Chemospecific alterations in duodenal perception and motor response in functional dyspepsia

OBJECTIVE: Abnormal gastroduodenal motility and visceral hypersensitivity to intraduodenal acid have recently been recognized as pathophysiological factors in functional dyspepsia. The aim of this study was to assess whether these abnormalities in functional dyspepsia depend on the chemical composition of the stimulus. METHODS: In 17 patients with functional dyspepsia and 10 healthy controls 20-channel antropyloroduodenal manometry was performed. During phase II of the migrating motor complex small volumes (5 ml) of saline, acid, lipids, and dextrose were administered intraduodenally. Motility parameters and sensation scores for nausea, fullness, and epigastric pain were compared before and after each infusion and among the two groups. RESULTS: Acid induced a duodenal motor response in both groups, but less pressure waves (p < 0.05) and antegrade propagated pressure waves (p < 0.05) were observed in patients than in controls. In both groups lipids induced a similar, prominent increase in duodenal pressure waves. Acid and lipids suppressed antral-propagated pressure waves in both groups. Dextrose induced a modest increase in duodenal-propagated pressure waves in patients (p < 0.05) but not in controls. Although all infusions induced a mild increase in nausea in patients, only acid induced a significant increase in nausea after 1 min (p < 0.01). None of the infusions affected the sensations of epigastric pain or fullness in patients, nor did any infusions induce sensations in controls. CONCLUSIONS: In functional dyspepsia alterations in sensor and motor responses to intraduodenal acid and nutrients are chemospecific, suggesting an abnormality at the level of visceral afferents or mucosal chemoreceptors in these patients.     

Intravenous erythromycin overcomes small intestinal feedback on antral, pyloric, and duodenal motility.

The retardation of gastric emptying caused by intraduodenal lipid is associated with suppression of antral contractions and stimulation of localized pyloric contractions. Similar patterns of motility have been described in patients with gastroparesis. The effect of erythromycin on the antropyloroduodenal motor responses to intraduodenal lipid was investigated. In 17 volunteers an intraduodenal lipid infusion (10% Intralipid) was given at 1 mL/min for 50 minutes. Either erythromycin (3 mg/kg) or saline was administered IV for 15 minutes, beginning 20 minutes after the start of the intraduodenal lipid infusion. Antral, pyloric, and duodenal motility were measured with a sleeve/sidehole manometric assembly. Intraduodenal lipid stimulated localized pyloric contractions. Erythromycin suppressed localized phasic (P less than 0.003) and tonic (P less than 0.002) pyloric pressure waves and stimulated antral (P less than 0.003) and duodenal pressure waves (P less than 0.02). After erythromycin antral pressure waves were usually of high amplitude (greater than 50 mm Hg) and often associated with duodenal pressure waves. It was concluded that erythromycin overcomes the effects of intraduodenal lipid on antral, pyloric, and duodenal motility. These effects probably contribute to the gastrokinetic properties of erythromycin.     

Small intestinal glucose absorption and duodenal motility in type 1 diabetes mellitus

OBJECTIVE: Small intestinal glucose absorption is increased in animal models of diabetes mellitus, but little data are available in humans. Small intestinal motility is reported to be frequently abnormal in patients with diabetes and could potentially affect glucose absorption. Our aim was to evaluate small intestinal glucose absorption and duodenal motor responses to intraduodenal nutrients, in patients with type 1 diabetes and controls. METHODS: Eight type 1 patients (two with autonomic neuropathy) and nine controls were studied during euglycemia. A manometric catheter was positioned across the pylorus, and nutrient infused intraduodenally (90 kcal over 30 min), followed by a bolus of 3-O-methylglucose (3-OMG). Blood was sampled to measure glucose and 3-OMG concentrations. RESULTS: During nutrient infusion, the number of duodenal waves did not differ between patients and controls. After the infusion, patients with diabetes had more propagated duodenal wave sequences (p < 0.05). The area under the plasma 3-OMG curve did not differ between the groups but correlated with both the blood glucose concentration at the time of 3-OMG administration (r = 0.64, p < 0.005) and the number of duodenal waves (r = 0.52, p < 0.05) and antegrade propagated duodenal sequences (r = 0.51, p < 0.05) preceding the 3-OMG bolus. CONCLUSIONS: During euglycemia, duodenal motor responses to small intestinal nutrient are comparable in patients with relatively uncomplicated type 1 diabetes and healthy subjects, but duodenal motility after nutrient infusion is increased in patients. Small intestinal glucose absorption is similar in patients and controls, but may be dependent on the blood glucose concentration and duodenal motor activity.     

A pilot study on chemospecific duodenal visceral sensitivity in inflammatory bowel disease in remission

BACKGROUND: Patients with inflammatory bowel disease (IBD) in remission frequently experience symptoms resembling irritable bowel syndrome (IBS). In IBS altered motility and visceral sensitivity are found throughout the whole gastrointestinal tract. We aimed to study chemospecific antroduodenal sensitivity in IBD patients. METHODS: Antroduodenal manometry was performed in 10 IBD patients in remission and 13 controls. Small volumes of nutrients and acid were administered intraduodenally. Motility variables and sensation scores were compared before and after each infusion. RESULTS: Acid and lipid infusion decreased the number of antral pressure waves in both groups (p < 0.05). After acid infusion the number of duodenal pressure waves in the sideholes just distal to the infusion port increased in IBD patients compared to the controls (p < 0.05). Lipid infusion increased the number of duodenal propagated pressure waves in both groups, but in controls they were also increased over longer distances (p < 0.005). None of the infusions significantly affected the sensation scores. CONCLUSION: Subtle alterations in chemospecific responses to lipids and acid in IBD patients in remission were observed, affecting duodenal motor activity but not duodenal perception. These changes are indicative of changes at the chemoreceptor level in the duodenal wall in this patient group.     

The stimulation of antral motility by erythromycin is attenuated by hyperglycemia

OBJECTIVE: Diabetic gastroparesis is usually treated with prokinetic drugs, of which the most potent, when given intravenously during euglycemia, is erythromycin. Recent studies have demonstrated that the gastrokinetic effects of erythromycin are attenuated by hyperglycemia. The aim of this study was to determine whether the effects of erythromycin on antropyloroduodenal motility, including the organization of antral pressure waves, are modified by hyperglycemia. METHODS: A total of eight healthy male volunteers (median age 24 yr) were studied on 2 days each in randomized order. A manometric assembly, incorporating six antral, two pyloric, and seven duodenal sideholes and a pyloric sleeve sensor, was positioned with the sleeve spanning the pylorus. The blood glucose concentration was stabilized at about 5 mmol/L (euglycemia) or 15 mmol/L (hyperglycemia). After 30 min (T = 0), an intraduodenal lipid infusion (1.5 kcal/min) was commenced and continued until the end of the study. At T = 20 minutes, erythromycin (200 mg) as the lactobionate was infused intravenously over 20 min, followed by 100 mg over the next 40 min. RESULTS: Intravenous erythromycin increased the amplitude of antral waves during intraduodenal lipid infusion at both blood glucose concentrations (p < 0.01 for euglycemia and p < 0.05 for hyperglycemia). After erythromycin (T = 20 to T = 80), the frequency (p < 0.05) and amplitude (p < 0.01) of antral waves were less during hyperglycemia than euglycemia. Both propagated (p < 0.0005) and nonpropagated (p < 0.01) antral waves were decreased by hyperglycemia, but the suppression of propagated waves was greater (p < 0.05). Erythromycin reduced the frequency (p = 0.09) but increased the amplitude (p < 0.05) of phasic pyloric pressures, and decreased basal pyloric pressure (p < 0.0005). The frequency (p = 0.06) and amplitude (p < 0.05) of phasic pyloric waves during erythromycin infusion were slightly less during hyperglycemia than euglycemia, whereas there was no effect of the blood glucose concentration on basal pyloric pressure. Erythromycin increased the amplitude (p < 0.001) but not the frequency of duodenal waves; the frequency and amplitude of duodenal waves did not differ between the two blood glucose concentrations. CONCLUSIONS: Hyperglycemia attenuates the stimulation of antral pressures and propagated antral sequences by erythromycin, but not the effects of erythromycin on pyloric or duodenal motility.     

Effects of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on antropyloroduodenal motility and appetite in response to intraduodenal lipid infusion in humans

BACKGROUND: Studies in animals indicate that endogenous nitric oxide (NO) is an important inhibitory neurotransmitter in the gastrointestinal tract and that it modulates food intake. We evaluate the role of NO mechanisms in mediating the effects of small intestinal nutrients on antropyloroduodenal motility and appetite in humans. METHODS: On 2 separate days, 8 healthy adult men received intravenous L-NAME 180 microg/kg/h or 0.9% saline (0-150 min); between 30 min and 120 min, an intraduodenal lipid infusion (2 kcal/min) was administered, and at 120 min subjects were offered a buffet meal (120-150 min). Antropyloroduodenal pressures were measured with a sleeve/sidehole manometric assembly. During the infusions, perceptions of hunger and fullness were assessed with visual analog questionnaires and amount and macronutrient content of food consumed at the buffet meal were quantified. Blood pressure and heart rate were monitored at regular intervals. RESULTS: Intraduodenal lipid infusion was associated with increases in fullness (P < 0.05) and in frequency of isolated pyloric pressure waves (P < 0.05) and basal pyloric pressure (P < 0.05); and decreases in hunger (P < 0.05) and in frequency of antral (P < 0.05) and duodenal (P < 0.05) pressure waves. L-NAME increased diastolic blood pressure (P = 0.08) and decreased heart rate (P < 0.05), but had no effect on antropyloroduodenal pressures or food intake. CONCLUSIONS: Intravenous administration of the systemic NO synthase inhibitor, L-NAME, in a dose that affects cardiovascular function in healthy humans does not modify the antropyloroduodenal motor and appetite responses to intraduodenal lipid infusion.     

Disturbed gastroduodenal motility in patients with active and healed duodenal ulceration

Disordered gastroduodenal motility may promote duodenal ulceration by allowing prolonged acid contact with the duodenal mucosa. Using a multilumen perfused catheter incorporating 3 pH microelectrodes, antral and duodenal pH and antropyloroduodenal pressure activity were recorded in 36 subjects (10 with healed duodenal ulceration, 11 with active duodenal ulceration, and 15 healthy volunteers) during fasting and after a radiolabeled solid test meal. Correct pH probe/catheter position was continuously verified by recording transmucosal potential difference across the pylorus. Patients with active and healed duodenal ulcer had similarly disordered gastroduodenal motility. The chief abnormalities consisted of an increase in postprandial duodenal retroperistalsis (healed duodenal ulceration, 12 +/- 1 events per hour; active duodenal ulceration, 12 +/- 1; control, 6 +/- 1; mean +/- SEM: healed and active duodenal ulceration vs. control, P = 0.004 and P = 0.03, respectively), a reduction in pressure waves sweeping aborally through the duodenum after the meal (healed duodenal ulceration, 22 +/- 4 events per hour; active duodenal ulceration, 23 +/- 3; control, 34 +/- 4: healed and active duodenal ulceration vs. control, P = 0.04 and P less than 0.05, respectively), and an increased incidence of atypical, complex forms of coordinated duodenal motor activity throughout the study (postprandial data; healed duodenal ulceration, 8 +/- 1 events per hour; active duodenal ulceration, 10 +/- 1; control, 4 +/- 1: healed and active duodenal ulceration vs. control, P = 0.02 and P less than 0.02, respectively). In addition, gastric emptying of the solid test meal was significantly delayed in healed, but not active, duodenal ulceration [half-emptying time, healed duodenal ulceration 185 minutes (117-235); active duodenal ulceration 102 minutes (80-200); control 107 minutes (78-130): healed duodenal ulceration vs. control, P less than 0.009]. Duodenal bulb pH was similar in controls and patients with active duodenal ulceration; however, bulb pH was less than 4 for a significantly greater period of time in healed duodenal ulceration compared with active ulcer patients, particularly after the meal. In conclusion, duodenal ulcer disease is associated with disturbed gastroduodenal motility, even when the ulcer is quiescent and when intraduodenal acidity is low. In healed duodenal ulceration, disturbed motility may promote ulcer relapse by impairing acid clearance from the bulb. However, in active ulceration other factors such as mucosal bicarbonate secretion may have a more influential role in determining intraduodenal pH.     

Characteristics of postprandial duodenal motor patterns in dogs

In this study special attention was paid to the characteristics of duodenal motility under the influence of various test meals. Closely spaced strain gauge transducers and a computerized method were used to analyze motor patterns of the duodenum and the adjacent jejunum. Compared with an acaloric meal, nutrients shortened the length of contraction spread in the duodenum from 5.2±1.0 to 3.8±0.5–2.8±0.6 cm and in the jejunum from 10.5±3.0 to 7.4±1.3–5.2±0.8 cm. Additionally, contraction frequency was reduced. Basic differences were found between duodenal and jejunal motility. They were most marked in absence of nutrients. The duodenal motor pattern was characterized by a lower contraction frequency (8.0±2.2 vs 11.1±1.8/min), a shorter length of contraction spread (5.2±1.0 vs 10.5±3.0 cm), and a higher incidence of stationary contractions (50% vs 34%). On the duodenal bulb 72% of contractions represented contraction waves, whereas in the mid-duodenum the predominant feature was stationary contractions (57%) promoting the mixing of chyme with secretions. The characteristic duodenal motor patterns might be related to special functions of the duodenum for transport and digestion.The study was supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/2.     

Effects of a meal and bisacodyl on colonic motility in healthy volunteers and patients with slow-transit constipation

In the present study, the gastrocolonic response after ingestion of a standardized liquid meal and the response to a local chemical stimulus were investigated in 10 healthy volunteers and 10 patients with slow-transit constipation (as determined by marker studies). Colonic pressures were recorded while fasting, after ingestion of a standardized meal and after intracolonic bisacodyl infusion, using a 12-channel water-perfused catheter. Pressure waves propagating over at least 20 cm (HAPPW) were identified visually and automated analysis was carried out on remaining segmental motility. Increases of motility after a meal and bisacodyl were seen in healthy subjects, whereas patients did not show these responses. The time until occurrence of the first HAPPW after bisacodyl infusion tended to be prolonged (4.3 ± 1.4 vs 36.1 ± 15.3; P = 0.053) and the number of HAPPWs in the first 30 min. after infusion was lower compared to healthy subjects (2.1 ± 0.2 vs 5.4 ± 0.3; P < 0.01). The percentage of HAPPWs that were experienced as urge or cramp was significantly lower in constipated patients (53 ± 3% vs 95 ± 1%; P < 0.005). In conclusion, this study shows that in patients with slow-transit constipation, the colonic motor response to a meal and to bisacodyl, as well as the perception of bisacodyl-induced propagated pressure waves is decreased.     

Adaptive changes in the pyloric motor response to intraduodenal dextrose in normal subjects.

Gastric emptying of glucose is faster after dietary supplementation of glucose, suggesting specific adaptation to changes in nutrient intake. In the present study, the effects of a continuous long-term (0-120-minute) and two short-term (0-20- and 80-100-minute) intraduodenal infusions of dextrose (2.4 kcal/min) on antropyloroduodenal motility and blood glucose, plasma gastric inhibitory polypeptide, and insulin concentrations were evaluated in nine volunteers. In four volunteers, an intraduodenal infusion of triglyceride (2.4 kcal/min) was administered immediately after the long-term dextrose infusion. The long-term dextrose infusion initially increased isolated pyloric pressure waves (IPPWs) and basal pyloric pressure (P < 0.05 for both), but after about 30 minutes IPPWs and basal pyloric pressure decreased and returned to baseline within 80 minutes. Each short-term infusion increased IPPWs and basal pyloric pressure (P < 0.05 for both). Antral pressure waves remained suppressed during the long-term dextrose infusion. Intraduodenal triglyceride increased IPPWs and basal pyloric pressure (P < 0.05 for both). The long-term dextrose infusion was associated with a sustained increase, and both short-term dextrose infusions were associated with peaks in glucose, insulin, and gastric inhibitory polypeptide levels. There was no significant relationship between biochemical measurements and antropyloroduodenal motility. It is concluded that specific adaptive changes occur rapidly in the phasic and tonic pyloric motor response, but not the antral motor response, to intraduodenal dextrose.     

The effect of naloxone on lipid-induced pyloric motor response in humans

This study examines whether opioid receptors are involved in the mediation of the pyloric motor response to intraduodenal lipid infusion. Antral, pyloric, and duodenal manometry was performed in seven healthy volunteers with a sleeve/multiple side-hole manometric assembly. Triglyceride emulsion and normal saline were infused alternately into the duodenum through the manometric assembly for two 30-minute periods each. Naloxone was then administered as an IV bolus, 40 micrograms/kg, followed by an infusion of 60 micrograms.kg-1.h-1 that was continued during testing of the duodenal infusates. Before naloxone administration, intraduodenal lipid produced significant increases in the rate of isolated pyloric pressure waves and basal pyloric tone when compared with saline (P = 0.009 and 0.027, respectively). The pyloric motor responses were unchanged after administration of naloxone, indicating that in humans, naloxone-sensitive opioid mechanisms are not involved in the mediation of lipid-induced pyloric motor responses.     

The effect of acute hyperglycaemia on small intestinal motility in normal subjects

Summary The effects of hyperglycaemia on postprandial small intestinal motor activity are unclear. Duodenal and jejunal pressures and duodeno-caecal transit were measured in eight healthy male volunteers during euglycaemia (blood glucose 4–6 mmol/l) and hyperglycaemia (blood glucose 12–15 mmol/l). Duodenal and jejunal pressures were recorded with a manometric assembly during intraduodenal infusion of 100 ml nutrient liquid comprising 14% protein, 31.5% fat and 54.5% carbohydrate together with 15 g lactulose. Duodeno-caecal transit was determined by a breath hydrogen technique. The number of duodenal (p<0.05) and jejunal (p<0.01) pressure waves, excluding phase III episodes was reduced during hyperglycaemia compared to euglycaemia. Hyperglycaemia was associated with earlier onset of phase III activity (30±12 vs 132±20 min; p<0.05). Duodeno-caecal transit was slower during hyperglycaemia when compared to euglycaemia (114±17 vs 49±6 min, p<0.01). We conclude that induced hyperglycaemia has major effects on postprandial small intestinal motility. The reduction in duodenal and jejunal motor activity is likely to explain the retardation of small intestinal transit during hyperglycaemia.Abbreviations TMPD Transmusocal potential difference - MMC migrating myoelectric complex     

Canine small bowel motor activity in response to intraduodenal infusion of nutrient mixtures of increasing caloric load in dogs

The effect of nutrients on small intestinal motility is controversial. Our aim was to analyze the effect of intraduodenal infusion of mixtures of nutrients of increasing caloric load, on intestinal motility. Studies were performed in dogs with a duodenal cannula. Isosmolar infusions of saline, 0.5, 2, and 4 kcal/min were performed and motility recorded by means of infused catheters. Nonstatistically significant differences were observed between frequency of contractions during infusion of 0.5 (4.1 ± 1.6 cpm) and 2 kcal/min (5.3 ± 1.5 cpm) compared to control (4.3 ± 1.9 cpm). With 4 kcal/min a significant decrease of frequency (2.7 ± 0.9 cpm) was observed. A similar finding was observed for amplitude of contrations. With 0.5 kcal/min fasting cyclic activity was still present, but the numbers of phase III were significantly reduced, associated with an increased duration of phase II. With higher caloric loads cyclic fasting activity was replaced by marked variations of frequency, following a cyclic pattern. A lower threshold for mechanisms switching the fasting to fed state was observed, compared to those controlling frequency and amplitude.     

Effects of Ondansetron on Gastric Tone and Motility Changes Induced by a Prolonged Intraduodenal Infusion of Nutrients. Results of a Placebo-Controlled Study

Our aim was to study the 5-HT3 antagonist, ondansetron, on gastric motility changes induced by duodenal infusion of nutrients. First, the effects of a 2-hr intraduodenal infusion (IDI) of a caloric diet on antral motility were assessed. Second, a crossed-over placebo-controlled study assessed 3-day oral intake of ondansetron (8 mg bid) on gastric motility changes induced by the IDI. During the IDI, antral numbers of waves (NW) as area under curve (AUC) were lower than fasting values. After infusion, antral NW and AUC increased to return to basal values. The antral area increased slightly shortly after the start of the IDI, then remained stable. When subjects received ondansetron, the only significant motor effect was a higher antral NW and AUC during the first 30 min of the IDI (P < 0.05). After the end of the IDI, the AUC and NW increased in both the distal and the proximal antrum. The increase was lower by ondansetron in the proximal antrum. Proximal stomach relaxation induced was not influenced by ondansetron. In conclusion, an IDI of nutrients decreased antral motility, increased the antral area, and promoted fundic relaxation. This inhibitory effect was rapidly reversible. Ondansetron induced only minor motility changes in the antrum and had no effect on fundic relaxation promoted by IDI.     

Sphincter of Oddi Motility in Patients with Hepatolithiasis and Common Bile Duct Stones

The purpose of this study was to explore a difference in sphincter of Oddi (SO) motor activity among patients with intrahepatic (I, N = 5), intra- and extrahepatic (IE, N = 15), and common bile duct (CBD, N = 6) stones. Interdigestive motility of the SO and duodenum was studied by pneumohydraulic infusion manometry via the percutaneous route. SO phasic contractions showed a cyclic change in concert with the duodenal migrating motor complex (MMC) in all these patients. There was no significant difference in the cycle length, frequency, or amplitude of the SO phasic waves among the three groups throughout the whole cycle. The SO basal pressure during duodenal phases I and II of the duodenal MMC was significantly lower in patients with the IE type of hepatolithiasis than in those with the I type (P = 0.04), but there was no significant difference during phase III between the two groups. The SO basal pressure during phases I and II of the CBD group was also significantly lower than that of the I group (P = 0.02). The significance became even more prominent (P = 0.001) when a subgroup of patients with a dilated CBD (diameter > 1 cm) was examined. Lower basal pressure in the IE group or CBD group than in the I group suggested that stones in the common duct might injure or irritate the SO and cause SO dysfunction. In the subgroup with dilated CBD, which may have resulted from repeated and severe SO injury, the statistics became more prominent.     

Stereospecific Effects of Intraduodenal Tryptophan on Pyloric and Duodenal Motility in Humans

Edelbroek M, Sun W-M, Horowitz M, Dent J, Smout A, Akkermans L. Stereospecific effects of intraduodenal tryptophan on pyloric and duodenal motility in humans. Scand J Gastroenterol 1994;29: 1088-1095.

Background: L-Tryptophan delays gastric emptying in animals to a greater extent than D-tryptophan, but none of the possible motor mechanisms responsible for this stereospecific effect have been evaluated.

Methods: In 11 healthy volunteers antropyloroduodenal pressures were recorded in the fasted state with a sleeve/sidehole manometric assembly during 20-min intraduodenal infusions (2 ml-min^]) of isotonic L- AND D-tryptophan (50 mM, pH 5.7) and normal saline (pH 5.5), given in randomized order.

Results: Intraduodenal L-tryptophan increased basal pyloric pressure (p < 0.05), whereas D-tryptophan had no effect. In contrast, l- and D-tryptophan both stimulated (p < 0.05) localized phasic pyloric pressure waves, and there was no significant difference in the responses. The number of duodenal pressure waves was greater during infusion of L-tryptophan than during D-tryptophan (p<0.05).

Conclusion: We conclude that intraduodenal tryptophan has stereospecific effects on pyloric and duodenal motility. Although the precise contribution of these differential effects to gastric emptying remains to be clarified, they may be partialK responsible for the differences in gastric emptying of D-tryptophan and L-tryptophan.     

Integration of canine proximal gastric,antral, pyloric,and proximal duodenal motility during fasting and after a liquid meal

The aim was to investigate the integration of proximal gastric, antral, pyloric, and duodenal motility during fasting and after feeding. Using a proximal gastric barostat and a manometric assembly with an array of side holes astride the gastroduodenal junction, the gastrointestinal interdigestive migrating motor complex was detected in five of seven conscious fasting dogs. During phase III of the complex, which lasted a mean ± SEM of 13 ± 0.5 min, 9.6 ± 0.9 volume waves were present in the proximal stomach. The volume waves were coordinated with clusters of antral waves 64 ± 11% of the time and with inhibition of duodenal waves 91±3% of the time. A 300-ml calorie-dense liquid meal abolished the complex and promptly increased proximal gastric volume in five of six dogs. Volume waves were nearly completely suppressed, while antral waves decreased from 24 ±3.0 waves/10 min to 10±2.8 waves/10 min (P<0.05) and isolated pyloric pressure waves increased from 7.2±2.8 waves/10 min to 22±3.3 waves/10 min (P<0.005). In summary, proximal gastric motility was integrated with antral, pyloric, and duodenal motility under both fasting and fed conditions. The integrated patterns likely account for the efficient clearance of indigestible solids during fasting and the controlled emptying of nutrients with feeding.Supported in part by USPHS NIH Grants DK 18278, DK34988, and DK07198, the Winthrop Travelling Fellowship of the Royal Australasian College of Physicians, the S.K.F. (Australia) Travelling Fellowship, and the Mayo Foundation.This work was presented in part before the World Congress of Gastroenterology, Sydney, Australia, August 30, 1990     

Relation of pyloric motility to pyloric opening and closure in healthy subjects.

The relation between pyloric motor activity, opening, and closure was examined in eight healthy men. Manometry was performed with an assembly combining 13 side holes and a sleeve sensor positioned astride the pylorus. Simultaneous with manometry, pyloric opening and closure and antroduodenal contractions were observed fluoroscopically with the antrum filled with barium. During intraduodenal normal saline infusion, coordinated antral pressure waves swept over the pylorus and ejected barium into the duodenum. No localised pyloric motor pattern was observed under these conditions. In contrast, the intraduodenal triglyceride infusion was associated with the absence of antral pressure waves and virtual absence of antral wall movement. At the pylorus, there was a zone of luminal occlusion less than 1 cm long that persisted for the period of observation. This zone of luminal occlusion corresponded precisely with manometric recordings of a narrow zone of pyloric phasic and tonic activity. During the duodenal triglyceride infusion, the pylorus was closed for 98.5% of the measurement period when basal pyloric pressure was 4 mm Hg or more, and during this motor pattern, barium did not traverse the pylorus. Localised pyloric contractions cause sustained pyloric closure, whether these contractions are phasic or tonic. These contractions occur independently of antral or duodenal contractions and may interrupt gastric emptying.     

Effect of gastric distension and duodenal fat infusion on biliary sphincter of oddi motility in healthy volunteers

Although sphincter of Oddi (SO) dysfunction has been implicated in the pathogenesis of postcholecystectomy syndrome and pancreatitis, little is known about normal physiologic stimuli, such as intraduodenal fat on human SO motility. Furthermore, gastric distension that frequently accompanies endoscopic manometry has been shown in animal studies to affect SO motility. We evaluated the effects of intraduodenal fat and gastric distension on SO basal pressure. Asymptomatic volunteers had SO manometry performed while sequentially performing gastric distension and intraduodenal fat perfusion. Five subjects (ages 29.8±4.8 years, range 22–35 years) had a mean basal sphincter of Oddi pressure of 23.4±5 mm Hg (range 17–31 mm Hg). Injection of air into the stomach caused no appreciable change in either intragastric pressure or SO pressure. Intraduodenal fat infusion resulted in a decrease in mean SO basal pressure from 23.4±5.0 to 4.4±4.4 mm Hg (P=0.004). These results demonstrate that gastric distension does not affect SO basal pressure and that intraduodenal fat infusion reduces SO basal pressure.This work was presented in part at the Digestive Disease Week in Boston, Massachusetts, in May 1993.This work was supported in part by a research award from the American Society of Gastrointestinal Endoscopy.     

Antro-pyloro-duodenal motor responses to gastric and duodenal nutrient in critically ill patients

BACKGROUND: Gastric emptying is frequently delayed in critical illness which compromises the success of nasogastric nutrition. The underlying motor dysfunctions are poorly defined. AIMS: To characterise antro-pyloro-duodenal motility during fasting, and in response to gastric and duodenal nutrient, as well as to evaluate the relationship between gastric emptying and motility, in the critically ill. SUBJECTS: Fifteen mechanically ventilated patients from a mixed intensive care unit; 10 healthy volunteers. METHODS: Antro-pyloro-duodenal pressures were recorded during fasting, after intragastric administration (100 ml; 100 kcal), and during small intestinal infusion of liquid nutrient (6 hours; 1 kcal/min). Gastric emptying was measured using a (13)C octanoate breath test. RESULTS: In healthy subjects, neither gastric nor small intestinal nutrient affected antro-pyloro-duodenal pressures. In patients, duodenal nutrient infusion reduced antral activity compared with both fasting and healthy subjects (0.03 (0-2.47) waves/min v 0.14 (0-2.2) fasting (p = 0.016); and v 0.33 (0-2.57)/min in healthy subjects (p = 0.005)). Basal pyloric pressure and the frequency of phasic pyloric pressure waves were increased in patients during duodenal nutrient infusion (3.12 (1.06) mm Hg; 0.98 (0.13)/min) compared with healthy subjects (-0.44 (1.25) mm Hg; p<0.02 after 120 minutes; 0.29 (0.15)/min; p = 0.0002) and with fasting (-0.06 (1.05) mm Hg; p<0.03 after 160 minutes; 0.49 (0.13)/min; (p = 0.0001). Gastric emptying was delayed in patients (gastric emptying coefficient 2.99 (0.2) v 3.47 (0.1); p = 0.015) and inversely related to the number of pyloric pressure waves (r = -0.563, p = 0.029). CONCLUSIONS: Stimulation of pyloric and suppression of antral pressures by duodenal nutrient are enhanced in the critically ill and related to decreased gastric emptying.