Motor function of gastric antrum and pylorus for evacuation of low and high viscosity meals in dogs.

In five conscious dogs motility of the antrum, pyloric sphincter, and duodenum was recorded with strain gauge transducers and induction coils. Gastric evacuation of low, medium, and high viscosity meals was measured via a duodenal cannula and observed simultaneously by radiography. Computer analysis of the propagation of the gastric waves revealed increased velocity in the distal antrum but no simultaneous contractions of the terminal antrum and pyloric sphincter. Radiography showed, and measurements of the antral diameter confirmed, that the indentations of the gastric waves were significantly deeper with the low viscosity liquid meal compared with the medium and high viscosity meals. Thereby, retropulsion of the medium and high viscosity ingesta was produced. Results indicated that gastric evacuation was regulated predominantly by the depth of the peristaltic indentation, which depended on the viscosity of the gastric contents. Nothing indicated that the phasic contractions of the pyloric sphincter were of importance for the regulation of gastric emptying.     

Postprandial Normal Saline Intake Delays Gastric Emptying of Solids in Conscious Dogs (Partial Involvement of CCK in Its Mechanism)

Although it is known that a caloric liquid mealgiven after food intake delays solid gastric emptying,the effect of a noncaloric liquid is not known. The aimsof this study were to determine the effect of normal saline given at 3 hr after feeding ongastric antral motor activity and gastric emptying andto evaluate the role of endogenous cholecystokinin inthe changes in gastric function induced by postprandial saline intake in conscious dogs. Two cannulaswere implanted in each of five mongrel dogs for infusionof phenolsulfonphthalein into the proximal duodenum andfor aspiration of luminal samples from the distal duodenum. Gastric contractile andemptying activity were measured by the force transducermethod and a freeze-drying method newly developed by ourgroup, respectively. Postprandial pancreaticobiliary secretion was assessed from amylase and bileacid outputs into the duodenum. One hundred grams offreeze-dried dog food was given as a solid meal aftermixing it with 100 ml of normal saline. The dogs were given 100 ml of normal saline per os at 3 hrafter feeding. In another study, intravenousadministration of devazepide, a specificcholecystokinin-A receptor antagonist, at a dose of 0.1mg/kg/hr was begun 15 min before postprandial saline intake andcontinued for 1 hr. Gastric antral motility wassignificantly (P < 0.01) inhibited for 30 min afterthe dogs had drunk saline at 3 hr after feeding. Themean fractional emptying rate of gastric solids inpercentage per 30 min after postprandial saline intakewas significantly (P < 0.05) slower than that in thecontrol study without saline intake at 3 hr after feeding. Amylase output into the duodenum afterpostprandial saline intake showed a gradual increaselasting for about 1 hr, whereas that of bile acidincreased transiently but markedly 15 min after saline intake, in comparison with the control study.Pretreatment with devazepide partially ameliorated thesuppression of gastric antral motility. Postprandialintake of saline inhibited gastric motor activity and delayed solid gastric emptying, whereas itincreased the outputs of amylase and bile acid.Endogenous cholecystokinin may be partially involved inthese phenomena caused by saline intake at 3 hr after feeding.     

Effects of nutrients on gastrointestinal motility and gastric emptying after Billroth-I gastrectomy in dogs

We wanted to clarify the way in which nutrients influence gastrointestinal motility and gastric emptying following distal gastrectomy with Billroth-I gastroduodenostomy. Four gastrectomized dogs were equipped with extraluminal strain gauge transducers. Gastric emptying was measured radiographically. Four intact dogs were used as controls for emptying studies. Following gastrectomy, gastric emptying of both acaloric and nutrient meals was rapid in the initial period of the experiments. Gastric outflow was supported by propagating duodenal contractions. Compared with control dogs, the early emptying of nutrient meals was accelerated. In the following period, nutrients markedly slowed gastric emptying compared with acaloric meals due to a segmenting contractile pattern of the duodenum and a significant diminution of gastrointestinal motility. Results suggest that after Billroth-I gastrectomy (1) the control of gastric emptying by nutrients acts too late to slow the initial enhanced gastric outflow, and (2) the duodenal contractile patterns influence gastric emptying.The study was supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/3-1.     

Erythromycin effects on gastric emptying, antral motility and plasma motilin and pancreatic polypeptide concentrations in anorexia nervosa.

In primary anorexia nervosa, gastric motility is often impaired and ensuing symptoms further discourage eating. Prokinetic agents have been shown to accelerate gastric emptying in affected patients. This study investigated whether emptying of a radiolabelled semisolid 1168 kJ meal and antral contractility were enhanced by intravenous erythromycin. Eight women and two men with anorexia nervosa (21-46 years, 50-75% of ideal body weight) received 200 mg erythromycin or placebo under crossover double blind conditions. Gastric emptying and antral contractility were recorded scintigraphically for 90 minutes. In addition, plasma motilin and pancreatic polypeptide concentrations were determined. With placebo, antral contractions were of regular 3 cycles/minute frequency. With erythromycin, less frequent and partly arrhythmic long duration contractions set in and emptying was accelerated: after 90 minutes, the activity remaining in the stomach was markedly less than with placebo in all patients (Sign test, p < 0.002). Basal motilin and pancreatic polypeptide concentrations were normal and showed a normal response to the meal in all patients. Motilin concentrations decreased slightly more and pancreatic polypeptide concentrations increased markedly more with erythromycin than with placebo, possibly because the meal reached the intestine earlier. In conclusion, erythromycin accelerated emptying markedly and in most patients induced an antral motor activity characterised by long duration contractions occurring at often irregular intervals.     

Cholinergic effects on human gastric motility

BACKGROUND: Cholinergic regulation of chronotropic (frequency) and inotropic (force) aspects of antral contractility and how these impact on gastric emptying are not well delineated. AIMS: To determine the effects of cholinergic stimulation and inhibition on myoelectric, contractile, and emptying parameters of gastric motility. METHODS: Ten normal subjects underwent three studies each, using simultaneous electrogastrography (EGG), antroduodenal manometry, and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of baseline fasting manometry and EGG, subjects received saline intravenously, atropine (0.6 mg then 0.25 mg/hour intravenously), or bethanechol (5 mg subcutaneously). This was followed by another 30 minutes' recording and by three hours of postprandial recording after ingestion of a technetium-99m labelled solid meal. RESULTS: During fasting, atropine decreased, whereas bethanechol increased, the antral manometric motility index and EGG power. Postprandially, atropine decreased the amplitude of antral contractions by DAS, decreased the postprandial antral manometric motility index, and slowed gastric emptying. Atropine caused a slight increase in postprandial frequency of antral contractions by DAS and gastric myoelectrical activity by EGG. Bethanechol slightly increased the amplitude, but slightly decreased the frequency of antral contractions by DAS and decreased the frequency of gastric myoelectrical activity by EGG, with no significant increase in the motility index or gastric emptying. CONCLUSIONS: Cholinergic antagonism with atropine reduces antral contractility and slows gastric emptying. Cholinergic stimulation with bethanechol increases antral contractility, but decreases the frequency of antral contractions, without altering the antral motility index or gastric emptying.     

Antroduodenal motor response to solid-liquid and homogenized meals.

The effect of the physical state of food on antroduodenal motor activity and the pattern of the emptying of an aqueous phase marker were examined in 6 healthy volunteers using an intestinal perfusion technique and intraluminal pressure transducers. Ingestion of a solid-liquid meal produced marked phasic changes in pressure in the distal antrum, lasting 92 +/- 10 min (mean +/- SE), while, in contrast, ingestion of the same nutrients in a homogenized state resulted in complete absence of distal antral changes in pressure lasting 133 +/- 12 min. The motor responses of the proximal antrum and duodenum were similar for the two meals. Both meals emptied during a 3-hr period, the pattern of emptying of the aqueous phase marker being similar for the two meals except for the first 40 min, when emptying was more rapid after the solid-liquid meal. The homogenized meal emptied despite the absence of changes in distal antral pressure. The gastrin response was similar for the two meals and is therefore not responsible for the different patterns of antral motility and gastric emptying.     

Gastric emptying after roux-y and billroth-I gastrectomy depends on viscosity of meal and contractile patterns of small intestine in dogs

The aim of the study was to examine gastrointestinal motility after distal gastrectomy and the influence of meal viscosity on gastric emptying. Gastrointestinal motility and gastric emptying of acaloric meals with different viscosities were measured in normal dogs and after a two-thirds gastrectomy with Billroth-I or Roux-Y gastroenterostomy. After distal gastrectomy, gastric emptying depended on the viscosity of the meal, as in normal dogs. Acaloric viscous meals emptied significantly faster in the Billroth-I than in the Roux-Y group due to different contractile patterns of the duodenum and jejunum. In comparison to normal dogs, gastric emptying of viscous meals was accelerated in the Billroth-I and delayed in the Roux-Y group. Several motility parameters of the stomach and intestine differed between the normal and gastrectomized dogs. Thus, after distal gastrectomy, the viscosity of the meal and the contractile patterns of the small intestine are important determinants of gastric emptying.Studies were supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/3-1.     

Anatomic, motor, and clinical assessment of vertical banded gastroplasty

The aim of this study was to assess gastric anatomy, motility, and emptying after vertical banded gastroplasty and to correlate the anatomic and physiologic results with clinical outcome. Eleven patients were studied at least 7 mo after operation, by which time they had lost 31% +/- 4% (mean +/- SEM) of their excess body weight. Stomal diameter, volume, and distensibility of the proximal gastric pouch were determined by a balloon distention technique. Gastric emptying was monitored scintigraphically both with and without distention of the proximal pouch. Stomal diameters ranged from 10 to 15 mm (mean +/- SEM = 11 +/- 1 mm), and pouch capacity ranged from 20 to 150 ml (76 +/- 9 ml). Mean intrapouch pressure was 13 mmHg before distention, increased to 22 mmHg with distention to half-maximal capacity, and then changed little with further distention to maximum capacity. Near maximal pouch distention during gastric emptying of a 300-ml test meal decreased antral contractile activity and speeded the initial rate of emptying (t25 with distention = 14 +/- 3 min vs. 24 +/- 3 min without distention, p less than 0.03), but did not alter the later rate of emptying. No clear-cut relationship was present between weight loss and stomal diameter, pouch volume, or gastric emptying. The conclusion was that distention of the proximal gastric pouch created by vertical banded gastroplasty inhibited antral contractions and increased the initial rate of gastric emptying, but no clear-cut correlation was found in this cohort between weight loss after the operation and stomal diameter, pouch size, and gastric emptying.     

Dynamic imaging of the stomach by real-time ultrasound--a method for the study of gastric motility.

The use of real-time ultrasonic imaging of the stomach for the study of gastric contractions in response to a liquid test meal is described. Gastric contractions in the pyloric antrum and distal body of the stomach were observed on closed circuit television, recorded on to cassette tape and also imaged on polaroid and ciné film. Gastric contractions were recorded from the pyloric antrum by longitudinal scanning in the lower epigastrium and reproducible motility tracings were obtained on a fibreoptic chart recorded. Intravenous metoclopramide enhanced the magnitude and frequency of antral movement, which was abolished by intravenous propantheline. Real-time ultrasonic imaging permits the non-invasive study of gastric contractions. It is safe, may be repeated as required, and provides a method for the study of the effect of drugs and disease states on gastric motility.     

Effects of oral cyclotropium bromide, hyoscine N-butylbromide and placebo on gastric emptying and antral motor activity in healthy man

Cyclotropium bromide, a new antimuscarinic agent, inhibits gastrointestinal motility in animals at lower doses than those required to inhibit gastric acid secretion and salivation. In man, cyclotropium bromide suppresses fasting and meal stimulated colonic motility. This study investigated the effects of single oral doses of 60 mg cyclotropium bromide, 60 mg hyoscine N-butylbromide and placebo on gastric emptying and on antral motor activity. Twenty four healthy men (mean age 25 years) participated in three experiments one week apart. The drugs were administered, in random double blind fashion, 30 minutes before the ingestion of a semisolid test meal labelled with 74 MBq (2 mCi) 99mTc sulphur colloid. A gamma camera coupled to a computer monitored gastric emptying together with amplitude, frequency, and propagation velocity of antral contractions. Cyclotropium bromide and, to a lesser degree, hyoscine N-butylbromide delayed gastric emptying and reduced contraction amplitude, but did not affect frequency and propagation velocity of antral contractions. Cyclotropium bromide was significantly more active than hyoscine N-butylbromide; the effects of hyoscine N-butylbromide differed significantly from placebo. Antral contractile activity was present all the time. After cyclotropium bromide, there was a significant correlation between antral contraction amplitude and gastric emptying. No adverse side effects occurred with any one treatment. In conclusion, cyclotropium bromide markedly inhibits gastric emptying and reduces antral contraction amplitude.     

Effects of nutrients on gastrointestinal motility and gastric emptying after distal gastrectomy with Roux-Y gastrojejunostomy in dogs

The aim of the study was to clarify whether nutrients are still capable of slowing gastric emptying following Roux-Y gastrectomy, as in normal dogs. Gastrointestinal motility and gastric emptying of acaloric and nutritive meals with different viscosities were measured in normal dogs and after a two-thirds Roux-Y gastrectomy. In gastrectomized dogs low-viscosity nutritive meals emptied unduly rapidly in an initial phase, although the frequency and spread of contractions, ie, the propulsive activity of the jejunal Roux limb were diminished. A slow emptying rate during the following period was due to a long-lasting inhibition of gastric and jejunal motility. Medium-viscosity nutritive meals emptied in gastrectomized dogs as slowly as in normal animals, but this effect was primarily caused by the meal viscosity and only secondarily by the nutrients. It is concluded that following Roux-Y gastrectomy a regulation of gastric emptying is preserved; however, the onset of an effective control is delayed, resulting in a rapid initial emptying of low-viscosity meals.Studies were supported by the Deutsche Forschungsgemeinschaft grant Eh 64/3-1.     

Quantitation of Duodenogastric Reflux and Antral Motility by Color Doppler Ultrasonography: Study in Healthy Volunteers and Patients with Gastric Ulcer

Fujimura J, Haruma K, Hata J, Yamanaka H, Sumii K, Kajiyama G. Quantitation of duodenogastric reflux and antral motility by color Doppler ultrasonography. Study in healthy volunteers and patients with gastric ulcer. Scand J Gastroenterol 1994;29:897-902.

Background: Our objective was to develop a simple, noninvasive method for evaluating duodenogastric reflux, along with antral motility and gastric emptying of a liquid meal. Methods: Antral motility and gastric emptying were measured by ordinary ultrasonography after a meal of 400 ml consommé. Duodenogastric reflux was evaluated by means of color Doppler. In a preliminary in vitro study we demonstrated that the test meal (consommé) contained oil particles suitable as a marker for color Doppler. We then investigated duodenogastric reflux, antral motility, and gastric emptying of a liquid meal in 43 asymptomatic healthy volunteers and in 24 patients with gastric ulcer. Results: This approach was feasible in 65 (97.0%) of the 67 subjects studied. Duodenogastric reflux was demonstrated in 26 (61.9%) of the 42 healthy volunteers and in 20 (87.0%) of the 23 patients with gastric ulcer. The frequency of the duodenogastric reflux and the reflux index were significantly increased in patients with gastric ulcer as compared with asymptomatic healthy volunteers. Gastric emptying and the motility index of antral contractions were significantly decreased in patients with gastric ulcer as compared with asymptomatic healthy volunteers. Conclusions: Ultrasonography with color Doppler is useful for evaluating abnormalities of gastroduodenal motility and can be used to understand the pathogenesis of such disorders.     

Effects of enhanced viscosity on canine gastric and intestinal motility

BACKGROUND AND AIM: The aim of this study was to investigate the effect of enhanced viscosity on gastric emptying and gastrointestinal motor and myoelectrical activities in dogs. METHOD: The study was performed in eight healthy female hound dogs chronically implanted with four pairs of gastric and two pairs of intestinal serosal electrodes and a duodenal fistula. Each dog was studied in three sessions and fed with three test meals with different viscosity. Gastric emptying was monitored for 2 h simultaneously with gastric and intestinal myoelectrical recordings. RESULTS: The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly delayed gastric emptying but had no effect on postprandial blood glucose levels in comparison with the meal containing no galactomannan. The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly increased the frequency and strength of intestinal motility but had no effect on intestinal slow wave rhythms. The product with enhanced viscosity had no effect on gastric motor activity or gastric slow waves. CONCLUSION: It was concluded that enhanced viscosity delays gastric emptying, increases postprandial intestinal but not gastric motility, and has no effects on gastric or intestinal slow waves.     

Gastric dysmotility after liquid bolus ingestion in systemic sclerosis: an ultrasonographic study

Gastric involvement appears quite commonly in systemic sclerosis (SSc). The aim of this study was to evaluate gastric wall motility using ultrasonography, a noninvasive method able to track both filling and emptying of fundus and antrum. The study was performed in 20 SSc patients and 20 healthy control subjects. Gastric filling and emptying were evaluated by transabdominal ultrasonography, measuring changes in fundus and antral areas over a 1-h period after ingestion of a liquid bolus (500 ml of mineral water). Areas of both gastric fundus and antrum at basal evaluation were found to be smaller in SSc patients than in healthy controls. Gastric filling was significantly reduced after ingestion of liquid bolus. Gastric emptying was delayed both in fundus and antrum. No significant differences of gastric wall motility have been observed in different subsets of SSc patients. Our findings show that gastric dysmotility is frequent and severe in SSc patients, contributing to the gastrointestinal disturbances which are very common in this disease.     

Relation between cholecystokinin and antral innervation in the control of gastric emptying in the rat.

BACKGROUND: Antral motility and the hormone cholecystokinin (CCK) are major determinants of the rate of gastric emptying. The relation between CCK and antral neurons in regulating gastric emptying is uncertain. Benzalkonium chloride (BAC) causes selective lesions in gut myenteric neurons after serosal application. AIM: To develop a model of antral denervation using BAC to enable the study of the relation between CCK and antral neurons in regulating gastric emptying. METHODS: BAC, vehicle or the afferent neurotoxin capsaicin were applied to the serosal surface of the rat antrum or corpus; neurochemical markers of intrinsic and afferent neurons were detected by using immunohistochemistry and radioimmunoassay. Gastric retention of solids was determined after fasting, and emptying of liquids was measured in rats with gastric fistulae. RESULTS: In BAC treated rats radioimmunoassay of tissue extracts revealed a dose related specific loss of gastrin releasing peptide, substance P, and vasoactive intestinal polypeptide immunoreactivities from the treated region, and immunohistochemistry revealed loss of the neuronal marker PGP 9.5 and the afferent neuropeptide calcitonin gene related peptide (CGRP). Adjacent untreated regions were unaffected by BAC, with the exception that CGRP was depleted in both corpus and antrum after antral treatment. After antral BAC treatment fasted rats retained solids for over 48 hours. Moreover, in antrally denervated rats with gastric fistulae, the emptying of saline, acid and peptone was delayed substantially. The CCK dependent inhibition of gastric emptying of peptone was preserved after antral treatment with BAC. CONCLUSIONS: Serosal BAC causes lesions in the innervation of the treated region of the stomach. The innervation of the antrum is essential for normal emptying of both liquids and solids, but the inhibition of gastric emptying produced by CCK is not dependent on antral neurons.     

Relationship of the motor activity of the antrum, pylorus, and duodenum to gastric emptying of a solid-liquid mixed meal

The postprandial motor activity of the antrum, pylorus, and duodenum in 15 healthy volunteers was compared with the profiles of emptying of the solid and liquid components of a meal. The liquid component of the meal emptied rapidly in an exponential manner, whereas the solid remained in the fundus of the stomach until approximately 80% of the liquid had emptied and then emptied in a linear manner. The onset of solid emptying was associated with an increase in the rate of occurrence of antral pressure waves (p less than 0.05), and the half-time for solid emptying (t1/2 - lag period) was inversely correlated (p less than 0.05) with the rate of coordinated contractions involving the antrum. The substitution of 25% dextrose in normal saline as the liquid component of the meal increased the half-time for liquid emptying from a median of 8 to 40 min (p less than 0.01), increased the lag period for solid emptying from 40 to 87 min (p less than 0.01), and increased the rate of occurrence of isolated pyloric pressure waves during the solid lag phase from 7 to 58/h (p less than 0.05), but did not affect the slope of solid emptying or the rate of coordinated contractions involving the antrum during the solid emptying period.     

The effect of stress on gastric emptying rate measured with a radionuclide tracer

BACKGROUND/AIMS: Stress can delay gastric emptying rate. This phenomenon has not yet been investigated with a physiological solid test meal or a regional analysis. METHODOLOGY: We investigated the gastric emptying rate in beagle dogs using a radio-labeled solid test meal and a gamma camera. The transport to an unknown environment served as a stress stimulus. This offers the advantage to mimic fairly well the clinical situation just before a diagnostic or therapeutic procedure. Control values were obtained after the third investigation, in which all dogs were accustomed to the environment. RESULTS: Regional analysis of the emptying curves from the whole gastric region revealed that the length of the lag phase increased with stress, but the post-initial emptying rate remained unchanged. Emptying of the fundus changed hardly, but the antropyloral motor activity decreased during stress. CONCLUSIONS: Gastric emptying rate is impeded during stress. It is necessary to limit the unnatural stress-stimuli, in order to mimic the clinical situation. Measurement techniques that influence directly gastric emptying or act as a stress-stimulus by themselves are undesirable. A radionuclide solid test meal is preferable and a regional analysis reveals the impairment of the antral motility as the mechanism of the delay of gastric emptying.     

Gastric motility and emptying in normal and post-vagotomy subjects.

The effects of proximal gastric vagotomy (PGV) and vagotomy with pyloroplasty (V and P) on gastric motility were studied using a solid meal labelled with a radiopharmaceutical agent. In having on-line computer facilities it was possible not only to record the rate of emptying but also to analyse the relative roles of the fundus and the antrum within the overall framework of gastric emptying. In normal subjects the fundus filled and then emptied in an almost linear pattern. The antrum, however, did not completely fill until well after the meal was eaten and thereafter appeared to maintain a constant volume during the study. The redistribution of contents between fundus and antrum was reflected in the total stomach emptying curve as a delay, or lag phase before gastric emptying commenced. After both types of vagotomy fundic filling was delayed, representing a slower eating time, which was presumably due to early satiety. Antral filling and volume was disturbed only after V and P, which was also reflected by a loss of the lag phase seen on the total stomach curve. PGV retained antral function but there was significant delay in the redistribution of contents between fundus and antrum, though this did not have clinical significance. The rate of emptying was unaffected by either operation. It was concluded PGV did maintain antral function and a more normal pattern of emptying compared with V and P. After V and P the changes in antral function were considerable and these changes are probably associated with some of the complications resulting from this operation.     

Gastric emptying after truncal vagotomy and pyloroplasty

We have studied the gastric (fundic and antral) emptying of solids and liquids by a radionuclide method in 20 patients after truncal vagotomy and pyloroplasty (TVP) and in 10 control subjects. Gastric emptying of solids in TVP patients was similar to that of the control group (NS), but fundic emptying did not show a lag phase and was significantly faster. A significantly higher percentage of the solid fraction of the test meal filled the antrum (32 +/- 16% versus 20 +/- 9%; p less than 0.05), and this quantity was constant during the study period. Gastric emptying of liquids was greatly hastened after surgery. In 22 min 50 +/- 16% had left the stomach (versus 40 +/- 14% in controls; p less than 0.001). At 90 min the amount of liquid remaining in the stomach was similar to that in the control subjects. TVP accelerates fundic emptying of solids, which are transferred to an overfilled, paretic antrum. Liquids are emptied by a bimodal pattern with a precipitous initial emptying followed by a second slower phase.     

Gastric motility measurement by MRI

The motor mechanisms associated with gastric emptying of nutrient liquids are unclear. Gastric emptying and motility were determined in seven healthy volunteers using an MRI technique following ingestion of 500 ml of (1) 10% and (2) 25% dextrose labeled with 1 mM Gd-DOTA. Emptying was determined with transaxial scans and motility during fast coronal scans 1.2 sec apart. Emptying was slower after ingestion of 25% dextrose. Following both meals, proximal gastric diameter remained relatively constant, while antral contractile frequency and depth varied markedly. These variations were greater after 10% dextrose. These studies suggest that antral motility changes contribute to slowing of gastric emptying by nutrient meals.