Intestinal distension alters vagal efferent activity and small intestinal transport in vivo

1993 ◽  
Vol 264 (2) ◽  
pp. G341-G350 ◽  
Author(s):  
X. Chu ◽  
X. Zhang ◽  
W. E. Renehan ◽  
W. H. Beierwaltes ◽  
R. Fogel
Keyword(s):  
Water Absorption ◽  
Neural Activity ◽  
Neural Circuit ◽  
Intestinal Transport ◽  
Intraluminal Pressure ◽  
Control Loop ◽  
Efferent Neurons ◽  
Intestinal Distension ◽  
Small Intestinal

We investigated whether intestinal distension altered net water absorption by an adjacent noncontiguous segment of intestine and the mechanism for this effect. Influx and efflux catheters were placed in two intestinal loops, after which the bowel was transected between the loops. During perfusion with Ringers-HCO3-, the proximal loop efflux catheter was elevated 5, 10, or 15 cm above the plane of the rat. Net water absorption was measured in the nondistended caudal (control) loop. Elevation of the proximal loop efflux catheter caused distension and increased intraluminal pressure in this loop but did not alter the circumference or intraluminal pressure of the caudal loop. Distension increased net water absorption by the caudal loop if the vagi were intact and the splanchnic nerves transected. Afferent vagotomy prevented the distension effect. Using the intracellular recording technique, we were able to show that the increase in absorption resulted from a reduction in the activity of vagal neurons innervating the gastrointestinal tract. Intestinal distension reduced the neural activity of 24 of 26 vagal efferent neurons. Our results demonstrate that after splanchnectomy intestinal distension activates a neural circuit that includes afferent and efferent vagal fibers, resulting in increased water absorption.

Intestinal filtration-secretion due to increased intraluminal pressure in rabbits

1982 ◽  
Vol 242 (1) ◽  
pp. G65-G75
Author(s):  
E. A. Swabb ◽  
R. A. Hynes ◽  
W. G. Marnane ◽  
J. S. McNeil ◽  
R. A. Decker ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
Surface Area ◽  
Intestinal Transport ◽  
Blood Flow Rate ◽  
Intraluminal Pressure ◽  
Rabbit Ileum ◽  
Venous Dilatation ◽  
Small Intestinal

The mechanism of changes in small intestinal transport due to acutely increased intraluminal hydrostatic pressure (IHP) was investigated in detail using perfused in vivo rabbit intestinal segments. IHP affected passive transport in vivo by increasing effective mucosal surface area in the small intestine (indicated by 3HOH transport and tissue architectural changes) and increasing small intestinal permeability (indicated by a proportionately greater increase in mannitol than erythritol secretory clearance). IHP did not alter ileal blood flow rate measured by radioactive microspheres, despite grossly evident venous dilatation, or active intestinal transport in the ileum as measured by a) in vitro ion transport in the absence of elevated hydrostatic pressure, b) mucosal adenylate cyclase or Na-K-ATPase activities, and c) glucose-stimulated water and electrolyte absorption. Acutely increased IHP appears to influence the hydrodynamics of the mucosal microcirculation in the rabbit ileum to produce a driving force for passive filtration-secretion, which is associated with and possibly augmented by increased tissue permeability and effective surface area.

Elevated intraluminal pressure alters rabbit small intestinal transport in vivo

1982 ◽  
Vol 242 (1) ◽  
pp. G58-G64 ◽  
Author(s):  
E. A. Swabb ◽  
R. A. Hynes ◽  
M. Donowitz
Keyword(s):  
Intestinal Transport ◽  
Intraluminal Pressure ◽  
Secretory Process ◽  
Test Segment ◽  
Marker Test ◽  
Control Segment ◽  
Small Intestinal ◽  
Induced Changes ◽  
Colonic Transport

The effect of acutely increased intraluminal hydrostatic pressure (IHP) on rabbit jejunal, ileal, and colonic water and electrolyte transport was determined in vivo in a distended test segment and adjacent control segment using a perfusion system with [14C]polyethylene glycol as a nonabsorbable marker. Test-segment IHP was increased by raising the efflux catheter to produce 10-70 cm water IHP, while control-segment IHP was held constant at 0 cm water. Acutely increased IHP up to 40 cm water in the jejunum and up to 30 cm water in the ileum caused decreased net absorption in the jejunum and net secretion in the ileum but caused no significant change in control-segment transport. This indicated that IHP-induced changes in transport were mediated by local rather than systemic effects. The IHP-induced secretory process was dependent on the magnitude of elevation in IHP and reversible at less than or equal to 20 cm water in the ileum. An IHP of 30 cm water was associated with nonreversible transport changes in the ileum. Acutely increased IHP to 70 cm water did not significantly alter colonic transport. This experimental model is suitable for a comprehensive investigation of the mechanism of IHP-induced changes in small intestinal transport.

Effect of absorption-modifying excipients, hypotonicity, and enteric neural activity in an in vivo model for small intestinal transport

2018 ◽  
Vol 549 (1-2) ◽  
pp. 239-248 ◽  
Author(s):  
D. Dahlgren ◽  
C. Roos ◽  
A. Lundqvist ◽  
C. Tannergren ◽  
M. Sjöblom ◽  
...  
Keyword(s):  
Neural Activity ◽  
Intestinal Transport ◽  
In Vivo Model ◽  
Small Intestinal

scholarly journals All-optical imaging and patterned stimulation with a one-photon endoscope

2021 ◽  
Author(s):  
Jinyong Zhang ◽  
Ryan N Hughes ◽  
Namsoo Kim ◽  
Isabella P Fallon ◽  
Konstantin I bakhurin ◽  
...  
Keyword(s):  
Neural Activity ◽  
Calcium Imaging ◽  
Neural Circuit ◽  
Integrated System ◽  
Striatal Neurons ◽  
Indirect Pathway ◽  
Cellular Resolution ◽  
All Optical ◽  
Freely Moving

While in vivo calcium imaging makes it possible to record activity in defined neuronal populations with cellular resolution, optogenetics allows selective manipulation of neural activity. Recently, these two tools have been combined to stimulate and record neural activity at the same time, but current approaches often rely on two-photon microscopes that are difficult to use in freely moving animals. To address these limitations, we have developed a new integrated system combining a one-photon endoscope and a digital micromirror device for simultaneous calcium imaging and precise optogenetic photo-stimulation with near cellular resolution (Miniscope with All-optical Patterned Stimulation and Imaging, MAPSI). Using this highly portable system in freely moving mice, we were able to image striatal neurons from either the direct pathway or the indirect pathway while simultaneously activating any neuron of choice in the field of view, or to synthesize arbitrary spatiotemporal patterns of photo-stimulation. We could also select neurons based on their relationship with behavior and recreate the behavior by mimicking the natural neural activity with photo-stimulation. MAPSI thus provides a powerful tool for interrogation of neural circuit function in freely moving animals.

Vagal control of fluid transport, transmural potential difference, and motility in the ferret jejunum

1985 ◽  
Vol 249 (6) ◽  
pp. G651-G654 ◽  
Author(s):  
B. Greenwood ◽  
N. W. Read
Keyword(s):  
Fluid Transport ◽  
Vagal Stimulation ◽  
Contractile Activity ◽  
Intestinal Transport ◽  
Intestinal Secretion ◽  
Potential Difference ◽  
Intraluminal Pressure ◽  
Jejunal Loop

The role of the vagus nerve in the control of intestinal transport was investigated in the ferret jejunum in vivo. Fluid transport was measured in an isolated 10-cm segment of jejunum by means of a single-pass perfusion technique with radioactive markers introduced into the perfusion fluid and the bloodstream of the animal. Transmural potential difference (PD) and intraluminal pressure in the perfused jejunal loop were also monitored. Vagal stimulation (20 Hz, 20 V, and 0.5 ms for 1 min) resulted in jejunal fluid movement in the direction of secretion, a rise in transmural PD, and an increase in jejunal contractile activity. Similar changes were induced by close intra-arterial injection of acetylcholine (20 micrograms X kg-1). The contractile response to vagal stimulation was abolished by atropine. Moreover, atropine did not block the changes in fluid transport and transmural PD that were induced by vagal stimulation, although the transmural PD response was reduced. The results suggest that vagal stimulation induces intestinal secretion accompanied by a rise in transmural PD; the events are mediated at least in part by a noncholinergic transmitter as yet undetermined.

Functional roles of capsaicin-sensitive intrinsic neural circuit in the regulation of esophageal peristalsis in rats: in vivo studies using a novel method

2014 ◽  
Vol 306 (9) ◽  
pp. G811-G818 ◽  
Author(s):  
Takeshi Shima ◽  
Takahiko Shiina ◽  
Kiyotada Naitou ◽  
Hiroyuki Nakamori ◽  
Yasutake Shimizu
Keyword(s):  
Neural Circuit ◽  
Vagal Afferents ◽  
Intraluminal Pressure ◽  
Liquid Volume ◽  
Esophageal Peristalsis ◽  
Functional Roles ◽  
Pressure Threshold ◽  
Novel Method ◽  
Intrinsic Neurons

A well-developed myenteric plexus exists in the esophagus composed of striated muscle layers, but its functional role in controlling peristaltic movements remains to be clarified. The purpose of this study was to clarify the role of a local neural reflex consisting of capsaicin-sensitive primary afferent neurons and intrinsic neurons in esophageal peristalsis. We firstly devised a method to measure peristaltic movement of esophagus in vivo in rats. Rats were anesthetized with urethane, and esophageal intraluminal pressure and propelled intraluminal liquid volume were recorded. In the experimental system, an intraluminal pressure stimulus evoked periodic changes in intraluminal pressure of the esophagus, which were consistently accompanied by intraluminal liquid propulsion. Bilateral vagotomy abolished changes in intraluminal pressure as well as liquid propulsion. These results indicate that the novel method is appropriate for inducing peristalsis in the esophagus composed of striated muscles. Then, by using the method, we examined functional roles of the local reflex in esophageal peristalsis. For that purpose, we used rats in which capsaicin-sensitive neurons had been destroyed. The esophagus of capsaicin-treated rats showed a multiphasic rise in intraluminal pressure, which may due to noncoordinated contractions of esophageal muscles, whereas a monophasic response was observed in the intact rat esophagus. In addition, destruction of capsaicin-sensitive neurons increased the propelled liquid volume and lowered the pressure threshold for initiating peristalsis. These results suggest that the local neural reflex consisting of capsaicin-sensitive neurons and intrinsic neurons contributes to coordination of peristalsis and suppresses mechanosensory function of vagal afferents in the esophagus.

Anion effects on fluid absorption from rat jejunum perfused in vivo

1983 ◽  
Vol 244 (1) ◽  
pp. G33-G39
Author(s):  
M. H. Humphreys ◽  
L. Y. Chou
Keyword(s):  
Atpase Activity ◽  
Water Absorption ◽  
Brush Border ◽  
Intestinal Transport ◽  
Ringer Solution ◽  
Rat Jejunum ◽  
Perfusion Fluid ◽  
Potent Effect

Perfusion of rat jejunal segments in vivo with an isotonic, HCO3-free SO4-Ringer solution resulted in low rates of net sodium (JNanet) and water absorption. When the perfusion fluid was changed to one containing 25 mM Na2SO3, JNanet increased from 4.7 +/- 1.2 to 11.6 +/- 1.5 (SE) mumol X cm-1 X h-1 (P less than 0.001). This increased absorption was accompanied by comparable increases in chloride and water absorption, occurred without a detectable change in potential difference across the perfused segment, and was readily reversed on reinstitution of perfusion with SO4-Ringer. Perfusion with SO3-Ringer had no effect on electrolyte absorption from terminal segments of rat ileum. Addition of L-phenylalanine stimulated absorption from SO4-Ringer perfusate but not from SO3-Ringer perfusate. Addition of 25 mM NaHCO3 to SO4-Ringer perfusate caused parallel increases in JNanet and JHCO3net; when 25 mM NaHCO3 was added to SO4-Ringer perfusate that also contained 25 mM NaSCN, the same increase in JHCO3net occurred but was not associated with any increase in JNanet. These results indicate a potent effect of SO2-3 and HCO-3 to stimulate JNanet from rat jejunum but not from ileum. These anion effects on intestinal transport in vivo resemble their effects on ATPase activity of brush-border fractions from small intestine in vitro and raise the possibility that these effects on ion transport could be mediated through the changes in brush-border ATPase activity, which are brought about by exposure to these anions, although other explanations are also possible.

Disruption of intestinal barrier function associated with experimental colitis: possible role of mast cells

1998 ◽  
Vol 274 (1) ◽  
pp. G203-G209 ◽  
Author(s):  
Jürgen Stein ◽  
Jürgen Ries ◽  
Kim E. Barrett
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Water Absorption ◽  
Water Flux ◽  
Intestinal Barrier ◽  
Intestinal Transport ◽  
Experimental Colitis ◽  
Intestinal Barrier Function ◽  
Trinitrobenzenesulfonic Acid

The objective was to characterize changes in barrier and transport function in an experimental model of colitis, and to determine whether mast cells contribute to these changes. Colitis was induced in rats with intracolonic 2,4,6-trinitrobenzenesulfonic acid (TNBS, 30 mg) in 50% ethanol. Controls received 0.9% saline or the ethanol vehicle alone. In vivo loop perfusion was used to assess colonic water flux (in μl ⋅ cm−1 ⋅ h−1) and lumen-to-blood 51Cr-labeled EDTA clearance (% administered dose) after TNBS. Myeloperoxidase (MPO) was used as an index of granulocyte influx. TNBS or its vehicle caused a marked decrease in water absorption and an increase in permeability at 4 h after administration compared with saline. Neither dexamethasone (anti-inflammatory control) nor doxantrazole (mast cell stabilizer) was able to attenuate these early changes likely caused by the vehicle. In contrast, at later times, TNBS (but not its vehicle) also increased51Cr-EDTA permeability and decreased water absorption; both effects were significantly attenuated by dexamethasone or doxantrazole. These drugs also significantly reduced TNBS-induced MPO accumulation and release of rat mast cell protease II. We conclude that experimental colitis is associated with severe defects in intestinal transport and barrier functions and that mast cells may contribute to the pathogenesis of these changes.

scholarly journals Porcine small intestinal organoids as a model to explore ETEC–host interactions in the gut

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Bjarne Vermeire ◽  
Liara M. Gonzalez ◽  
Robert J. J. Jansens ◽  
Eric Cox ◽  
Bert Devriendt
Keyword(s):  
Intestinal Epithelial ◽  
Gut Health ◽  
Functional Responses ◽  
Host Pathogen Interactions ◽  
Epithelial Surface ◽  
Host Interactions ◽  
Intestinal Organoids ◽  
Host Pathogen ◽  
Small Intestinal

AbstractSmall intestinal organoids, or enteroids, represent a valuable model to study host–pathogen interactions at the intestinal epithelial surface. Much research has been done on murine and human enteroids, however only a handful studies evaluated the development of enteroids in other species. Porcine enteroid cultures have been described, but little is known about their functional responses to specific pathogens or their associated virulence factors. Here, we report that porcine enteroids respond in a similar manner as in vivo gut tissues to enterotoxins derived from enterotoxigenic Escherichia coli, an enteric pathogen causing postweaning diarrhoea in piglets. Upon enterotoxin stimulation, these enteroids not only display a dysregulated electrolyte and water balance as shown by their swelling, but also secrete inflammation markers. Porcine enteroids grown as a 2D-monolayer supported the adhesion of an F4+ ETEC strain. Hence, these enteroids closely mimic in vivo intestinal epithelial responses to gut pathogens and are a promising model to study host–pathogen interactions in the pig gut. Insights obtained with this model might accelerate the design of veterinary therapeutics aimed at improving gut health.

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