Gastric myoelectrical and antroduodenal motor activity in patients with achalasia

Achalasia is a primary motor disorder of the oesophagus, in which the myenteric plexus is involved. However, abnormalities in other parts of the digestive tract have also been described in achalasia. Whether gastric myoelectrical and duodenal motor activity in these patients is also affected is unknown. Therefore, interdigestive and postprandial gastric myoelectrical and antroduodenal motor activity were studied in 11 patients with achalasia, using electrogastrography (EGG) and stationary antroduodenal manometry.
Electrogastrographically, no differences were found in the gastric frequency, incidence of dysrhythmias and postprandial/fasting power ratio. In the interdigestive state a lower propagation velocity of phase III episodes was found in the achalasia patients, but other parameters were unaltered. Postprandially, no differences were found in the number of pressure waves, in the amplitude of pressure waves or in antro-duodenal coordination.
We conclude that gastric myoelectrical activity and antral motor activity in patients with achalasia is normal, suggesting an intact extrinsic and intrinsic neural innervation of the distal stomach. Although postprandial duodenal motility is normal, a lower propagation velocity of phase III suggests involvement of the small intestine in achalasia.     

Reproducibility of antroduodenal motility during prolonged ambulatory recording

Ambulatory recording of antroduodenal manometry is a novel technique with several advantages over standard stationary manometry recording. Although the feasibility of this technique in clinical practice has been demonstrated, reproducibility of antroduodenal motility recorded by means of ambulatory manometry has not been investigated. To test whether antroduodenal motility recorded by ambulatory manometry is reproducible, we performed two 24-h ambulatory antroduodenal manometry recordings in 18 healthy subjects according to an identical protocol with a 1-week interval. Motility was recorded with a five-channel solid-state catheter. Postprandial motility was recorded after consumption of two test meals and interdigestive motility was recorded nocturnally. Postprandial antroduodenal motor characteristics were identical between the separate recordings. The number and duration of nocturnal cycles of the interdigestive migrating motor complex were also in the same range. Phase III characteristics in general were not different between the two recordings. Only minor alterations were observed in the duration of phase III motor fronts with duodenal onset and in the number of interdigestive cycles concluded by duodenal onset phase III. Parameters obtained by qualitative analysis were comparable between the two recordings. The antroduodenal motility pattern, when measured by ambulatory recording with solid state catheters under standardized conditions, is very reproducible.     

Plasma Motilin Variation During the Interdigestive and Digestive States in Man

To evaluate the role of motilin in human physiology, we measured plasma motilin during the inter digestive and digestive states while recording antroduodenal contractile activity. In 24 healthy fasting subjects, 51 migrating periods of phase III activity were recognized, 42 of them started from the antral region and nine from the duodenum. A definite association was noted between circulating motilin and the gastric migrating motor complex. Significant peak elevations in plasma motilin were associated with phase Ills initiated from the antrum, but not with those originating from the duodenum. Exogenous synthetic motilin, when administered in supraphysiologic amounts, induced premature periods of front activity in fasting subjects. A test meal administered 30 minutes after a front of antral activity induced a significant release of motilin. Elevated plasma motilin levels were detected postprandially for a period of 30 minutes. Postprandial motilin increases were comparable in amplitude to the cyclic peak increases observed during the fasting period. Our study brings support for the argument that the contractile activity of the fasting stomach is regulated by circulating motilin in man, as it is in animals. The documented postprandial release of motilin is, however, unique to man and suggests that motilin could also be active during the digestive period in this species.     

Acute intraduodenal bile salt depletion leads to strong gallbladder contraction, altered antroduodenal motility and high plasma motilin levels in humans.

Cholecystokinin is the main hormone involved in postprandial gallbladder contraction. There is also considerable gallbladder contraction in the fasting state, associated with phase III of the gastrointestinal migrating motor complex and release of the hormone motilin. It has been proposed that intraduodenal bile salts exert a negative-feedback control on postprandial cholecystokinin release and resulting gallbladder contraction. We wanted to elucidate whether a similar control mechanism on gallbladder contraction exists in the fasting state. We therefore performed gallbladder ultrasonography and 24-h antroduodenal motility registrations and determined plasma cholecystokinin and motilin levels in six healthy subjects before and after acute (4 g) and chronic (8 days; 8 g day(-1)) oral cholestyramine. Acute cholestyramine strongly decreased gallbladder volumes and increased motilin without changed cholecystokinin levels. There was a negative relationship between gallbladder volumes and plasma motilin levels. Although there was a persistent fasting pattern of antroduodenal motility, its cycle length was increased (P < 0.03) with markedly longer phase II (P < 0. 005). Fasting gallbladder volumes 24 h later were still strongly decreased but gradually increased to pretreatment levels. Before and after 8 days cholestyramine, interdigestive and postprandial gallbladder emptying, intestinal migrating motor complex and hormone levels did not differ. We conclude that acute (but not chronic) intraduodenal bile salt depletion with cholestyramine affects gallbladder and antroduodenal motility, possibly partly related to motilin release.     

Phase III of the migrating motor complex: associated with endogenous xenin plasma peaks and induced by exogenous xenin

Xenin, a recently discovered peptide produced by specific endocrine cells of the duodenal mucosa, has shown exocrine, endocrine and motility effects in the gastroenteropancreatic system in animal experiments. The aim of the present investigation was to study the role of xenin in the regulation of duodenojejunal motility of humans. Twenty-nine healthy volunteers from the hospital staff gave informed consent to participate in this investigation. In 20 volunteers, we determined plasma concentrations of immunoreactive xenin at 15 min intervals over a mean time period of 8 h fasting and recorded the interdigestive motor activity of the duodenojejunum. In a double-blind randomized crossover study on other nine subjects, synthetic xenin in a dose of 4 pmol kg-1 min-1 or placebo was infused for 10 min intravenously in the interdigestive period and postprandially after a liquid meal. Duodenojejunal motility was recorded simultaneously. Predefined interdigestive xenin plasma peaks were found to be significantly associated with the phases III of the migrating motor complex. In the interdigestive period, xenin induced a premature phase III activity in each volunteer; this was followed by a second phase III in five out of nine subjects. In the postprandial state, xenin significantly increased contraction frequency and the percentage of aborally propagated contractions. These findings suggest a role of the peptide hormone xenin in modulating interdigestive and postprandial duodenojejunal motility in humans.     

Gastric Myoelectric Activity in Patients with Chronic Idiopathic Gastroparesis

Gastric myoelectric and manometric activities were studied by means of a peroral probe in six patients with chronic idiopathic gastroparesis characterized by a marked delay in gastric emptying at scintigraphy and by interdigestive gastric hypokinesia at manometry. Six normal subjects were examined as controls. The study was carried out by means of a probe with Ag-AgCl suction-needle electrodes and an open-tip manometric catheter. In normal subjects this method was able to record in the distal gastric antrum a regular occurrence of pacesetter potentials at a frequency of about three per minute associated with bursts of spikes or secondary waves in correspondence with the pressure waves. In patients with chronic idiopathic gastroparesis a large variety of electric arrhythmias ranging from premature control potentials to tachygastria, tachyarrhythmia, bradygastria, and bradyarrhythmia and to a complete disorganization of electric control activity were recorded. As no pressure waves were recorded during these myoelectric disturbances, the antral motor impairment that characterizes chronic idiopathic gastroparesis may be considered pathogenetically related to the absence of a regular occurrence of gastric control potentials.     

Postnatal Maturation of Small Intestinal Motility in Preterm and Term Infants

Perfusion manometry was used to study the maturation of small intestinal motility in 15 preterm and term infants before the initiation of enteral feeding (study 1); seven of the 11 preterm infants were restudied after 3 weeks or more of enteral feeding (study 2). During study 1, the interdigestive motility of the four term infants exhibited cycles of quiescence and rhythmic activity, compatible with migrating motor complexes observed regularly in adults; in response to feeding, motility changed to irregular, phasic activity. Preterm infants, however, showed only unorganized clusters of phasic activity during fasting, and there was no consistent pattern of motor response to feeding. After 3 or more weeks of enteral feeding, interdigestive cycles with migratory motor complexes and a consistent, obvious motor response to feeding were present. Preterm infants as young as 32 weeks' gestation showed "mature" motor patterns in study 2, results suggesting that intestinal motility matures with postconceptual age.     

Low antroduodenal pressure gradients are responsible for gastric emptying of a low-caloric liquid meal in humans

The motor mechanisms responsible for transpyloric flow of gastric contents are still poorly understood. The aim of our study was to investigate the relationship between luminal pressures and gastric wall motion and between gastroduodenal pressure gradients and pressure waves, and ante- and retro-grade transpyloric flow. In eight healthy volunteers, intraluminal pressures were recorded from the antrum and proximal duodenum. Transpyloric flow was monitored simultaneously using duplex ultrasonography, before, during and after ingestion of 300 mL meat soup. Transpyloric emptying occurred as sequences of alternating periods of emptying-reflux-emptying. Approximately one-third of the sequences were not associated with peristalsis. The antroduodenal pressure gradients were significantly lower during nonperistaltic-related emptying than during peristaltic-related emptying (0.15 (0-0.3) kPa, and 1.7 (0.2-2.0) kPa, respectively [mean plus minus (range)], P < 0.005). The duration of emptying episodes not associated with peristalsis were significantly longer than those associated with peristalsis at (6.5 (3-8.7) s and 4.4 (2-6) s, respectively, P=0.059). Manometry detected only 56% of the antral contractions seen on ultrasound. We concluded that gastric emptying of a low-calorie liquid meal occurs both during peristaltic and nonperistaltic antral activity. In spite of lower antroduodenal pressure gradients, the emptying episodes were longer for nonperistaltic emptying, which is likely to be caused by low pyloric resistance. Considerable flow seems to occur without peristalsis during gastric emptying of a low-calorie, liquid meal in humans.     

The Rectal Motor Complex

To identify patterns of motility in the rectum of humans during the day while awake and at night during sleep, and to correlate the patterns with interdigestive duodenal motor complexes and sleep cycles, intraluminal rectal pressure was recorded in 12 healthy subjects (five female, seven male; mean age, 28 years) using a flexible, noncompliant, silastic catheter and an Arndorfer system with a single perfused rectal port 6 cm above the anorectal junction, duodenal motility was recorded via a perfused oroduodenal tube, and sleep stages were determined electroencephalographically. Discrete bursts of rectal motor waves, called rectal motor complexes (RMCs), were identified on 72 occasions in 11 of the 12 subjects during 157 hours of recording. The RMCs were found in daytime during fasting or after feeding (0.2 ± 0.1 RMCs/hour), but were more easily and frequently identified at night during sleep (0.8 RMCs/hour, p < .01). The complexes had a distinct onset, a mean duration ± SEM of 9.5 ± 1.0 minutes, and a distinct decline. Within each complex, the waves had a mean frequency of 3.8 ± 0.3 per minute and a mean amplitude of 19 ± 2.7 mm Hg. Complex-to-complex intervals at night averaged 74 ± 15 minutes. No clear-cut temporal association was present between the complexes and phase III of interdigestive duodenal motor complex or the REM stage of sleep.     

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.     

Motor activity and affective illness. The relationship of amplitude and temporal distribution to changes in affective state

We measured motor activity with a self-contained monitoring device worn on the wrists of affectively ill patients and volunteer normal control subjects. Decreases in the daytime motor activity level were observed in depressed patients, compared with their improved (euthymic) or manic mood states. Moreover, affectively ill patients, even during euthymic periods, showed lower daytime motor activity levels than the control group housed in the same ward. These data provide objective evidence for decreases in motor activity that occur concomitantly with the depressive phase of illness in patients with affective disorder, and fluctuate in patients in euthymic or manic phases.     

Effect of 5-Hydroxytryptamine on Gastrointestinal Contractile Activity in Conscious Dogs

The effect of intravenous infusion of 5-hydroxytryptamine (5-HT) on gastrointestinal contractile activity was studied in conscious dogs during the digestive and interdigestive states. It was found that 30 to 300 μg/kg per hour of 5-HT induced phasic contractions mainly in the gastric antrum, duodenum, jejunum, and mid-intestine. However, when doses greater than 100 μg/kg per hour were used, a stimulatory effect was seen in the ileum and colon. The dose-dependent stimulatory effect of 5-HT on gastrointestinal motor activity was observed in both the frequency and amplitude of contractions. Atropine-resistant 5-HT-induced contractions in the stomach were completely inhibited by methysergide. This fact strongly suggests the existence of 5-HT receptor on the smooth muscle. The stimulatory effect of 5-HT given intravenously quickly disappeared with the cessation of infusion. No significant side effects such as nausea, vomiting, diarrhea, or other symptoms suggesting abdominal pain were observed during or after the intravenous infusion of 5-HT in doses between 10 and 300 μg/kg per hour in any of the dogs.     

Distinctive motor responses to human acute salmonellosis in the jejunum and ileum

Given the differences that normally exist in jejunal and Heal motility patterns, we wished to determine whether these regions respond differently to acute enteric infections. In 10 patients with acute gastroenteritis induced by Salmonella infection and 12 healthy individuals jejunal and Heal motility was recorded at eight equidistant sites by a manometric system for 6 h during fasting. All were healthy individuals, but only three of 10 patients exhibited the cyclic inter digestive motor complex; 82 ± 9 min duration in healthy individuals (mean ± SE). In the jejenum, patients exhibited short bursts of intense activity (6.3 ± 1.6 bursts/subject in patients vs. 1.8 ± 0.5 in controls; P < 0.05); burst activity was scarce in the ileum. In contrast to healthy subjects, patients exhibited prolonged periods (64 ± 3 min duration) of Heal motor quiescence, that accounted for 32 ± 11% of recording time; such silent periods were not observed in the jejunum. Prolonged propagated ileal contractions were observed only in two healthy subjects, but in seven out of 10 patients. These data indicate that acute Salmonella infection magnifies the motor differences between the jejunum and the ileum; both regions generate aberrant and markedly different dysmotility patterns.     

Effect of motilin and erythromycin on the motor activity of the human colon

Motilin and motilin receptor agonist erythromycin were administered to healthy subjects where colonic motility was recorded manometrically from the hepatic flexure to the rectum. Experiments were carried out during the fasting basal state or when colonic motility was stimulated by the ingestion of a 1000 kcal lunch. A supraphysiological dose of motilin (100 ng kg^?1, i.v.) increased the motor activity of the fasting sigmoid colon, but the response was smaller than the meal induced activity. The administration of erythromycin (200 mg, i.v.) during the inter digestive period induced, on the sigmoid region, a motor response that was not significantly different in amplitude from the post-prandial contractile profile. However, on the more proximal segments of the colon, motilin and erythromycin were inactive. When both agents were administered during the digestive period, both failed to modify the contractile stimulation normally seen in all regions of the colon after a meal. Therefore the colonic motor response obtained with stimulation of motilin receptors in man appears limited;it is restricted to the sigmoid, it can be seen only during fasting and it is of weak amplitude.     

Adrenergic Control of Interdigestive and Digestive Motility via the Pyloric Region

This study examines the influence of an α-adrenergic blocking drug, phentolamine, on inter digestive and digestive motility when given intraarterially, close to the pylorus. In seven mongrel dogs four extraluminal bipolar platinum electrodes and four strain-gauge force transducers were placed at the antrum and proximal duodenum and three mini strain gauges and one electrode at the pyloric ring. After two migrating motor complexes (MMCs) were registered the drug was applied through a catheter inserted via the arteria gastroomentalis dextra to the pylorus, during phase I, the middle and end of phase II of the MMC, and 15 to 25 minutes after a meat meal. Local α-adrenergic blockade of the pylorus caused immediate conversion of phase I to phase II of the MMC, with significant prolongation of phase II, broadening of antral and pyloric contractions, and in some animals giant contractions with vomiting and retching. The pyloric motility index in phase III increased up to 22%. It prolonged phase II by 237%. Phentolamine after the meat meal caused an increase in motility index, mainly in the pylorus, while the increase in contraction frequency was less pronounced. The results indicate inhibitory adrenergic control of the interdigestive motor pattern and digestive motility in the pyloric region.     

Effects of time and tasks upon auditory and somatosensory evoked potentials in man.

Auditory evoked potentials (AEPs) recorded from the vertex and somatosensory evoked potentials (SEPs) recorded from the somatosensory and motor areas and vertex were examined during visual and auditory discrimination tasks, with and without motor responses, and during motor tasks alone in normal human subjects. These procedures allowed the separation of sensory discrimination from motor activity effects on the evoked potentials. It was observed that EPs were modified systematically by task and by temporal variables, even though vigilance, as evaluated through EEG recording and performance level, was stable throughout the experimental recording session. 1. AEPs were minimally influenced by time, but very sensitive to task. Inversely, the SEP amplitude decreased considerably with time and less with task. There was evidence of time/task interaction. 2. The magnitude of SEP attenuation in time was reduced by intervening rest periods. 3. The sensory modality in which the discrimination task was performed did not influence the effect on EPs. A discrimination task involving a motor response reduced EPs more than a pure discrimination or a pure motor task. The task effect seems to involve a general, mechanism (load imposed upon the subject) not dependent on the particular sensory channel used to deliver task-relevant information.     

Difficulty in estimating localized bowel contraction by colonic manometry: a simultaneous recording of intraluminal pressure and luminal calibre

To examine whether or not intraluminal pressure changes at a site in the human colon reflect with fidelity the local bowel wall contractions or relaxation, endoscopic recording of the changes in colonic calibre as a parameter of the motor events with simultaneous manometry was performed at a fixed site in a prepared sigmoid colon during the interdigestive state. In four of the 12 subjects, a total of 20 phasic pressure waves with an amplitude of 13–22 mmHg and a duration of 13–18 sec were obtained in a 20 min recording session. Eighteen of the 20 phasic pressure waves (90%) were associated not with a decrease (contraction) but with an increase in the calibre (relaxation). The pressure change began 0.2–8.4 sec (mean: 4.5 sec) behind and ended ? 1.8 to 8 sec (mean: 3.5 sec) ahead of the calibre change. In the other eight subjects, no phasic pressure change was recorded in the presence of an overt calibre change. We conclude that manometric phasic pressure change recorded at a site in the empty human colon is not necessarily correlated with the localized contractile activity. Extrapolation of pressure profiles in the colon to motor events at the manometric site should be cautious.     

Anticholinesterase Activity of Histamine H2-Receptor Antagonists in the Dog: Their Possible Role in Gastric Motor Activity

We studied the anticholinesterase activity of three H₂-receptor antagonists (cimetidine, ranitidine, and famotidine) in vitro and in conscious dogs with chronically implanted strain-gauge force transducers. In vivo, acetylcholine (ACh) was infused intravenously at a dose of 0.05 mg/(kg · min) for 5 minutes with or without a background continuous intravenous infusion of H₂-receptor antagonists or neostigmine during the quiescent period of the interdigestive state. Cimetidine and ranitidine enhanced the ACh-induced contractions in a dose-dependent manner in the gastric antrum, whereas famotidine did not. In vitro, the median inhibitory concentration (IC₅₀) of the acetyl-cholinesterase activity of ranitidine was 3.5 × 10⁻⁶ M, and that of cimetidine 2.5 × 10⁻⁴ M, whereas famotidine had no effect on cholinesterase activity even at concentrations up to 10⁻³ M. The effects of a bolus intravenous injection of the three H₂-receptor antagonists on gastric motor activity also were examined in the digestive state. Cimetidine at 10.0 mg/kg and ranitidine at 3.0 mg/kg significantly increased gastric motor activity. This dose of ranitidine, however, sometimes caused the dogs to collapse and significantly decreased blood pressure in the anesthetized dogs. In conclusion, the H₂-receptor antagonists cimetidine and ranitidine enhanced gastric motor activity through the mechanism of their anticholinesterase activity, but further studies on gastric emptying and the circulatory system are needed.     

Axonal refractory period of single short toe extensor motor units in neuropathies and neuromuscular diseases.

Electromyographic recordings were carried out on 36 patients with neuropathies and neuromuscular disorders with a selectivity permitting identification of single motor unit potentials during maximal voluntary effort and after supramaximal nerve stimulation. The axonal conduction velocity and refractory period of 117 motor units were determined and the findings were compared to those in previously studied normal subjects. The axonal conduction velocity spectrum was 15-52 m/s. Fifteen per cent of all motor units had axonal conduction velocities below 30 m/s which is below the normal range. When test stimulus strength was 10% above the axonal threshold at rest the refractory period was 1.88 +/- 0.43 ms which is slightly longer than the corresponding value in healthy subjects (1.67 +/- 0.25 ms). The relationship between the axonal conduction velocity and refractory period observed in healthy subjects did not hold for these patients. Thirty-eight per cent of all motor motor units with axonal conduction velocities within the normal range had refractory periods longer than 2.0 ms which was only infrequently observed in healthy subjects. When test stimulus strength was 50% above the axonal threshold at rest the refractory period was 1.16 +/- 0.42 ms which was significantly longer (p less than 0.02) than in healthy subjects (0.64 +/- 0.21 ms). At this stimulus strength 40% of all motor units with axonal conduction velocities within the normal range had refractory periods above 1.0 ms which was never the case in healthy subjects. The significance of these findings with regard to the clinical application of the Hopf technique for determining the conduction velocity spectrum of peripheral motor nerves is discussed.     

Electrogastroenterographic study of the digestive motor effects of prolonged psychotropic treatment]

Functional digestive complaints are frequent in psychiatri patients: simple constipation, which cannot be explained solely by the loss of the sensation of rectal fullness; occlusions, occasionally hemorragies; the late complication of dolichomegacolon (Bourgeois, 1973). In 160 subjects, an attempt to understand the physio-pathology were made by recording diurnal digestive motor activity using skin electrodes placed on the abdomen and extremities (electrogastroenterography or E.G.E.G.). A hypoactive E.G.E.G. was observed in 2/3 of 18 psychotic depressive patients, in 3/4 of 36 schizophrenies. The nocive effect of giving sedative phenothiazine and antiparkinsonian drugs (trihexyphenidyl or ethybenzatropine) during long periods is clear. Whereas non sedative phenothiazine and clotiapine gicen in small doses, do not have an undesirable effect. Sulpiride has been used in gastroduodenal dyskinesia. The dyskinesia noted by the E.G.E.G., sometimes found in the large intestin, were found in 55% of 30 patients with caracter disorders; they coincide with the high frequency of electro-encephalogram dysrythmies. Finally, in hysterical patients, one usually observes normal E.G.E.G., tracings which confirms the clinical observation that hysterical and psychosomatic symptoms, may succeed each other, but do not appear at the same time. In the same categories of patients, no longer treated in a classical psychiatric environment but in a group with institutional objectives, the same clinic results were obtained with fewer digestive disturbances. This tends to show the inutility and nocivity of excessive doses of psychotropic drugs given alone or in complexe association.