Colonic myoelectrical activity in IBS painless diarrhoea

Clinical, psychological, and physiological correlates of patients who defecate after meal

BACKGROUND AND AIMS

Food is the most important synchronizer of gastrointestinal motility and secretion. Many patients with functional bowel or anorectal disorders complain of fecal urge and stool output after eating.

PATIENTS AND METHODS

In this prospective observational study, 408 consecutive outpatients with functional bowel and/or anorectal disorders (74% female, 50.2±15.6 years, 24.8±5.0 kg/m²) filled Rome III questionnaires. Depression and anxiety scores, a physiological evaluation (total and segmental colonic transit time, colonic transit response to eating using a standard 1000 kcal test meal, and anorectal manometry), were measured. Univariate analysis and multivariate logistic regression were carried out according to the presence or not of stool output after eating.

RESULTS

Defecation after eating was found in 21% of patients. These patients were not different according to the demographic characteristics of sex ratio (P=0.702), age (P=0.830), and BMI (P=0.314). In contrast, they had lower state anxiety (P=0.032), but similar scores of depression (P=0.240) and trait anxiety (P=0.933). They had similar manometric characteristics (anal pressure and rectal sensitivity), but a greater response to eating in all segments of the colon. There was an increase in the frequency of functional diarrhea (odds ratio=2.576, 95% confidence interval=1.312-5.056; P=0.006) and levator ani syndrome (odds ratio=2.331, 95% confidence interval=1.099-4.944; P=0.017), but no other functional bowel disorder including irritable bowel syndrome and its subtypes was found.

CONCLUSION

Stool output after eating is associated with clinical disorders but not physiological parameters. This symptom is not associated with irritable bowel syndrome, but a higher frequency of functional diarrhea.

Is the colonic response to food different in IBS in contrast to simple constipation or diarrhea without abdominal pain?

BACKGROUND

Colonic response to food (CRF) is abnormal in irritable bowel syndrome (IBS) patients.

AIMS

The aim of this study was to compare CRF in patients who complain of abnormal defecation pattern according to the presence or absence of abdominal pain.

METHODS

One hundred forty-nine patients and 50 controls were studied: 96 IBS patients (46 IBS-C, 13 IBS-D, 15 IBS-M, and 22 IBS-U not included), 43 patients with functional constipation (group C) and ten with functional diarrhea (group D). Clinical evaluation and visual analog scales about four items (constipation, diarrhea, abdominal bloating and abdominal pain) were filled by all subjects. Colonic transit time (CTT) was measured in fasting conditions and after eating a standard 1,000-cal test meal. CRF was quantified by calculating the variation in number of markers between the two films.

RESULTS

The frequency of meal-related symptoms did not vary among the different groups of patients but was significantly higher than in controls. Compared to IBS-C patients, constipated patients of the group C had longer total and segmental colonic transit time, and compared to IBS-D patients, diarrheic patients of the group D had shorter oro-anal and segmental colonic transit time except in the recto-sigmoid area. CRF was different in patients and controls, and differed between IBS and non IBS patients with similar transit abnormalities. Stool output was greater in patients of the group D than in patients of the IBS-D group.

CONCLUSION

The different subgroups of IBS patients have different CRF patterns, distinct from subjects with constipation and diarrhea, but without abdominal pain.

Spectral analysis of colonic intraluminal pressure in patients who received a colonic replacement following radical esophagectomy

The aim of this study was to evaluate the motor activity of the interposed colonic segment in patients who had received a colonic replacement following radical esophagectomy using spectral analysis and a 24 hr activity graph. The 24-hr ambulatory pressure waves were recorded in the replaced colon after esophagectomy (n=8) using a solid-state manometric catheter (MicroDigitrapper, Synetics). Motility and spectral analyses of the intraluminal pressure waves were performed by Multigram and Gastrosoft (Synetics). It was revealed that after a meal the 3 cpm (cycles per minute) component of the motility index increased but the 12-15 cpm component decreased. The diurnal rhythm showed that colonic motility was high in the daytime and low during sleep. In contrast, duodenal motility was relatively high even during sleep. The motility index increased as the postoperative period increased. The motility of the replaced colon was higher during the daytime and after meals. The higher motility after meals was characterized by an increase in the 3 cpm component. These motor characteristics may help the function of the replaced colon as a substitute for the esophagus.

The effect of motilin on the rectum in healthy volunteers

AIMS

The role of motilin in the regulation of upper gastrointestinal (GI) motility is well defined. However, little is known about the effects on the distal GI tract. To investigate the effect of exogenous motilin on rectal function, barostat measurements in the rectum were performed and lower abdominal symptoms were scored.

METHODS

Eight fasted, healthy volunteers were infused intravenously with synthetic motilin or placebo over 90 min in a double-blind, randomized, cross-over design. Rectum volume was measured with a barostat device during constant pressure and during isobaric distensions. Lower abdominal symptoms were scored by visual analogue scales. Plasma motilin concentrations were measured by radioimmunoassay.

RESULTS

Baseline rectum volumes were similar between treatments: 185 +/- 62 mL (motilin) and 136 +/- 41 mL (placebo). During the constant pressure procedure, motilin increased rectum volume [area under the effect curve (AUEC)] by 6%[95% confidence interval (CI) -3, 16] of baseline, compared with placebo. During isobaric distensions motilin increased rectum volume (AUEC) by 43 mL (95% CI 0.4, 85; P < 0.05) and compliance by 10 mL mmHg-1 (95% CI 0.3, 20; P < 0.05) relative to placebo. Motilin did not induce changes in the sensation of rectal feelings.

CONCLUSION

Exogenous motilin increased rectal compliance in healthy volunteers, without affecting rectal sensations.

Celiac disease-like abnormalities in a subgroup of patients with irritable bowel syndrome

BACKGROUND & AIMS

Abdominal symptoms in the absence of mucosal abnormalities are features of both the irritable bowel syndrome (IBS) and latent/potential celiac disease (cd). To identify a possible subgroup of IBS patients with latent/potential cd, surrogate markers of cd were investigated in IBS patients.

METHODS

IBS patients suffering from diarrhea (n = 102), and patients with active cd (n = 10), treated cd (n = 26), and latent cd (n = 5) were included in the study. We measured serum immunoglobulin (Ig) A against gliadin and tissue-transglutaminase, and IgA and IgM against gliadin, tissue-transglutaminase (intestinal cd-associated antibodies), and the dietary proteins beta-lactoglobulin and ovalbumin in duodenal aspirate by enzyme-linked immunosorbent assay. Intraepithelial lymphocytes (IELs) were counted in histology sections, and the expression of HLA-DQ2 (A1*0501/B1*0201) was investigated by polymerase chain reaction. In 26 IBS patients, the effect of 6 months of gluten withdrawal was examined.

RESULTS

Most cd patients expressed HLA-DQ2 and had increased intestinal cd-associated antibodies, whereas cd-associated serum IgA and IEL counts were increased in active cd in contrast to treated or latent cd. In IBS patients, 35% were HLA-DQ2-positive, 23% had increased IEL counts, and 0% and 30% had increased cd-associated antibodies in serum and duodenal aspirate, respectively. Furthermore, stool frequency and intestinal IgA decreased significantly under a gluten-free diet in the subgroups of HLA-DQ2-positive and intestinal antibody-positive IBS patients when compared with IBS patients without these markers.

CONCLUSIONS

HLA-DQ2 expression and increased intestinal cd-associated antibodies are markers that can identify latent/potential cd in a subgroup of IBS patients who consequently appear to profit from a gluten-free diet.

Intrarectal injection of glycerol induces hypersensitivity to rectal distension in healthy subjects without modifying rectal compliance

BACKGROUND

Rectal sensory thresholds are lowered in patients with irritable bowel syndrome (IBS), reflecting visceral hyperlagesia, which might be related to subclinical inflammation.

AIM

To evaluate the effects of an intraluminal injection of glycerol, a mucosal irritant, on rectal tone and perception of distension in 12 healthy subjects.

METHODS

Rectal tone was evaluated with a barostat. First sensation, need to defecate and pain thresholds were evaluated during isobaric phasic distensions, before and 20 and 120 min after injection of 10 ml glycerol in the rectum.

RESULTS

Baseline bag volume (97.9 +/- 56.2 ml) significantly decreased 20 min (49.7 +/- 42.2 ml; P= 0.026) and 120 min (66.5 +/- 38.3 ml; P= 0.050) after injection of glycerol, indicating its hypertonic effect. The pressure defining sensory thresholds was decreased significantly 20 min after glycerol injection: first sensation, 14.6 +/- 2.9 versus 18.3 +/- 7.2 mm Hg (P = 0.01); need to defecate, 19.6 +/- 3.7 versus 26.0 +/- 6.9 mm Hg; pain, 23.8 +/- 4.5 versus 35.6 +/- 9.5 mm Hg (P = 0.001). This effect was maintained for 120 min after injection of glycerol. Slopes of the compliance curves did not differ before and after injection of glycerol.

CONCLUSIONS

Intraluminal injection of glycerol significantly increases rectal tone and sensitizes healthy volunteers to rectal distension, since they show significantly lower thresholds after glycerol. This could constitute a model of visceral hypersensitivity in healthy volunteers.

Alterations of intestinal motor responses to various stimuli after Nippostrongylus brasiliensis infection in rats: role of mast cells

Nippostrongylus brasiliensis infection induces jejunal mastocytosis associated with enteric nerve remodelling in rats. The aim of this study was to evaluate the intestinal motility responses to meals and to neurotransmitters involved in the control of gut motility (acetylcholine (carbachol), substance P and neurokinin A) in both control and N. brasiliensis-infected rats 30 days post-infection. All rats were equipped with NiCr electrodes in the jejunum to record myoelectrical activity. The duration of disruption of the jejunal migrating myoelectrical complexes (MMC) induced by the different stimuli was determined. Meal ingestion and substance P administration disrupted the MMC pattern for similar durations in the two groups. Carbachol and neurokinin A induced a significantly longer MMC disruption in post-infected rats than in controls (125 +/- 8.3 vs. 70 +/- 6 min for carbachol 100 microg kg-1 and 51 +/- 4 vs. 40 +/- 2 for neurokinin A 50 microg kg-1). The enhanced motor response in postinfected rats was reduced by previous mast cell stabilization with ketotifen or mast cell degranulation with compound BrX 537 A. In conclusion, the increased intestinal motor reactivity to carbachol and neurokinin A in post-N. brasiliensis-infected rats depends upon intestinal mast cell hyperplasia and degranulation.

The kappa agonist fedotozine relieves hypersensitivity to colonic distention in patients with irritable bowel syndrome

BACKGROUND & AIMS

Visceral hypersensitivity plays a major role in the pathophysiology of inflammatory bowel syndrome (IBS). Opioid kappa receptors on afferent nerves may modulate it and may be the target of new IBS treatments. The aim of this study was to evaluate the effects of fedotozine, a potent and selective kappa agonist, on responses to colonic distention and colonic compliance in patients with IBS.

METHODS

Fourteen patients with IBS (Rome criteria; 50 +/- 12 years; 6 men and 8 women) were included in a randomized double-blind, crossover trial comparing the effect of an intravenous infusion of 100 mg fedotozine or saline on sensory thresholds elicited by left colon phasic distention (4-mm Hg steps for 5 minutes) up to a sensation of abdominal pain. Colonic compliance was compared by the slope of the pressure-volume curves built on placebo and on fedotozine.

RESULTS

In the fedotozine group, thresholds of first perception (28.7 +/- 5.9 mm Hg) and pain (34.7 +/- 5.5 mm Hg) were significantly greater than with placebo (23.3 +/- 4.5 and 29.0 +/- 3.5 mm Hg, respectively; P = 0.0078). Colonic compliance was 9. 20 +/- 3.87 mL. mm Hg-1 with placebo and 8.73 +/- 3.18 mL. mm Hg-1 with fedotozine (not significant).

CONCLUSIONS

Fedotozine increases thresholds of perception of colonic distention in patients with IBS without modifying colonic compliance. Fedotozine seems capable of reversing visceral hypersensitivity observed in these patients and could have some beneficial action on their symptoms.

Effect of alosetron on responses to colonic distension in patients with irritable bowel syndrome

BACKGROUND

Visceral hypersensitivity plays a major role in the pathophysiology of irritable bowel syndrome, as shown by balloon distension studies. 5-HT3 receptors on afferent nerves may modulate visceral sensitivity and be the target of new treatments for irritable bowel syndrome.

AIM

To evaluate the effects of alosetron, a potent and selective 5-HT3 antagonist, on the perception of colonic distension by patients with irritable bowel syndrome, and on the colonic compliance to distension with a barostat.

METHODS

Twenty-five irritable bowel syndrome patients were included in a randomized double-blind parallel group trial; data were available for 22 (Rome criteria; 48 +/- 11 years: 13 men and nine women). Patients were treated for 7 days with placebo (n = 6), alosetron 0.25 mg b.d. (n = 8) or alosetron 4 mg b.d. (n = 8). On day 6, a barostat bag was placed in the left colon. On day 7, after an overnight fast, isobaric phasic distensions were performed (4 mmHg steps, 5 min) up to the step triggering a sensation of abdominal pain.

RESULTS

Groups were comparable at inclusion (age, sex, symptoms, bowel habits). There were no differences between treatment groups in pressure recorded within the bag at the time of first sensation of abdominal pain. However, bag volumes were significantly increased. At the first sensation threshold, median volume differences of 61 mL and 90 mL (P = 0.028) were recorded with alosetron 0.25 mg b.d. and 4 mg b.d., respectively. At the threshold of abdominal pain, these differences were 71 mL (P = 0.039) and 84 mL (P = 0.017). Colonic compliance increased from 5.9 mL/mmHg on placebo to 7.6 mL/mmHg on alosetron 0.25 mg b.d. and to 9.8 mL/mmHg (P = 0.034) on alosetron 4 mg b.d.

CONCLUSION

Alosetron increases the compliance of the colon to distension, and could thereby contribute to changes in perception of colonic distension and improvement in the symptoms of irritable bowel syndrome.

The distal colon provides reserve storage capacity during colonic fluid overload

BACKGROUND

In addition to its absorptive function the capacity of the colon to retain fluid might be relevant in compensating for increased fluid loads and prevention of diarrhoea. The distal colon is considered to be mainly a conduit without extensive storage function.

AIMS

To evaluate colonic volume capacity in a model of pure osmotic diarrhoea.

METHODS

A non-absorbable, iso-osmotic solution (OS) containing polyethylene glycol (500 ml) was infused into the caecum of nine healthy volunteers; the control group (n = 5) received an equal amount of an easily absorbable electrolyte solution (ES). Fluids were radiolabelled with technetium-99m and gamma camera images were obtained for 48 hours. Counts in the proximal and distal colon were measured and regional and overall colonic transit and stool output were quantified.

RESULTS

After OS, in contrast to ES, faecal output was increased significantly (p < 0.05), but colonic transit after OS was not different from transit after ES (p > 0.05). This indicates storage of OS in the colon: after OS infusion, counts in the proximal colon decreased linearly while the distal colon stored approximately 30% of radioactivity for the whole 48 hour study period. After OS, stool output correlated with distal (p < 0.01), but not with proximal (p > 0.05), colonic transit. In contrast, after ES, stool output was determined by proximal colonic transit (p < 0.05) but not by transit through the distal colon (p > 0.05).

CONCLUSION

The distal colon retains non-absorbable fluid volumes extensively. In our model transit through the distal colon--but not the proximal colon--determined the time at which diarrhoea occurred.

Oxytocin increases thresholds of colonic visceral perception in patients with irritable bowel syndrome

AIM

The effects of oxytocin on colonic perception of intraluminal distension were evaluated in 26 patients with irritable bowel syndrome (IBS), using a flaccid bag placed in the descending colon and connected to a computerised barostat.

METHOD

Symptomatic responses (first sensation and pain) were evaluated during isobaric distensions (4 mm Hg increments, five minute duration, five minute interval with return to zero pressure between each step), performed automatically by the barostat, during a continuous infusion of placebo or various doses of oxytocin (10, 20, 30, and 50 mU/min).

RESULTS

The distension pressure (mean (SD)) required to induce a first abdominal sensation was 17.3 (5.5) mm Hg on placebo, 19.9 (5.8) on oxytocin 10 mU/min (NS), 22.3 (6.0) mm Hg on oxytocin 20 mU/min (p < 0.01), 23.1 (6.6) mm Hg on oxytocin 30 mU/min (p < 0.01), and 24.0 (7.1) mm Hg on oxytocin 50 mU/min (p < 0.01). The distension pressure required to induce pain was 24.8 (6.3) mm Hg on placebo, 26.0 (5.8) on oxytocin 10 mU/min (NS), 33.3 (7.8) mm Hg on oxytocin 20 mU/min (p < 0.01), 34.2 (7.6) mm Hg on oxytocin 30 mU/min (p < 0.01), and 34.3 (7.9) mm Hg on oxytocin 50 mU/ min (p < 0.01). Compliance curves were not different after placebo and oxytocin injection at the different doses. Naloxone did not inhibit the effect of oxytocin. Oxytocin also did not alter somatic perception, characterised by the RIII reflex at the level of the biceps femori.

CONCLUSIONS

Oxytocin significantly increases thresholds for visceral perception in IBS patients at doses equal or to greater than 20 mU/min, possibly by acting at the level of visceral afferents.

Octreotide increases thresholds of colonic visceral perception in IBS patients without modifying muscle tone

Effects of octreotide (1.25 micrograms/kg subcutaneously) on colonic tone and visceral perception were evaluated in 10 IBS patients, using a barostat and compared to placebo in a double-blind crossover study. Colonic sensory thresholds were also studied in healthy controls for comparison with IBS patients. Colonic tone was reflected by variations in volume of the barostat balloon. Baseline volume was 117 +/- 38 ml and was not modified by placebo (122 +/- 40 ml) or octreotide (106 +/- 42 ml). After the meal, maximal decrease in balloon volume was 75 +/- 4% following placebo (P < 0.001) beginning after 9 +/- 3 min and lasting 136 +/- 17 min. Following octreotide, the maximal decrease was 69 +/- 16% (NS vs placebo), after 10 +/- 3 min and lasting 140 +/- 22 min. In the second part, discomfort and pain thresholds were evaluated during isobaric distensions (4 mm Hg increments, 5-min duration, 5-min interval with return to pressure 0 between each). The pressure inducing discomfort was 21.2 +/- 5.9 mm Hg following placebo vs 29.6 +/- 6.6 mm Hg following octreotide (P < 0.01). The pressure inducing pain was 24.8 +/- 7.3 mm Hg following placebo vs 33.2 +/- 7.3 mm Hg following octreotide (P < 0.01). In healthy subjects, discomfort and pain were induced by colonic distensions at a mean intraballoon pressure of 32.7 +/- 5.8 mm Hg and 36.7 +/- 3.9 mm Hg, respectively. Compliance curves were not different following placebo and octreotide. Octreotide significantly increases thresholds for visceral perception in IBS patients without modifying compliance during distension nor colonic tone.

Evaluation of colonic sensory thresholds in IBS patients using a barostat. Definition of optimal conditions and comparison with healthy subjects

To study the role of abnormal visceral perception in the pathophysiology of the irritable bowel syndrome (IBS), we evaluated colonic tone and visceral perception during intracolonic distension using a flaccid balloon connected to a computerized barostat and placed in the descending colon of IBS patients and healthy controls. In the first part of the study, basal colonic tone and response to pharmacological (neostigmine and glucagon) and physiological (1000-kcal meal) stimuli were recorded in nine IBS patients. Colonic tone increased by 72 +/- 27% after injection of neostigmine and decreased by 88 +/- 62% after glucagon. After the meal, the maximal increase in colonic tone was 76 +/- 31% with the total response to the meal lasting 109.7 +/- 32.0 min. In the second part of the study, symptomatic responses (discomfort and pain thresholds) and pressure variations were evaluated during two different methods of distension (stepwise and intermittent) in a randomized order in the nine IBS patients and six healthy controls. Each distension method was repeated twice in IBS patients to study reproducibility. In IBS patients, the mean discomfort threshold volume was 172 +/- 76 ml when using stepwise and 167 +/- 43 ml when using intermittent distension. The mean pain threshold volume was 250 +/- 25 ml when using stepwise and 211 +/- 22 ml when using intermittent distension, this difference being statistically significant (P < 0.02). Discomfort and pain threshold volumes recorded during the first session of the same distension method were not different from those recorded during the second one.(ABSTRACT TRUNCATED AT 250 WORDS)

Motility of rabbit proximal colon. Relevance of cholinergic pathways and role of different muscarinic receptor subtypes

To better define the physiologic relevance of the cholinergic muscarinic input to the rabbit colon and the role of different muscarinic receptor subtypes, we studied the effects of atropine, telenzepine (MI antagonist) and DF594 (M3 antagonist) on colonic motility in eight conscious rabbits fitted with bipolar electrodes and strain gauges along the proximal colon. In some experiments, the chronotropic and mydriatic effect of the pharmacological agents were also assessed. Two main patterns of spike activity were identified: short spike bursts (SSBs), which were usually stationary, and long spike bursts (LSBs), which were usually propagated. Both myoelectrical patterns were dose-dependently inhibited by atropine (0.06-4 mumol/kg). Atropine, at the doses of 2-4 mumol/kg, abolished both myoelectrical and mechanical activity. Telenzepine (0.008-0.125 mumol/kg) dose-dependently inhibited migrating LSBs without significant effect on SSBs. Higher doses (0.25-0.5 mumol/kg) inhibited both LSBs and SSBs. DF594 (0.06-2 mumol/kg) dose-dependently inhibited both migrating LSBs and SSBs. The three antimuscarinic agents, at doses that inhibited colonic spike activity by approximately 80% (equiactive doses), behaved as follows on heart rate and pupil diameter: atropine induced tachycardia and mydriasis, telenzepine had no effect, and DF594 induced slight mydriasis with no effect on heart rate. We conclude that spontaneous motility in the rabbit proximal colon depends on a muscarinic excitatory input. M3 receptors are involved in the control of both LSBs and SSBs, while M1 receptors play an important role in the regulation of LSBs. The development of selective antimuscarinic drugs, acting on a given motility pattern and with minimal side effects, may offer new perspectives in the treatment of functional bowel motor disorders.

Physiology and pathophysiology of colonic motor activity (2)

The basic motor function of the colon is to mix and knead its contents, propel them slowly in the caudad direction, hold them in the distal colon until defecation, and provide a strong propulsive force during defecation. Infrequently, it also produces mass movements in the proximal colon. These motor functions are achieved in most species by three different types of contractions: the individual phasic contractions that include the short- and long-duration contractions, organized groups of contractions that include the migrating and nonmigrating motor complexes, and special propulsive contractions (giant migrating contractions). The spatial and temporal patterns of all of these contractions are controlled by myogenic, neural, and chemical control mechanisms. The individual phasic contractions are highly disorganized in time and space in the colon. For this reason, they are effective in mixing and kneading and slow distal propulsion. The underlying cause of the disorganization of short duration contractions is the irregularity in the frequency and waveshape of colonic electrical control activity and its phase unlocking throughout the colon. The individual contractions in many species occur in cyclic bursts called contractile states. At least in some species, these contractile states exhibit mostly caudad and sometimes orad migration. However, there are also nonmigrating or randomly migrating contractile states in the colon. These two patterns of contractile states are called colonic migrating motor complexes and colonic nonmigrating motor complexes, respectively. The giant migrating contractions provide the strong propulsive force for defecation and mass movements. The neural control of colonic contractions is organized at three levels--enteric, autonomic, and central. The enteric nervous system contains cholinergic and peptidergic neurons and plays a major role in the control of colonic contractions. The autonomic nerves, the vagi, pelvic, lumbar colonic, hypogastric, and splanchnic nerves, seem to continuously monitor the state of the colon and provide a modulatory input when necessary. These nerves play a major role in the reflexive control of colonic motor function. The voluntary input from the central nervous system coordinates the motor activity of the colon, rectum, anal canal and sphincters for orderly evacuation of feces during defecation. The role of acetylcholine, nonadrenaline, and the yet to be completely identified nonadrenergic, noncholinergic neurotransmitter, possibly VIP, in the control of contractions is fairly well established. Besides these, there are several other peptides and chemicals that are localized in the colonic wall; their physiological roles remain unknown. Colonic motor activity has been studied in several disease states. The findings have not always been consistent.(ABSTRACT TRUNCATED AT 400 WORDS)

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

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

Inflammatory bowel disease and irritable bowel syndrome

The irritable bowel syndrome accounts for 30 to 50 per cent of patients cared for by gastroenterology practices. Irritable bowel syndrome is more common than inflammatory bowel disease. Therefore, it should not be surprising that some patients with inflammatory bowel disease are initially told that they have irritable bowel syndrome before a diagnosis of inflammatory bowel disease is firmly established. This article contends that many people have both irritable bowel syndrome and inflammatory bowel disease.

Effects of sennosides on colonic myoelectrical activity in man

The effects of sennosides on colonic myoelectrical activity were investigated in man. Spiking activity of the left and sigmoid colons was continuously recorded in seven constipated patients during two sessions from 5:00 PM to 9:00 AM. Each patient received orally at 7:00 PM on two consecutive days 30 mg of sennosides one day (sequence S) and placebo on the other (sequence P) in a random fashion. A significant (P less than 0.05) increase of peristaltic activity (migrating long spike bursts or MLSBs) after sennosides was observed between 1:00 and 7:00 AM, and a corresponding decrease between 7:00 and 9:00 AM. No change was noted in total short spike burst (SSB) activity or in SSBs characteristic of the rectosigmoid area. This study indicates that the main modification of colonic motility induced by sennosides was a stimulation of propulsive activity (MLSBs), which occurred between 6-12 hr after oral administration, the delay required for orocecal transit and metabolism of the drug.

Inhibition of the colonic motor response to eating by pinaverium bromide in irritable bowel syndrome patients

The effect of pinaverium bromide on the colonic motor response to eating was investigated in 10 irritable bowel syndrome patients, by means of an intraluminal probe supporting 8 groups of electrodes. At each site examined from transverse to sigmoid colon, the electromyograms exhibited 2 kinds of spike bursts: short spike bursts (SSB) localized at one electrode, and long spike bursts (LSB), isolated, propagated orally or aborally over a few centimeters, or aborally propagated over the whole length of the colon investigated (migrating long spike bursts, MLSB). Recordings were continuously performed over 24 hr. Each patient received at 7.00 p.m. on day 1 and at noon on day 2 an 800-1000 Kcal meal preceded by IV administration of pinaverium bromide (4 mg) or placebo. After placebo administration, the duration of LSB activity and the number of MLSB were significantly increased over 3 postprandial hr by comparison with the 2 hr preceding the meal. After pinaverium injection no significant postprandial change in LSB and MLSB activity was noted. The SSB activity was not modified after the meals preceded by placebo or pinaverium injection. These results suggest that the inhibitory action of pinaverium bromide on postprandial colonic motility may support the clinical efficacy of this agent in the treatment of the irritable bowel syndrome.