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.

Uncertainty in the diagnosis of cystic fibrosis: Possible role of in vivo nasal potential difference measurements

1998 ◽  
Vol 132 (4) ◽  
pp. 596-599 ◽  
Author(s):  
David C. Wilson ◽  
Lynda Ellis ◽  
Julian Zielenski ◽  
Mary Corey ◽  
Wan F. Ip ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Potential Difference ◽  
Nasal Potential Difference

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.

Influence of vascular and luminal hexoses on rat intestinal basolateral glucose transport

1994 ◽  
Vol 72 (4) ◽  
pp. 317-326 ◽  
Author(s):  
Raymond Tsang ◽  
Ziliang Ao ◽  
Chris Cheeseman
Keyword(s):  
Glucose Transport ◽  
Plasma Glucose ◽  
Intestinal Adaptation ◽  
Basolateral Membrane ◽  
Physiological Role ◽  
Intestinal Transport ◽  
Membrane Vesicles ◽  
Luminal Perfusion

The influence of luminal and vascular hexoses in rats on glucose transport across the jejunal basolateral membrane (BLM) was measured using isolated membrane vesicles prepared from infused animals. In vivo vascular infusions of glucose produced an increase in glucose transport across BLM vesicles. Sucrose, mannose, galactose, and fructose had no significant effect. Plasma glucose concentrations were unaffected by galactose and sucrose vascular infusions, while mannose and fructose produced a modest rise, and glucose increased plasma glucose to 20 mM. Insulin release was significantly increased by vascular infusion of glucose and fructose, while mannose produced only a small sustained rise. Sucrose and galactose had no effect. Perfusion through the lumen of the rat jejunum in vivo, for up to 4 h, with glucose, fructose, sucrose, or lactate (100 or 25 mM) produced a significant increase in the maximal rate of glucose transport (up to 4- to 5-fold) across BLMs. Galactose and mannose had no effect. Luminal glucose perfusion produced a small nonsignificant increase in glucose inhibitable cytochalasin B binding to BLM vesicles, and no change was seen in the microsomal pool of binding sites. The abundance of GLUT2 in the jejunal BLM, as determined by Western blotting, was unaffected by luminal perfusion of 100 mM glucose for 4 h. Fructose almost completely inhibited the carrier-mediated uptake of glucose in control and upregulated jejunal BLM vesicles. These results are discussed in relation to the physiological role of the upregulation of GLUT2 activity by luminal and vascular hexoses.Key words: intestinal transport, basolateral membrane, glucose transport, intestinal adaptation.

scholarly journals Is apolipoprotein A-IV rate limiting in the intestinal transport and absorption of triglyceride?

2013 ◽  
Vol 304 (12) ◽  
pp. G1128-G1135 ◽  
Author(s):  
Alison B. Kohan ◽  
Fei Wang ◽  
Xiaoming Li ◽  
Abbey E. Vandersall ◽  
Sarah Huesman ◽  
...  
Keyword(s):  
Intestinal Mucosa ◽  
Dietary Fat ◽  
Intestinal Transport ◽  
Dietary Lipid ◽  
Lipid Absorption ◽  
Lymphatic Transport ◽  
Apolipoprotein A ◽  
Rate Limiting

Apolipoprotein A-IV (apoA-IV) is synthesized by the intestine and secreted when dietary fat is absorbed and transported into lymph associated with chylomicrons. We have recently demonstrated that loss of apoA-IV increases chylomicron size and delays its clearance from the blood. There is still uncertainty, however, about the precise role of apoA-IV on the transport of dietary fat from the intestine into the lymph. ApoA-IV knockout (KO) mice do not have a gross defect in dietary lipid absorption, as measured by oral fat tolerance and fecal fat measurements. Here, using the in vivo lymph fistula mouse model, we show that the cumulative secretion of triglyceride (TG) into lymph in apoA-IV KO mice is very similar to that of wild-type (WT) mice. However, the apoA-IV KO mice do have subtle changes in TG accumulation in the intestinal mucosa during a 6-h continuous, but not bolus, infusion of lipid. There are no changes in the ratio of esterified to free fatty acids in the intestinal mucosa of the apoA-IV KO, however. When we extended these findings, by giving a higher dose of lipid (6 μmol/h) and for a longer infusion period (8 h), we found no effect of apoA-IV KO on intestinal TG absorption. This higher lipid infusion most certainly stresses the intestine, as we see a drastically lower absorption of TG (in both WT and KO mice); however, the loss of A-IV does not exacerbate this effect. This supports our hypothesis that apoA-IV is not required for TG absorption in the intestine. Our data suggest that the mechanisms by which the apoA-IV KO intestine responds to intestinal lipid may not be different from their WT counterparts. We conclude that apoA-IV is not required for normal lymphatic transport of TG.

Antegrade and retrograde fluid transport through the vas deferens

1995 ◽  
Vol 269 (5) ◽  
pp. R1197-R1203
Author(s):  
K. Kihara ◽  
K. Sato ◽  
M. Ando ◽  
H. Azuma ◽  
H. Oshima
Keyword(s):  
Fluid Transport ◽  
Vas Deferens ◽  
Ejaculatory Duct ◽  
Intraluminal Pressure ◽  
Muscle Tonus ◽  
Sperm Transport ◽  
Mode Of Transport ◽  
Seminal Emission ◽  
Stimulation Of

Intraluminal pressure of the seminal tract at seminal emission from the ejaculatory duct and the mode of transport of cauda epididymal contents were investigated to explore the mechanism of sperm transport. Direct electrical stimulation of any site of the cauda epididymis and vas deferens, which generated nerve-transmitted muscle contraction, caused elevation of the intraluminal pressure only at the cauda epididymis, whereas stimulation of the testis, caput, and corpus epididymis caused no response. The dye instilled in the cauda was emitted into the urethra during the stimulation. Shortly after discontinuation of the stimulation, retrograde movement of residual dye in the vas resulted in its ultimate reentry into the cauda epididymis. Significant decrease of the muscle tonus just after contraction was observed at the cauda. Distension of the wall of the vas generated elevation of the intraluminal pressure only at the site distended. The above results indicate the presence of rapid antegrade and retrograde movement of the sperm and the crucial role of the cauda epididymis on the sperm transport.

Effect of serotonin treatment on intestinal transport in the rabbit.

1977 ◽  
Vol 232 (1) ◽  
pp. E85 ◽  
Author(s):  
M Donowitz ◽  
A N Charney ◽  
J M Heffernan
Keyword(s):  
Amino Acid ◽  
Adenylate Cyclase ◽  
Carcinoid Syndrome ◽  
Intestinal Transport ◽  
Intestinal Secretion ◽  
Serotonin Level ◽  
Proximal Jejunum ◽  
Intestinal Histology ◽  
Perfusion Technique

The hormone serotonin (5-hydroxytryptamine) has been implicated as the cause of the diarrhea seen in many patients with the carcinoid syndrome. To determine whether serotonin is an intestinal secretagogue, the effect of serotonin on intestinal water and electrolyte transport was evaluated in the rabbit. Two weeks of daily subcutaneous injection of serotonin suspended in oil resulted in a blood serotonin level elevated to twice that of controls. Intestinal transport was studied in vivo by a perfusion technique. Serotonin treatment resulted in ileal secretion and decreased mid-jejunal absorption of water and electrolytes but did not effect water absorption in the proximal jejunum or colon. Intestinal absorption of D-glucose and the amino acid L-tryptophan and glucose-dependent water and electrolyte absorption were normal in serotonin-treated animals. Serotonin-induced ileal secretion was reversed by methysergide, a peripheral antagonist of serotonin action. No alterations in intestinal histology or permeability occurred in serotonin-treated animals. Serotonin-induced intestinal secretion was not associated with alterations in the activities of intestinal mucosal adenylate cyclase, cyclic nucleotide phosphodiesterase, or Na-K-ATPase.

Optoelectronic transducer for in vivo recording of oviductal contractile activity

1980 ◽  
Vol 239 (3) ◽  
pp. R326-R331
Author(s):  
S. A. Halbert ◽  
R. J. Bourdage ◽  
J. L. Boling ◽  
J. A. Ringo ◽  
R. J. Blandau
Keyword(s):  
Contractile Activity ◽  
Red Light ◽  
Muscular Activity ◽  
Optical Signal ◽  
In Vivo Experiments ◽  
Optoelectronic Transducer ◽  
Optical Analog

An optoelectronic instrument to record oviductal muscular activity in chronically instrumented animals was evaluated in in vitro and in vivo experiments. The intensity of red light transmitted through the oviduct was modulated by contractions of the oviductal wall producing an optical analog of the mechanical events. Accuracy of the analog was tested by Fourier analysis of signals from mechanical and optoelectronic transducers placed at the same site on the oviduct; the results validated the use of the optical device as a contraction event sensor. Contractions of the tubal mesenteries had less effect on the optical signal than on signals from extraluminal mechanical transducers. Optical and photographic recordings of luminal transport in exposed oviducts showed a correspondence of intraluminal movements to events in the optical contraction signal. This instrument does not alter tubal function, and thus it is an especially useful experimental tool to investigate the role of oviductal muscular activity in fertility.

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.

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