Intestinal myoelectrical activity and transit time in chronic portal hypertension

1992 ◽  
Vol 263 (4) ◽  
pp. G474-G479 ◽  
Author(s):  
J. J. Stewart ◽  
H. D. Battarbee ◽  
G. E. Farrar ◽  
K. W. Betzing
Keyword(s):  
Small Intestine ◽  
Portal Hypertension ◽  
Portal Vein ◽  
Transit Time ◽  
Experimental Period ◽  
Phase Iii ◽  
Adult Rats ◽  
Myoelectrical Activity ◽  
Distal Small Intestine ◽  
Proximal Small Intestine

This study was designed to determine the effects of portal hypertension on intestinal myoelectrical activity and propulsion. In a single surgery, adult rats were implanted with a serosal electrode at each quarter of the small intestine, and portal hypertension was produced by calibrated constriction of the portal vein. To determine intestinal transit, portal vein-stenosed (PVS) and sham-operated animals were chronically implanted with a catheter in the proximal small intestine. Transit time was determined by measuring the progression of radioactive chromium along the bowel. Studies were conducted 6, 9, and 14 days after surgical preparation. Portal hypertension was associated with both transient and persistent changes in intestinal myoelectrical activity during the experimental period. Slow wave frequency was significantly reduced in the proximal small intestine on all test days and in the distal small intestine on day 14. Occurrence of the migrating myoelectric complex was reduced on days 6 and 9. Phase III amplitude was significantly reduced in the distal small intestine on all test days. Changes in intestinal myoelectrical activity in PVS animals were not associated with measurable changes in intestinal propulsion. The results suggest that both transient and persistent changes in intestinal myoelectrical activity occur during the 2-wk period after portal vein stenosis. The functional significance of the changes is unknown.

scholarly journals The development of arylsulphatase in the small intestine of the rat

1969 ◽  
Vol 114 (2) ◽  
pp. 343-350 ◽  
Author(s):  
S. H. Danovitch ◽  
L. Laster
Keyword(s):  
Small Intestine ◽  
Specific Activity ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Ph Optimum ◽  
Distal Small Intestine ◽  
Sprague Dawley Rats ◽  
Proximal Small Intestine ◽  
Liver And Kidney ◽  
Old Rats

1. Arylsulphatase activity was measured in stomach, proximal and distal third of small intestine, colon, liver and kidney of foetal and neonatal Sprague–Dawley rats and Swiss mice, with nitrocatechol sulphate as substrate. 2. The specific activity in the distal small intestine, but not in the stomach, proximal small intestine or colon, increased about fourfold between 5 and 16 days after birth in both conventional and germ-free rats. 3. No comparable increase occurred in the distal small intestine of the mouse. 4. The specific activity of acid phosphatase in the distal small intestine of the rat rose only slightly when the arylsulphatase activity increased. 5. The pH optimum and Michaelis constant of arylsulphatase activity of the distal small intestine were similar for 1-day-old, 9-day-old and adult rats. 6. When extracts of distal small intestine of 1-day-old and 9-day-old rats were incubated together, the arylsulphatase activities were additive.

Age- and tissue-specific induction of NHE3 by glucocorticoids in the rat small intestine

2000 ◽  
Vol 278 (4) ◽  
pp. C629-C637 ◽  
Author(s):  
Pawel R. Kiela ◽  
Yigit S. Guner ◽  
Hua Xu ◽  
James F. Collins ◽  
Fayez K. Ghishan
Keyword(s):  
Small Intestine ◽  
Glucocorticoid Receptor ◽  
Western Blot ◽  
Mrna Level ◽  
Rat Small Intestine ◽  
Adult Rats ◽  
Tissue Specific ◽  
Distal Small Intestine ◽  
Proximal Small Intestine ◽  
Specific Induction

Of the two known apical isoforms of the Na+/H+ exchanger (NHE) family, only the NHE3 gene is regulated by glucocorticoids. The aim of these studies was to investigate the mechanisms underlying the effects of methylprednisolone (MP) on expression of NHE3 in the proximal and distal small intestine of suckling and adult rats. Immunoblots showed that the glucocorticoid responsiveness in the proximal small intestine was greatest in suckling animals (NHE3/β-actin: 0.43 ± 0.09 control vs. 1.57 ± 0.15 MP; P < 0.001), and responsiveness decreased with age with no effect in adults (0.56 ± 0.14 vs. 0.64 ± 0.17). Distal small intestine was responsive only in adult rats (0.49 ± 0.13 vs. 1.65 ± 0.09; P < 0.001). This pattern was confirmed at the mRNA level and by 22Na+ uptake. Western blot and [3H]dexamethasone mesylate binding showed that the responsiveness of NHE3 to glucocorticoids is directly related to the expression of glucocorticoid receptor (GR) in the small intestine. These studies suggest that loss and gain of glucocorticoid responsiveness in the proximal and distal small intestine, respectively, are related to age- and segment-dependent expression of GR.

scholarly journals Localization of Astrovirus in Experimentally Infected Turkeys as Determined by In Situ Hybridization

2002 ◽  
Vol 39 (5) ◽  
pp. 595-598 ◽  
Author(s):  
E. Behling-Kelly ◽  
S. Schultz-Cherry ◽  
M. Koci ◽  
L. Kelley ◽  
D. Larsen ◽  
...  
Keyword(s):  
Small Intestine ◽  
In Situ Hybridization ◽  
Experimental Period ◽  
Intestinal Epithelial ◽  
Distal Small Intestine ◽  
Turkey Poults ◽  
Proximal Small Intestine ◽  
Crypt Hyperplasia ◽  
Negative Sense

Twenty-one 3-day-old turkey poults from British United Turkeys of America were orally inoculated with a recently characterized astrovirus, TAstV-2, isolated from turkeys with poult enteritis and mortality syndrome. At 1, 2, 3, 4, 5, 7, and 9 days postinfection (dpi), three inoculated birds were euthanatized, and tissues (intestines, spleen, bursa, and thymus) were collected immediately into 10% neutral buffered formalin. Inoculated birds were diarrheic by 3 dpi, and frothy feces persisted throughout the experimental period. Histologically, there was only slight evidence of enteric damage, which was characterized by mild epithelial necrosis, lamina propria infiltrates, minimal villus atrophy, and mild crypt hyperplasia. In situ hybridization, using a negative sense digoxigenin-labeled riboprobe to the capsid gene of TAstV-2, revealed viral RNA in intestinal epithelial cells at the basal margins of the villi, in distal small intestine, and in cecum at 2 dpi, with subsequent extension to epithelium of the large intestine and proximal small intestine (3–5 dpi). Minimal virus remained by 9 dpi.

Intraluminal lipids modulate avian gastrointestinal motility

1995 ◽  
Vol 269 (2) ◽  
pp. R445-R452 ◽  
Author(s):  
V. Martinez ◽  
M. Jimenez ◽  
E. Gonalons ◽  
P. Vergara
Keyword(s):  
Small Intestine ◽  
Oleic Acid ◽  
Gastric Emptying ◽  
Electrical Activity ◽  
Transit Time ◽  
Gastrointestinal Motility ◽  
Phase Iii ◽  
Intestinal Transit Time ◽  
Speed Of Propagation ◽  
Spike Bursts

Infusion of lipids into the ileum delays gastric emptying and intestinal transit time in some species. The aim of this study was to characterize the actions of intraluminal lipid infusion on gastrointestinal electrical activity in chickens. Animals were prepared for electromyography with chronic electrodes in stomach, duodenum, and small intestine. Two catheters were chronically placed in the esophagus and ileum to infuse equimolar doses of either oleic acid (OA) or triolein (TO). Both OA and TO, esophageally infused, inhibited the frequency of the gastroduodenal cycle and increased the frequency of antiperistaltic spike bursts in the duodenum. Ileal infusion of OA, but not of TO, produced the same effects. Both esophageal and ileal OA infusion increased the duration of the migrating myoelectric complex (MMC) and decreased the speed of propagation of phase III. In conclusion, intraluminal infusion of lipids modulates gastrointestinal motility by decreasing the frequency of the gastric cycle, increasing duodenogastric refluxes, and elongating the MMC. These actions could delay gastric emptying and increase transit time, which suggests the presence of an "ileal brake" mechanism similar to that described in mammals.

Transport of butyric acid in vascularly perfused anuran small intestine: importance of pH and anion transport

1986 ◽  
Vol 250 (4) ◽  
pp. G469-G474
Author(s):  
D. Hollander ◽  
E. M. Gerard ◽  
C. A. Boyd
Keyword(s):  
Small Intestine ◽  
Butyric Acid ◽  
Nonlinear Function ◽  
Anion Transport ◽  
Transport Protein ◽  
Disulfonic Acid ◽  
Flux Analysis ◽  
Acid Transport ◽  
Distal Small Intestine ◽  
Proximal Small Intestine

Butyric acid transport was studied in the isolated, vascularly perfused frog small intestine. At luminal butyric acid concentrations of 5-50 mM, absorption was a nonlinear function of the luminal concentration, whereas the relationship of absorption to concentration remained linear at 0-1,000 microM. The most important factor regulating the rate and direction of butyric acid transport was the pH. We used unidirectional flux analysis to determine net transport across the epithelium while the pH of the luminal or vascular compartments was changed. We found a four- to fivefold decrease in butyric acid transport into the portal circulation as the lumen pH was increased from 6.0 to 8.0. The pH of the vascular perfusate influenced the vascular-to-lumen transport of butyric acid in the same proportions. The second important regulatory factor of butyric acid transport was the 4,4'-diisothiocyananostilbene-2,2'-disulfonic acid (DIDS)-sensitive anion transport protein. DIDS added to the lumen at 10(-6) M decreased butyric acid transport by approximately 40% at pH 7.4. DIDS also inhibited butyric acid transport when added to the vascular perfusate or when transport was measured in a vascular-to-lumen direction. We suggest that, at the relatively low pH of the proximal small intestine, butyric acid becomes protonated and lipophilic and is mainly transported directly through the cell membrane. At the more alkaline pH of the distal small intestine butyric acid is in the ionized form and transport by the DIDS-sensitive anion transport protein may predominate.

Pancreaticobiliary factors in the modulation of small intestinal enterokinase in the rat

1986 ◽  
Vol 250 (1) ◽  
pp. G103-G108 ◽  
Author(s):  
B. M. Newman ◽  
P. C. Lee ◽  
H. Tajiri ◽  
D. R. Cooney ◽  
E. Lebenthal
Keyword(s):  
Small Intestine ◽  
Bile Acids ◽  
Common Duct ◽  
Complete Loss ◽  
Adult Rats ◽  
Brush Border Enzymes ◽  
Proximal Small Intestine ◽  
Trophic Changes ◽  
The Common ◽  
Small Intestinal

Chronic pancreaticobiliary diversion was employed to study the modulation of enterokinase in the small intestine of adult rats. Diversion resulted in apparent trophic changes of the proximal bypassed portion of the intestinal mucosa. An almost complete loss of mucosal enterokinase activity in the proximal duodenum but no increase of enterokinase in the segments distal to reentry of the common duct was found in the pancreaticobiliary-diverted rats. The effect on the enterokinase activity in the proximal segment was specific in that no other brush-border enzymes measured in that segment were decreased. The decrease in enterokinase was partially prevented by dietary supplementation with pancreatic trypsinogen and completely avoided with the addition of a combination of bile acids and trypsinogen. Supplementation with bile acid alone did not preserve the enterokinase levels in the bypassed rats. The results suggested that trypsinogen is the primary factor responsible for modulating enterokinase levels in the proximal small intestine, with bile acids acting as a modifier.

Intestinal myoelectric alterations in rats chronically infected with the tapeworm Hymenolepis diminuta

1994 ◽  
Vol 267 (5) ◽  
pp. G851-G858 ◽  
Author(s):  
M. B. Dwinell ◽  
P. Bass ◽  
J. A. Oaks
Keyword(s):  
Small Intestine ◽  
Potential Gradient ◽  
Hymenolepis Diminuta ◽  
Phase Iii ◽  
Myoelectric Activity ◽  
Spike Potential ◽  
Bipolar Electrodes ◽  
Distal Small Intestine ◽  
Potential Activity ◽  
Interdigestive Motility

This study determined that intestinal myoelectric activity was profoundly altered during a strictly luminal, chronic, tapeworm infection. Chronically implanted bipolar electrodes were attached to five sites on the serosal surface of the rat small intestine. One was placed on the duodenum, three on the jejunum, and the fifth on the ileum. Electromyographic recording in nonfasted unanesthetized animals was begun at day 5 postsurgery. All electromyographic recordings were analyzed for slow wave (SW) frequency, phase III frequency, duration of phase III, and percentage of SW with spike potentials. Three initial control recordings prior to infection confirmed the presence of normal interdigestive motility characterized by the three phases (I, II, III) of the migrating myoelectric complex (MMC). Two nonpropulsive myoelectric alterations were observed in infected animals: the repetitive bursts of action potentials (RBAP) and periods of sustained spike potentials (SSP). Myoelectric activity from infected animals indicated decreased cycling of the interdigestive MMC. RBAP and SSP were more prevalent in the distal small intestine corresponding to tapeworm location. The percent of spike potential activity indicated that there was a reversal in the spike potential gradient on the small intestine. The number of spike potentials was maximal in caudal and minimal in oral intestine. We propose that overall localized increases in myoelectric spike potential activity represent increased contractility and decreased propulsion triggered by the presence of the tapeworm. These motility changes were surprising, since the tapeworm Hymenolepis diminuta does not penetrate the intestinal mucosa. This interaction between parasite and host may prevent expulsion of the tapeworm from the small intestine.

Variation in Rotavirus Virulence: A Comparison of Pathogenesis in Calves between Two Rotaviruses of Different Virulence

1993 ◽  
Vol 30 (3) ◽  
pp. 223-233 ◽  
Author(s):  
G. A. Hall ◽  
J. C. Bridger ◽  
K. R. Parsons ◽  
R. Cook
Keyword(s):  
Small Intestine ◽  
Virulent Strain ◽  
Villus Height ◽  
Distal Small Intestine ◽  
Cytopathic Effects ◽  
Proximal Small Intestine ◽  
Viral Particles ◽  
Virulent Virus ◽  
The Mean ◽  
Spread Of Infection

Variation in virulence between two bovine rotaviruses was investigated using ten female and ten male 10-day-old gnotobiotic calves of five breeds or cross breeds that were inoculated with a virulent strain or a strain of low virulence. Similar numbers of infectious viral particles were detected in feces of calves inoculated with either virus, but diarrhea, xylose malabsorption, and reduction of villus height occurred only after inoculation with virulent virus. The mean percentage of the area of the villus epithelium per villus immunostained for rotavirus antigen was eight times greater in calves inoculated with virulent virus, and the mean percentage of villi on which immunostained enterocytes were detected was twice as large in calves inoculated with virulent virus than in calves inoculated with the virus of low virulence. Mean crypt death and mean crypt cell production rates were increased after inoculation with either virus. Virulence was associated with extensive spread of infection through the small intestine, preferential colonization of the proximal small intestine, and marked damage to enterocytes and villi. The virus of low virulence infected the proximal small intestine poorly, and although it infected more enterocytes in the mid and distal small intestine and replicated in them, causing cytopathic effects, it did not damage intestinal structure and affect function.

Localization of cholesterol synthesis along villus-crypt axis in diabetic rats

1987 ◽  
Vol 253 (3) ◽  
pp. G336-G344
Author(s):  
K. R. Feingold ◽  
A. H. Moser
Keyword(s):  
Small Intestine ◽  
Cholesterol Synthesis ◽  
Cell Mass ◽  
Diabetic Rats ◽  
Major Site ◽  
Distal Small Intestine ◽  
Proximal Small Intestine ◽  
Cell Layers ◽  
Cell Fractions ◽  
Crypt Cells

In diabetic animals cholesterol synthesis is increased in the small intestine, and this increase occurs in all segments along the duodenal-ileal axis. In the present study we have determined the sites along the villus-crypt axis in which cholesterol synthesis is increased. In diabetic animals cholesterol synthesis is increased in the proximal small intestine, and this is chiefly due to an increased synthesis in the crypt cells. In the midintestine cholesterol synthesis is increased in all cell fractions, but again the crypt cells are the major site accounting for the increase. In the distal small intestine synthesis is increased in all cell fractions, but the increase is greatest in the upper villus cells. Thus the basis for the increase in intestinal cholesterol synthesis in diabetic animals is dependent on location. Additionally, in the proximal small intestine the increase in synthesis is due to an increased mass of cells, whereas in the distal small intestine the increase is due to an increased synthesis per unit of tissue. In cholesterol-fed diabetic animals we observed a decrease in cholesterol synthesis in the proximal and midintestine that was due to a decrease in synthesis in all cell fractions. This decrease in synthesis is accounted for by a decrease in synthesis per unit of tissue. Restricting food intake in the diabetic animals decreased cholesterol synthesis in all cell layers, and this decrease is due to a decrease in cell mass.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of a chronic subclinical infection ofTrichostrongylus colubriformison gastrointestinal motility and digesta flow in sheep

Parasitology ◽  
1985 ◽  
Vol 91 (2) ◽  
pp. 381-396 ◽  
Author(s):  
P. C. Gregory ◽  
G. Wenham ◽  
D. Poppi ◽  
R. L. Coop ◽  
J. C. MacRae ◽  
...  
Keyword(s):  
Small Intestine ◽  
Food Intake ◽  
Transit Time ◽  
Gastrointestinal Motility ◽  
Subclinical Infection ◽  
Intestinal Transit Time ◽  
Small Intestinal Transit ◽  
Proximal Small Intestine ◽  
Small Intestinal ◽  
Small Intestinal Transit Time

The influence of a chronic subclinicael infection ofTrichostrongylus colubriformis, 2500 larvae/day for 12 weeks, on gastrointestinal motility and digesta flow was studied in 12 sheep suppliedad libitumwith food and water. Motility was recorded by X-radiography and electromyography from chronically implanted electrodes;abomasal volume and outflow were estimated by dilution of CrEDTA; small intestinal transit time was estimated by passage of Phenol Red. The findings were compared with measurements made prior to infection at restricted food intake and reported separately. The first effects of infection were seen after 3–4 weeks. No animal developed diarrhoea, but food intake was progressively reduced. Small intestinal transit time, abomasal volume and half-time of marker dilution increased while abomasal outflow decreased during infection. These changes occurred both in absolute terms and when compared with values predicted from the observed level of food intake. As the animals became resistant to the parasites abomasal volume and digesta flow returned towards control values (weeks 10–12). The migrating myoelectric complex (MMC) was disrupted in only one sheep, and only transiently. In all sheep the frequency of the MMC was increased during infection and there was a progressive inhibition of abomasal, duodenal and jejunal motility. X-radiography showed there was prolonged pooling of digesta in the proximal small intestine which was cleared only at the phase of regular spiking activity. Two sheep given an anthelmintic drench recovered normal motility and clearance of digesta. It is concluded that subclinical infection of sheep with T.colubriformisalters the normal pattern of gastrointestinal motility in the absence of any diarrhoea, and causes inhibition of abomasal and proximal small intestinal motility and digesta flow. The increased frequency of MMCs helps to maintain digesta flow through the proximal small intestine.

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