Duodenal infusion of different nutrients and the site of gaseous stimulation influence intestinal gas dynamics

OBJECTIVE: Excessive intestinal gas can be involved in postprandial abdominal symptom generation, but whether the small bowel influences intestinal gas dynamics, depending on the ingested meal, remains to be demonstrated. We compare the intestinal response to a proximal and distal small intestinal gas challenge during different duodenal nutrient components. MATERIAL AND METHODS: We randomly studied 32 healthy subjects, twice, on different days with a gas mixture infused at 12 ml/min either directly into the proximal jejunum or into the ileum; during duodenal lipids, amino acids, glucose, at 1 kcal/min each, or saline (n=8 for each group). Gas evacuation was monitored continuously and abdominal perception and girth changes were assessed. RESULTS: In response to the jejunal gas challenge, duodenal lipids delayed intestinal gas clearance more potently than amino acids (733+/-26 ml and 541+/-108 ml final gas retention; p<0.001), but when gas was directly infused into the ileum the retained volumes were much smaller (271+/-78 ml and 96+/-51 ml; p<0.001). During duodenal glucose, intestinal gas clearance following jejunal or ileal gas infusion was not significantly influenced. Abdominal perception in response to the jejunal and ileal gas challenge only increased slightly during duodenal lipids (2.0+/-0.3 score and 2.3+/-0.6 score; p<0.05 versus control). CONCLUSION: Postprandial intestinal gas clearance is hampered by duodenal lipids and amino acids but not by glucose. Specific inhibitory effects are more pronounced when gas is infused into the jejunum, which underlines the importance of the small intestine in postprandial gas retention.     

Impaired small bowel gas propulsion in patients with bloating during intestinal lipid infusion

OBJECTIVE: In healthy individuals, intraluminal lipids delay intestinal gas clearance, and this reflex is exaggerated in patients with irritable bowel syndrome (IBS). Our aim was to determine the site of action of abnormal lipid-induced reflexes in IBS. METHODS: In six patients with (IBS) predominantly complaining of bloating and in six healthy subjects, a mixture of gas (N2, O2, and CO2 in venous proportions to minimize diffusion) was infused (12 mL/min) either into the jejunum or into the ileum for 2 h, with simultaneous perfusion of lipids (0.5 kcal/min) into the proximal duodenum. Rectal gas evacuation was measured by a barostat. Abdominal perception (by a 0-6 scale) and girth changes were measured at 15-min intervals. The effects of jejunal versus ileal gas infusion were compared by paired tests in random order on separate days. RESULTS: IBS patients exhibited significant gas retention during infusion of gas into the jejunum (398 +/- 90 mL vs-210 +/- 105 mL in health, p < 0.05) but not during ileal infusion (-79 +/- 87 mL vs-79 +/- 78 mL in health, NS; p < 0.05 vs jejunal infusion). Gas retention during jejunal gas infusion in IBS patients was associated with significant abdominal distension (11 +/- 3 mm girth increment vs 0 +/- 1 mm during ileal gas infusion and 1 +/- 1 mm in health, p < 0.05 for both) and abdominal symptoms (3.6 +/- 0.6 score vs 2.6 +/- 0.7 score during ileal gas infusion and 1.6 +/- 0.5 score in health, p < 0.05 for both). CONCLUSIONS: In IBS patients intraluminal lipids impair intestinal gas clearance because of upregulated reflex inhibition of small bowel transit, without appreciable colonic effects.     

Origin of gas retention and symptoms in patients with bloating

BACKGROUND & AIMS: Patients reporting abdominal bloating exhibit impaired tolerance to intestinal gas loads. The aim of this study was to identify the gut compartment responsible for gas retention. METHODS: In 30 patients predominantly reporting abdominal bloating (24 with irritable bowel syndrome and 6 with functional bloating) and 22 healthy subjects, gas (nitrogen, carbon dioxide, and oxygen) was infused into the intestine for 2 hours while measuring rectal gas outflow. First, in 12 patients and 10 healthy subjects, gas transit (24 mL/min jejunal infusion labeled with 74 MBq bolus of 133 Xe) was measured by scintigraphy. Second, in groups of patients and healthy subjects, the effects of gas infusion (12 mL/min) in the jejunum versus ileum, jejunum versus cecum, and jejunum versus sham infusion (n=6 each) were compared by paired tests. RESULTS: In patients, total gut transit of gas was delayed (50% clearance time, 33 +/- 4 min vs 23 +/- 4 min in healthy subjects; P <.05) owing to impaired small bowel transit (50% clearance time, 20 +/- 2 min vs 12 +/- 3 min in healthy subjects; P <.05), whereas colonic transit was normal (50% clearance time, 13 +/- 2 min vs 11 +/- 2 min in healthy subjects; not significant). Furthermore, jejunal gas infusion in patients was associated with gas retention (329 +/- 81 mL vs 88 +/- 79 mL in healthy subjects; P <.05), whereas direct ileal or colonic infusion was not (61 +/- 103 mL and -143 +/- 87 mL retention, respectively). CONCLUSIONS: In patients reporting bloating, the small bowel is the gut region responsible for ineffective gas propulsion.     

Role of the Jejunum Versus Ileum on Intestinal Gas Dynamics During a Balanced Meal in Healthy Subjects

Under physiological conditions, the human gut adapts intestinal gas propulsion and evacuation to prevent intestinal gaseous complaints In this study we aimed to determine influences of the jejunum versus ileum on intestinal gas dynamics during a balanced meal. Paired studies were randomly performed with seven women and three men, ages 28–42. A mixed liquid meal was infused (1 kcal/min) into the duodenum. After 30 min, gas was infused (12 ml/min) into the jejunum or ileum for 150 min. Gas expulsion was measured, and perception and girth changes were assessed. Postprandial intestinal gas propulsion was uneventful and recovery complete, with −7± 58 and −92± 44 ml final intestinal gas retention for jejunal and ileal gas infusion, respectively. Neither significant differences in abdominal perception nor changes in abdominal girth were seen. During a balanced meal, intestinal gas is effectively propulsed aborally, and this does not depend on the site of the small intestinal stimulation.     

Impaired reflex control of intestinal gas transit in patients with abdominal bloating

BACKGROUND: Patients with abdominal bloating and distension exhibit impaired transit of intestinal gas which may lead to excessive gas retention and symptoms. Furthermore, we have previously shown that intestinal gas transit is normally accelerated by rectal distension. We hypothesise that in patients with functional bloating this modulatory mechanism fails and impairs gas transit. METHODS: In 12 healthy subjects and eight patients with abdominal bloating we compared, by paired studies, the effect of rectal versus sham distension on intestinal gas transit. Gas was infused into the jejunum (12 ml/min) for three hours with simultaneous perfusion of lipids into the duodenum (Intralipid 1 kcal/min) while measuring evacuation of gas per rectum. RESULTS: In healthy subjects, duodenal lipid infusion produced gas retention (409 (68) ml) which was prevented by rectal distension (90 (90) ml; p<0.05 v sham distension). In contrast, rectal distension in patients with abdominal bloating failed to reduce lipid induced gas retention (771 (217) ml retention during rectal distension v 730 (183) ml during sham distension; NS; p<0.05 v healthy controls for both). CONCLUSION: Failure of distension related reflexes impairs intestinal gas propulsion and clearance in patients with abdominal bloating.     

Study of the effect of ileal distension on the motor activity of the jejunum, and of jejunal distension on the motor activity of the ileum

BACKGROUND/AIMS: The effect of ileal distension on the jejunal motor activity and ofjejunal distension on the ileal motility have been poorly addressed in the literature. We investigated the hypothesis that distension of either ileum or jejunum would affect the motile activity of the other. METHODOLOGY: Response of jejunal pressure to ileal balloon distension and of ileal pressure to jejunal distension in increments of 2 mL of normal saline were recorded in 18 dogs. The test was performed after individual local anesthetization of the ileum and jejunum and was repeated using saline instead of lidocaine. RESULTS: Ileal distension with 2, 4, and 6mL of saline produced no jejunal pressure response (p >0.05), while 8- and up to 12-mL distension effected jejunal pressure decrease (p<0.05). Jejunal distension up to 6mL did not change ileal pressure (p>0.05); distension with 8, 10, and 12 mL reduced it (p<0.05). Jejunal or ileal pressure responses were maintained as long as ileal or jejunal distension was continued. Distension of the anesthetized ileum or jejunum did not produce significant pressure changes in either. CONCLUSIONS: Jejunal or ileal pressure decrease and presumably hypotonia upon large-volume ileal or jejunal, respectively, distension postulate reflex relationship which we call 'ileal-jejunal and jejuno-ileal inhibitory reflex'. These reflexes appear to regulate chyme flow in small intestine by creating a balance of chyme delivery between the jejunum and ileum. Reflex derangement in neurogenic and myogenic diseases may result in gastrointestinal disorders, a point that needs to be investigated.     

Adaptive changes in postprandial motility after intestinal resection and bypass

An electromyographic technique was used to study the changes in postprandial motility induced by jejunal and ileal resection and jejunal bypass (50% reduction of total length of small bowel). Electrodes were implanted in rats throughout the intestine. Compared to control animals, the duration of postprandial interruption of the myoelectric complex (DIMC) was rapidly increased after jejunal resection, more gradually augmented after jejunal bypass, and remained constant after ileal resection. The frequency of occurrence of spike bursts during the postprandial period was significantly decreased in the short remaining proximal segment after jejunal resection and was not changed in the ileum. The jejunal bypass induced no change in the frequency throughout the remaining bowel. Ileal resection was followed by a decrease on the jejunum. The percentage of slow waves superimposed by a spike burst remained constant after jejunal resection and bypass but was significantly decreased after ileal resection on the whole remaining intestine. These results show important modifications in postprandial motor activity of the small bowel, which appear rapidly after jejunal resection, more gradually after jejunal bypass, and which are less pronounced after ileal resection. This electromyographic study emphasizes the role of intestinal motility in the development of adaptation after small bowel resection or bypass.     

Further characterisation of the 'ileal brake' reflex in man--effect of ileal infusion of partial digests of fat, protein, and starch on jejunal motility and release of neurotensin, enteroglucagon, and peptide YY.

Previous studies have shown that ileal infusion of partially digested triglyceride inhibits jejunal motility. The partial digest used in those studies contained a mixture of glycerol, free fatty acid, mono-, di-, and triglycerides. In Part I of the present study we have separately infused emulsions containing either glycerol 3.1 g (n = 6), oleic acid 9.6 g (n = 6), triolein 10 g (n = 12), or medium chain triglycerides 10 g (n = 6) into the ileum and have recorded the effect this has on jejunal motility. Five further subjects received infusions of partial hydrolysates of corn starch 10 g and lactalbumin 7 g. Marked inhibition of jejunal pressure wave activity was seen after all three lipid infusions, per cent activity falling from a control of 37.7 (7.7) to 6.2 (2.1) and 22.4 (8.2)% 30 min after completing the oleic acid and triolein infusions respectively, and from a control value of 39.5 (4.1) to 17.7 (4.7) after MCTs (all p less than 0.05). No significant fall occurred after infusion of glycerol, protein or carbohydrate. All three lipid infusions raised plasma concentrations of neurotensin, enteroglucagon and peptide YY equally effectively, although only the rise in peptide YY correlated significantly with the inhibition of jejunal pressure wave activity (r = 0.80, n = 6, p less than 0.05). In Part II of this study six subjects received a 3 ml/min jejunal infusion of an isotonic carbohydrate saline solution followed after three hours by a similar infusion of a partial digest of lipid. During each infusion flow and transit time was measured by marker and dye dilution. Jejunal infusion of the carbohydrate-saline solution was associated with low jejunal flow, 4.7 (1.0) ml/min and a mean transit time through the 50 cm study segment of 36.5 (7.1) min. By contrast jejunal infusion of partially digested triglyceride was associated with a markedly increased flow, 9.0 (1.2) ml/min, a fall in mean transit time to 20.3 (2.6) min and significant rises in pancreaticobiliary secretions. Jejunal triglyceride also increased the incidence of prolonged high amplitude jejunal pressure waves in four of six subjects. These studies suggest that there are important differences in the jejunal response to ileal versus jejunal lipid. While long and median chain free fatty acids infused into the ileum exert an inhibitory effect on jejunal motility, when infused directly into the jejunum partially digested triglyceride accelerates transit, increases jejunal flow and subtly alters the pattern of jejunal contractions.     

Sandostatin impairs postresection intestinal adaptation in a rat model of short bowel syndrome

Because of its antisecretory properties, sandostatin has been advocated for the treatment of patients with short bowel syndrome (SBS). This study was conducted to determine the effect of sandostatin on structural intestinal adaptation, cell proliferation and apoptosis in a rat model of SBS. Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection, SBS rats underwent 75% small bowel resection, and SBS-sandostatin rats underwent bowel resection and were treated with sandostatin (SBS-SND). Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 14 following operation. We have demonstrated that SBS-SND animals demonstrated lower (vs SBS rats) duodenal and jejunal bowel weights, jejunal and ileal mucosal weight, jejunal and ileal mucosal DNA and protein, jejunal and ileal villus height, cell proliferation index in the ileum, and enterocyte apoptosis in jejunum and ileum. We conclude that in a rat model of SBS sandostatin decreases cell proliferation and inhibits structural intestinal adaptation.     

Vagotomy inhibits the jejunal fluid secretion activated by luminal ileal Escherichia coli STa in the rat in vivo

BACKGROUND: Escherichia coli heat stable enterotoxin (STa) is a major cause of secretory diarrhoea in humans. AIMS: To assess the effects of instilling STa into the ileum on remote fluid secretion in the jejunum and colon in rats in vivo by a gravimetric technique. METHODS AND RESULTS: Ileal STa (55 ng/ml) stimulated fluid secretion in both ileal and jejunal loops but not in the colon. The fluid secretion induced by ileal STa was inhibited by L-NAME (Nomega-nitro-L-arginine methyl ester, 40 mg/kg intraperitoneally) but not by D-NAME (Nomega-nitro-D-arginine methyl ester). Ileal carbachol (183 mg/ml) instilled into the lumen stimulated ileal secretion but not jejunal secretion, and was unaffected by L-NAME. Capsaicin (10 microM), instilled luminally with STa in the ileum, blocked both the ileal and jejunal fluid secretion. Acute bilateral vagotomy prevented luminal ileal STa from inducing jejunal fluid secretion but not from activating ileal fluid secretion. CONCLUSION: Ileal E coli STa stimulates remote secretion in the rat jejunum but not in the colon, probably by a nitrinergic, vagal reflex mediated by C fibres. This neural pathway will amplify the action of the toxin in its generation of secretory diarrhoea.     

Plasma enteroglucagon levels in different models of intestinal resection in the rat

To assess the influence of the different intestinal segments on the plasma enteroglucagon level, three models of intestinal resection in the rat were studied (jejunal, ileal, 90%). The basal values for this peptide and those obtained after an infusion of intraduodenal glucose were compared. The results obtained in basal/post-glucose infusion were: 50% proximal (jejunum): 220/728 pg/ml; 50% distal (ileum): 10/233 pg/ml; and the middle 90%: 108/297 pg/ml. The glucose infusion produced a maximal response, permitting a better evaluation of the differences among the three resection models. The highest levels corresponded to the group in which the entire ileum was conserved.     

Comparisons of the effects on satiety and eating behaviour of infusion of lipid into the different regions of the small intestine.

Food intake and feelings of hunger and fullness were monitored in paired studies carried out in two groups of six healthy non-obese male volunteers during infusion of isotonic solutions of either a 50% corn oil emulsion or saline into the jejunum or into the ileum. Infusion of the lipid emulsion at a rate of 1.2 ml/min (4.9 kcal/min) into either the ileum or the jejunum significantly reduced the period of eating (p less than 0.01) and the quantity of food consumed (p less than 0.01), but neither affected the rates of drinking or the amount of fluid consumed. Infusion of the lipid emulsion into the jejunum also significantly reduced the sensations of hunger before the meal (p less than 0.05), and the rate of ingestion (p less than 0.01). Ileal infusion did not influence these indices. The results suggest that jejunal and ileal infusion of lipid reduces the size of the meal that could be consumed possibly by inhibiting gastric emptying. The alleviation of hunger before ingestion and the slower rate of eating, however, suggests that jejunal lipid activates an additional mechanism that influences the appetite centre in the hypothalamus directly.     

Functional differentiation of human jejunum and ileum: A comparison of the handling of glucose, peptides, and amino acids

The characteristics of glucose, glycine, L-alanine, and glycyl-L-alanine absorption from the jejunum and ileum have been compared in normal human subjects. A perfusion technique has been used, and correct positioning of the perfusion tube has been confirmed by measuring the differential jejunal and ileal handling of bicarbonate.

Glucose and glycine were absorbed faster from the jejunum than from the ileum of all subjects studied, and L-alanine was absorbed faster from the jejunum than from the ileum in five out of six subjects studied. In contrast, the dipeptide glycyl-L-alanine was absorbed at comparable rates from the jejunum and ileum. Higher concentrations of free amino acids were detected in the luminal contents aspirated during the ileal dipeptide perfusions.

These results emphasize the importance of oligopeptide transport in the absorption of protein digestion products, especially in the human ileum, and the practical implications of these findings are discussed.

     

Physical activity and intestinal gas clearance in patients with bloating

BACKGROUND: Patients complaining of abdominal bloating have impaired tolerance and clearance of intestinal gas loads. Mild exercise enhances intestinal clearance and prevents retention of intestinal gas loads in healthy subjects. Our aim was to evaluate the putative beneficial effects of physical activity in patients with abdominal bloating. METHODS: In eight patients complaining of bloating, seven with irritable bowel syndrome, and one with functional bloating, according to Rome II criteria, a gas mixture was continuously infused (12 mL/min) into the jejunum for 120 min with simultaneous duodenal lipid perfusion (1 kcal/min). Gas evacuation, perception (0-6 scale), and abdominal girth were measured at 15-min intervals. Paired studies were randomly performed in the supine position during intermittent pedaling (5 min with 3-min rest intervals at 40 rpm and 0.15 kp load) versus rest (as control). RESULTS: During rest, a significant proportion of the gas infused was retained in the gut (45 +/- 9%, P < 0.01 vs basal), but retention was significantly lower during exercise (24 +/- 7%, P < 0.05 vs rest). Gas retention during rest was associated with significant abdominal symptoms (3.6 score; P < 0.01 vs basal), and symptoms also improved during exercise (2.8 score, P < 0.05 vs rest). During the test, patients developed abdominal distension, which was related to the volume of gas retained (r = 0.68, P < 0.05). CONCLUSION: Mild physical activity enhances intestinal gas clearance and reduces symptoms in patients complaining of abdominal bloating.     

Intestinal regrowth is amplified after jejunal but not ileal resection during tapeworm infection in the rat

The ileum possesses functions required by a healthy individual that are not fully supplanted by the duodenum or jejunum. Evidence suggests that the ileum may also be necessary to maintain an enteric parasite–host interaction. We hypothesized that the ileum is essential to the survival of the lumen-dwelling, rat tapeworm, H. diminuta. Male rats were divided into three groups: those with ileal or jejunal resections and nonresected controls. Half of each rat group was infected with the tapeworm. After jejunal resection, the weight but not length of intestinal remnant (duodenum + ileum) in infected rats returned to that of control, nonresected intestine 29 days after surgery and tapeworm numbers were fully maintained. In contrast, after ileal removal intestinal length and weight of the remaining duodenum and jejunum in infected rats were significantly decreased and tapeworm survival diminished. Data indicates that intestinal growth following resection is amplified by tapeworm infection when the ileum remains but diminished when the ileum is removed. Furthermore, loss of the ileum results in decreased infection intensity and dry weight of the tapeworm.     

Release of neurotensin by selective perfusion of the jejunum with oleic acid in dogs

Plasma neurotensin concentrations are rapidly elevated after oral ingestion or intraduodenal infusion of fat, apparently before fat reaches the ileum where neurotensin is highly concentrated. The purpose of this study was to investigate the site of neurotensin release and to determine whether neurotensin is released by direct luminal stimulation by fat in conscious dogs. Dogs were prepared with isolated jejunal or ileal segments and portal vein catheters. Release of neurotensin into the portal venous blood was examined by selective perfusion of each intestinal segment with sodium oleáte. The results of this study show that selective perfusion of the jejunum, but not the ileum, with sodium oleate, caused a significant release of neurotensin. We speculate that release of ileal neurotensin is not due to direct luminal stimulation, but is mediated by local neural or humoral intermediates.     

Trophic effects of neurotensin in massive bowel resection in the rat

The trophic effect of the administration of exogenous neurotensin on the intestinal mucosa was studied in rats following an 80% bowel resection. Villus length and mucosal DNA content were assessed in the jejunal and ileal mucosa of the remnant intestine 14 days after resection. The data obtained in an 80% resected control group (80% group) and an experimental group receiving an infusion of neurotensin (300 µg/kg/day) for 14 days subcutaneously (80%+NT group) were compared. The results indicate that the administration of exogenous neurotensin (80%+NT) increases villus length (jejunum: 920±77 vs 861±25 µm and ileum length: 975±23 vs 875±99 µm) to an extent greater than that observed in the 80% resected group not receiving exogenous neurotensin. The levels of mucosal DNA per milligram of protein increased significantly in both groups but was paradoxically less in the 80%+NT group than in the 80% resection group (jejunum: 8±0.56 vs 10.18±0.80; ileum; 8.63±0.43 vs 10.05±0.46). These data suggest that the administration of exogenous neurotensin to the rat potentiates the growth of intestinal villi and accelerates the intestinal trophic response seen following massive bowel resection. The increase in circulating enteroglucagon levels noted after neurotensin administration (80%+NT: 547±48 pg/ml vs 80%: 341±41 pg/ml) suggests that some of the trophic effects of neurotensin may be mediated, at least in part, by enteroglucagon. These data also suggest a potential role for the use of neurotensin in the initial treatment of individuals with short bowel syndrome.     

Lipid-induced intestinal gas retention in irritable bowel syndrome

BACKGROUND & AIMS: We hypothesized that lipids, which induce various motor and sensory effects on the gut, modulate intestinal gas dynamics and that alteration of this regulatory mechanism may result in impaired gas transit in patients with irritable bowel syndrome (IBS). METHODS: In 45 healthy subjects and 30 patients with IBS, evacuation of gas infused into the jejunum (at 12 mL/min) was measured for 2 hours. The effect of simultaneous duodenal perfusion of lipids at 0 kcal/min (saline), 0.5 kcal/min, and 1 kcal/min was tested in groups of 15 subjects each. RESULTS: In healthy subjects, duodenal lipids at 1 kcal/min but not at 0 kcal/min or 0.5 kcal/min produced significant gas retention (281 +/- 53 mL vs. 22 +/- 64 mL at 0 kcal/min and -65 +/- 72 mL at 0.5 kcal/min; P < 0.05 for both). Patients with IBS exhibited gas retention during saline perfusion (259 +/- 85 mL at 0 kcal/min; P < 0.05 vs. healthy subjects) and were hypersensitive to duodenal lipids (505 +/- 61 mL retention at 0.5 kcal/min; P < 0.05 vs. saline and vs. healthy subjects). The "gas plus lipids" challenge test discriminated patients with 100% sensitivity and 93% specificity. CONCLUSIONS: Physiologic concentrations of intestinal lipids exert an inhibitory control on intestinal gas transit, and this mechanism is up-regulated in patients with IBS. Hence, impaired gas propulsion, shown by the gas challenge test, may be useful as a diagnostic test if replicated in a larger series of patients.     

Jejunal brake

Optimal absorption of fat requires adequate time of contact with the absorptive sites of the small intestine. In order to prevent steatorrhea, intestinal transit must be slowed in response to the fat that has emptied into the small intestine. Intestinal transit is known to be inhibited by fat in the ileum via the ileal brake. This response has suggested that the regulation of intestinal transit is a function of the distal small intestine. However, clinical observations suggest that the ileal brake is not the only control mechanism for intestinal transit. In short bowel patients with resection of the ileum, the proportion of fecal fat recovery remained constant even after the fat intake was increased threefold. In these patients, optimal fat absorption based on the slowing of intestinal transit must have been triggered by an inhibitory mechanism located outside of the distal small intestine. To test the hypothesis that fat in the proximal small intestine inhibited intestinal transit, we compared intestinal transit during perfusion of the proximal half of the small intestine with 0 (buffer only), 15, 30, or 60 mM oleate in dogs equipped with duodenal and mid-intestinal fistula. Intestinal transit across a 150-cm test segment (between fistulas) was measured by counting for the recovery of a radioactive marker in the output of the mid-intestinal fistula during the last 30 min of a 90-min perfusion. We found that oleate inhibited intestinal transit in a load-dependent fashion (P<0.005). Specifically, while the mean cumulative recovery of the transit marker was 95.5% during buffer perfusion, the recovery decreased when 15 mM (64.3%), 30 mM (54.7%), or 60 mM oleate (38.7%) was perfused into the proximal half of the small intestine. We conclude that fat in the proximal small intestine inhibits intestinal transit as the jejunal brake.     

Study of the effect of jejuno-ileal distension on the motor activity of the stomach with evidence of "entero-gastric inhibitory reflex"

BACKGROUND/AIMS: In chronic constipation due to delayed colonic transit, stasis of the ileal contents with resulting ileal distension may occur. The current study investigated the effect of ileal and jejunal distension on the gastric motility, aiming at elucidating the possible existence of a relationship and its role in the flow through the gut. METHODOLOGY: The response of the gastric pressure to ileal and jejunal balloon distension in increments of 2 mL of saline was recorded in 12 mongrel dogs. The test was repeated after separate local anesthetization of the ileum, jejunum and stomach. RESULTS: 2- and 4-mL ileal balloon distension produced no significant gastric pressure response, while 6- and up to 10-mL distension effected decrease of the antral and corporeal pressures (p < 0.05, p < 0.05, respectively). Jejunal distension produced a gastric pressure decline (p < 0.05) with 4 and up to 10 mL of saline. The gastric pressure decrease did not show significant changes with the various distending volumes. It was maintained as long as ileal or jejunal distension was continued. Distension of the anesthetized ileum or jejunum caused no gastric pressure changes, nor did ileal or jejunal distension produce pressure changes in the anesthetized stomach. CONCLUSIONS: The gastric pressure decline and presumably hypotonia upon ileal or jejunal distension with big volumes postulate a reflex relationship which we call "entero-gastric inhibitory reflex". The small intestine is suggested to slow down gastric emptying through this reflex. A balance is thus created between chyme delivery from the stomach and chyme processing by the small intestine. Reflex derangement in neurogenic and myogenic diseases may result in gastrointestinal disorders, a point that needs to be investigated.