinsic transection, disruption of both intrinsic myoneural and extrinsic neural continuity to jejunoileum. Duodenal and jejunal electrodes were placed to monitor motility. After 2 weeks, the dogs were studied while fasting, after meals, and during intravenous infusions of cholecystokinin octapeptide at 0.5μg/(kg · h) and pentagastrin at 2μg/(kg · h). During fasting, although the migrating motor complex (MMC) occurred in each region, coordination between duodenum and jejunoileum was disrupted in intrinsic/extrinsic transection dogs, but only partially in intrinsic transection dogs. Small meals (50 g of liver) interrupted the duodenal MMC in all groups and the jejunoileal MMC only in control dogs. A larger (500-g) meal disrupted the MMC in both regions for comparable durations in all groups. Cholecystokinin octapeptide and pentagastrin inhibited the MMC in duodenum and jejunoileum in all groups. Both intrinsic myoneural and extrinsic neural continuity play a role in regional coordination of interdigestive and digestive gut motility. Both hormonal and neural factors (central, enteric) participate in the regulation of onset of postprandial motor patterns.     

Acute experimental stress evokes a differential gender-determined increase in human intestinal macromolecular permeability

Background Intestinal epithelial dysfunction is a common pathophysiologic feature in irritable bowel syndrome (IBS) patients and might be the link to its clinical manifestations. We previously showed that chronic psychosocial stress induces jejunal epithelial barrier dysfunction; however, whether this epithelial response is gender‐specific and might thus explain the enhanced female susceptibility to IBS remains unknown. Methods Intestinal responses to acute stress were compared in age‐matched groups of healthy women and men (n = 10 each) experiencing low background stress. A 20‐cm jejunal segment, was perfused with an isosmotic solution, and intestinal effluents were collected under basal conditions, for 15 min during cold pain stress and for a 45‐min recovery period. Epithelial function (net water flux and albumin output), changes in stress hormones, and cardiovascular and psychologic responses to cold stress were measured. Key Results Heart rate and blood pressure significantly increased during cold pain stress with no differences between men and women. Adrenocorticotropic hormone and cortisol levels during cold pain stress were significantly higher in men. Basal net water flux and epithelial permeability were similar in men and women. Cold pain stress increased water flux in both groups (72 ± 23 and 107 ± 18 μL min^?1 cm^?1, respectively; F(5, 90) = 5.5; P = 0.003 for Time) and, interestingly, this was associated with a marked increase of albumin permeability in women but not in men (0.8 ± 0.2 vs.?0.7 ± 0.2 mg/15 min; P < 0.0001). Conclusions & Inferences Intestinal macromolecular permeability in response to acute experimental stress is increased in healthy women, a mechanism that may contribute to female oversusceptibility to IBS.     

Spatiotemporal maps reveal regional differences in the effects on gut motility for Lactobacillus reuteri and rhamnosus strains

Background Commensal bacteria such as probiotics that are neuroactive acutely affect the amplitudes of intestinal migrating motor complexes (MMCs). What is lacking for an improved understanding of these motility effects are region specific measurements of velocity and frequency. We have combined intraluminal pressure recordings with spatiotemporal diameter maps to analyze more completely effects of different strains of beneficial bacteria on motility. Methods Intraluminal peak pressure (PPr) was measured and video recordings made of mouse ex vivo jejunum and colon segments before and after intraluminal applications of Lactobacillus rhamnosus (JB‐1) or Lactobacillus reuteri (DSM 17938). Migrating motor complex frequency and velocity were calculated. Key Results JB‐1 decreased jejunal frequencies by 56% and 34% in colon. Jejunal velocities increased 171%, but decreased 31% in colon. Jejunal PPr decreased by 55% and in colon by 21%. DSM 17938 increased jejunal frequencies 63% and in colon 75%; jejunal velocity decreased 57%, but increased in colon 146%; jejunal PPr was reduced 26% and 12% in colon. TRAM‐34 decreased frequency by 71% and increased velocity 200% for jejunum, but increased frequency 46% and velocity 50% for colon; PPr was decreased 59% for jejunum and 39% for colon. Conclusions & Inferences The results show that probiotics and other beneficial bacteria have strain and region‐specific actions on gut motility that can be successfully discriminated using spatiotemporal mapping of diameter changes. Effects are not necessarily the same in colon and jejunum. Further research is needed on the detailed effects of the strains on enteric neuron currents for each gut region.     

Role of Peptide YY in Intestinal and Gallbladder Motility in Dogs

The purpose of this study was to characterize the action of exogenous PYY, an ileocolonic peptide released by fatty meal, and that released by Heal perfusion with oleate on intestinal and gallbladder motility patterns and the posssible role of the adrenergic pathway in this action. Dogs were equipped with chronic duodenal electrodes for recording myoelectric activity and with a cannula in the gallbladder fundus for measuring the gallbladders intraluminal pressure and volume and calculating its motility index (MI) and emptying rate. After intravenous infusion of PYY, there was a dose-dependent prolongation of the migrating motor complex (MMC) interval and almost complete abolition of the contractions and emptying of gallbladder during the duodenal activity front. After meat feeding or during intravenous infusion of cerulein, 50 pmol/(kg · h), the MMC was interrupted and replaced by irregular spike activity, accompanied by a marked increase in the gallbladder MI and about 80% to 90% reduction of its volume. PYY, 200 pmol/(kg · h), reduced significantly the meal- or cerulein-induced duodenal spike activity but failed to affect the MI and volume of the gallbladder. Similar changes in fasted and fed patterns of motility were observed after Heal oleate (16 mM/h), producing plasma PYY levels in a range similar to that observed after infusion of exogenous PYY. The inhibitory effects of PYY or Heal fat on intestinal myoelectric activity were reversed in part by α-adrenergic blockade (phentolamine). We conclude that exogenous PYY or endogenous hormone released by Heal oleate inhibits the interdigestive and postprandial motility pattern of the small bowel but does not affect gallbladder motility, and that the inhibition of intestinal motility involves, at least in part, the adrenergic pathway.     

Does ulnar neuropathy predispose to focal dystonia?

We have observed a high incidence of ulnar neuropathy in musicians with dystonic flexion of the ipsilateral little and ring fingers. To investigate the relationship between ulnar neuropathy and focal dystonia, we compared the patterns of surface EMG activity in extensor digitorum communis (EDC4) and flexor digitorum superficialis (FDS4) during tapping of the ring finger in normal controls and patients with ulnar neuropathy or local dystonia. Ten of 10 normal subjects exhibited wellformed alternating EMG bursts in EDC4 and FDS4 separated by clear silent periods. Seven of 7 patients with dystonic flexion of the little and ring fingers showed loss of silent periods between poorly formed bursts in FDS or EDC. Surprisingly, 9 of 10 patients with ulnar neuropathy showed burst pattern abnormalities qualitatively similar to those observed in the dystonic patients. These data suggest that ulnar neuropathy alters the execution of a motor task involving multiple peripheral nerves. © 1995 John Wiley & Sons, Inc.     

An advanced approach for the assessment of gastric motor function in long-term Type 1 diabetes mellitus with and without autonomic neuropathy

Gastric motor dysfunction is a frequent and deleterious long-term complication in diabetes mellitus (DM) but the exact contribution of diabetic autonomic dysfunction remains unclear. The aim of this study was to assess indices of gastric motor function in long-term Type 1 DM in the light of the presence and absence of autonomic neuropathy by means of an advanced dynamic scintigraphic technique. Gastric scintigraphy with condensed images of a short dynamic sequence was applied to 27 long-term Type 1 diabetic patients (duration > 10 years) and 15 control subjects. Two indices of gastric peristalsis, the frequency of contractions (FC) and amplitude of contractions (AC), were assessed scintigraphically together with half-time of gastric emptying (t 1/2). Five cardiac reflex tests were performed to study electrocardiogram (ECG)-based cardiac autonomic neuropathy (CAN). Mean AC was significantly decreased in diabetic patients compared to control subjects (13 ± 9 % vs. 28 ± 8 %, p < 0.005). Mean FC was comparable between diabetic patients and control subjects (3.1 ± 0.4 min⁻¹ vs. 3.1 ± 0.2 min⁻¹). Compared to control subjects, half-time of gastric emptying was significantly prolonged in diabetic patients (31 ± 17 min vs. 20 ± 3 min, p < 0.001). Mean AC, FC and t 1/2 did not differ significantly between diabetic patients with (n = 10) and without (n = 17) ECG-based CAN. Our study demonstrates that in both long-term Type 1 DM with and without autonomic neuropathy, the amplitude but not the frequency of gastric contractions, is frequently reduced. A delay of gastric emptying in Type 1 DM is confirmed although it was independent from the presence of cardiac autonomic neuropathy (CAN). Analyzing gastric motor function with dynamic scintigraphic techniques using condensed images is a promising clinical approach to further elucidate the mechanisms of impaired gastric motility in DM. Received: 25 July 2001, Accepted: 27 March 2002     

Neural mechanisms of early postinflammatory dysmotility in rat small intestine

Although human postinflammatory dysmotility is known, so far animal studies have primarily investigated changes during inflammation. Here, we focused on postinflammatory changes in rat jejunal myenteric plexus and jejunal motility. Evolution of ethanol/2,4,6-tri-nitrobenzene sulphonic acid (TNBS)-induced inflammation was assessed histologically and by measuring myeloperoxidase activity (MPO). Electromyography and immunohistochemistry were performed 1 week after ethanol/TNBS and also after N(G)-nitro-L-arginine methyl ester (L-NAME) administration. Ethanol/TNBS induced a transient inflammation, with normalization of MPO and histological signs of an early phase of recovery after 1 week. The number of cholinergic neurones was not altered, but myenteric neuronal nitric oxide synthase (nNOS)-immunoreactivity was significantly lower in the early phase of recovery after TNBS compared with water (1.8 +/- 0.2 vs 3.5 +/- 0.2 neurones ganglion(-1), P < 0.001). Interdigestive motility was disrupted with a loss of phase 1 quiescence, an increase of migrating myoelectric complex cycle length, a higher number of non-propagated activity fronts and a decrease of adequately propagated phase 3 s after TNBS. Administration of L-NAME resulted in a similar disruption of interdigestive motility patterns. In the early phase of recovery after ethanol/TNBS-induced jejunal inflammation, a loss of motor inhibition occurs due to a decrease of myenteric nNOS activity. These observations may provide a model for early postinflammatory dysmotility syndromes.     

A novel portable perfused manometric system for recording of small intestinal motility

The development of solid-state catheters with miniature pressure transducers and portable dataloggers with a large memory capacity has allowed recording of gastrointestinal motility in ambulant subjects. Developments in silicone rubber extrusion technology made it possible to build a perfused mano-metric system, using a perfused manometric assembly requiring a low volume of perfusate. In the present study the feasibility of recording and automated analysis of small intestinal motility using a perfused multiple lumen manometric system was evaluated in seven healthy volunteers. Pressures were recorded from 12 sideholes arranged in four clusters spaced at 10-cm intervals from the catheter tip. Each channel was perfused at 0.15 mL min⁻¹ with degassed water by a portable, low-compliance, perfusion pump. The 12 sidehole recording channels were connected to external transducers mounted on a belt. Pressure data were stored in two dataloggers. Motility was recorded in the sitting (30 min), and supine (30 min) position, during walking (30 min) and postprandially (90 min). Using purpose-built software baseline variations were corrected for and manometric variables (number of pressure waves, mean amplitude and motility index) calculated. Bench testing of the manometric assembly showed a median baseline pressure offset of 4.2 kPa (range 3.7–10.1) and upon occlusion a rise rate of 27.8 kPa sec⁻¹ (range 19.7–30.8). Changes in body position affected baseline pressures so that compared to the supine position changes in baseline pressure varied between 1.5 ± 0.7 kPa and 1.9 ± 0.6 kPa during sitting (P < 0.02), and between 1.7 ± 0.7 kPa and 1.5 ± 0.9 kPa during walking (P < 0.03). Manometric recordings obtained during the fasting period showed an increase in small intestinal motor activity during walking. In the postprandial period no differences in motility variables were observed within one cluster and in time. Recording of small intestinal motility with a multiple-channel silicone rubber manometric assembly with a portable perfusion system is a feasible technique which is relatively inexpensive. Computer-assisted data processing allows for adequate elimination of artefacts and automated numerical analysis.     

Progressive muscular relaxation and motility of the small intestine: studies in normal subjects and patients with irritable bowel syndrome

Recordings of fasting duodenojejunal motor activity were obtained during a controlled 20-min period of psychological relaxation in 10 patients with irritable bowel syndrome (IBS) and 10 healthy subjects. The IBS group showed a significant decline in their level of arousal (on both cardiovascular and subjective measures) in response to relaxation; such alterations were minimal in the control group. Both groups, however, demonstrated significant inhibition of phase 2 activity (motility index, contractile frequency and amplitude) of the migrating motor complex in response to relaxation, and the magnitude of the response did not differ between the two groups. Clustered contractile activity present in 4 IBS patients was also suppressed during the relaxation period. There were no correlations between changes in the level of arousal and the degree of motor suppression in either IBS patients or controls. These findings demonstrate that psychological relaxation therapy can profoundly influence patterns of small bowel motility, and shed light on the mechanisms by which psychological intervention therapy appears to be effective in IBS.     

Effect of nitric oxide on propagated clusters of spontaneous motor waves in an ex vivo rabbit intestinal preparation

The aim of this study was to determine whether nitric oxide can play a role in regulating the propagation of spontaneous motor activity in a rabbit intestinal preparation completely excluded from any central and vascular connection. Experiments were done on nine rabbits of either sex, weighing 2.5 ± 0.5 kg (mean ± SD). After one week of semiliquid diet the animals were sacrificed and a segment including the stomach, duodenum and part of the jejunum was removed and placed into a single chamber organ bath containing 1 L of oxygenated Krebs' solution. Four strain gauges connected to a Dynograph Recorder were sutured on the serosal surface 10 cm apart starting from the gastric antrum to the distal duodenum. Once the motor activity was stabilized, N-nitro-L-arginine methyl-ester (L-NAME) was added to the bath at increasing concentration from 10^?7 to 10^?4. Spontaneous motor activity was recorded, characterized by the cycling occurrence of bursts of waves, starting from the stomach and propagating to the descending duodenum. L-NAME at higher concentrations reduced the time interval between the bursts of waves with a concomitant increase in the propagation velocity of the motor activity. No change in the frequency of waves was detected. The effect of L-NAME was prevented by the administration of L-Arginine. This study suggests an important role for the nitric oxide pathway in the distal propagation of the spontaneous motor activity of the alimentary tract.