Impairment of contractility in vitro with abnormal mitochondrial response in rabbit ileum (IL) and colon (CO) after anastomosis

2001 ◽  
Vol 120 (5) ◽  
pp. A225-A225
Author(s):  
P PORTINCASA ◽  
M TESTINI ◽  
S SCACCO ◽  
G PICCINNI ◽  
F MINERVA ◽  
...  
Keyword(s):  
Rabbit Ileum

Chloroquine stimulates absorption and inhibits secretion of ileal water and electrolytes

1982 ◽  
Vol 243 (2) ◽  
pp. G117-G126
Author(s):  
R. Fogel ◽  
G. W. Sharp ◽  
M. Donowitz
Keyword(s):  
Cholera Toxin ◽  
Calcium Content ◽  
Intracellular Camp ◽  
Rabbit Ileum ◽  
Camp Content ◽  
Serosal Surface ◽  
Ileal Absorption ◽  
Camp Levels

The effects of chloroquine diphosphate, a drug with "'membrane-stabilizing" properties, were studied on basal ileal absorption and on ileal secretion induced by increased intracellular cAMP levels and calcium (serotonin). The studies were performed on rat (in vivo) and rabbit ileum (in vitro). Intraluminal chloroquine (10(-4) M) reversed cholera toxin- and theophylline-induced secretion in rat ileum but did not alter the cholera toxin- and theophylline-induced increases in cAMP content. Addition of chloroquine (10(-4) M) to the mucosal surface of rabbit ileum did not alter basal active electrolyte transport or the serotonin-induced decreased Na and Cl absorption but inhibited the theophylline-induced C1 secretion. Addition of chloroquine (10(-4)) M) to the serosal surface stimulated net Na and Cl absorption. This effect may involve intracellular calcium. Chloroquine increased the rabbit ileal calcium content and decreased 45Ca2+ influx from the serosal surface. Both the mucosal and serosal effects of chloroquine described led to a net increase in absorptive function of the intestine and should prove useful in developing treatment of diarrheal diseases.

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.

In vitro evidence that rabbit distal colonic muscularis mucosae has aClostridium difficiletoxin A receptor

1998 ◽  
Vol 275 (3) ◽  
pp. G402-G409 ◽  
Author(s):  
W. H. Percy ◽  
R. Burakoff ◽  
K. Rose ◽  
H. P. Desai ◽  
C. Pothoulakis ◽  
...  
Keyword(s):  
Circular Muscle ◽  
In Vitro Study ◽  
Mucosal Damage ◽  
Myoelectric Activity ◽  
Muscularis Mucosae ◽  
Rabbit Ileum ◽  
Toxin A ◽  
Initial Exposure ◽  
Motor Effects

In the rabbit ileum Clostridium difficile toxin A causes inflammation and mucosal damage via a specific glycoprotein receptor that contains α-d-galactose. In rabbit colon toxin A also causes inflammation, and this is associated with increased myoelectric activity and eicosanoid production. The present in vitro study was undertaken to determine if a toxin A receptor on one or more layers of colonic smooth muscle could mediate the motor effects of this agent. Toxin A (20–100 μg/ml) was without effect on longitudinal and circular muscle but had two different effects on the muscularis mucosae. Initial exposure to the toxin caused increased numbers of spontaneous contractions and a small, atropine-, tetrodotoxin-, and indomethacin-resistant increase in resting tone. More importantly, however, 30-min exposure to toxin A resulted in attenuated muscularis mucosae responses to acetylcholine and K+. Both the small excitatory and the larger inhibitory effects of toxin A were abolished by pretreatment with the lectin BS-1, which binds to toxin A receptors, but not by the nonreceptor-binding lectin DBA. These data strongly suggest that toxin A causes significant motor effects on the distal colonic muscularis mucosae via a receptor-mediated mechanism. These mechanical data were supported by the presence of histologically demonstrable toxin A and BS-1 binding sites on the muscularis mucosae but not on either the longitudinal or circular muscle layers, both of which were unresponsive to the toxin. By depressing muscularis mucosae function and, ultimately, mucosal movement as a result of toxin A production, C. difficile may promote its own proliferation, thus further contributing to the development of antibiotic-associated colitis.

scholarly journals Effects of exogenous and endogenous opiate compounds on ion transport in rabbit ileum in vitro

1978 ◽  
Vol 74 (5) ◽  
pp. 1081 ◽  
Author(s):  
L.C. Racusen ◽  
H.J. Binder ◽  
J.W. Dobbins
Keyword(s):  
Ion Transport ◽  
Rabbit Ileum ◽  
Endogenous Opiate

Effect of acetazolamide on sodium and chloride transport by in vitro rabbit ileum

1975 ◽  
Vol 228 (6) ◽  
pp. 1808-1814 ◽  
Author(s):  
HN Nellans ◽  
RA Frizzell ◽  
SG Schultz
Keyword(s):  
Cyclic Amp ◽  
Chloride Transport ◽  
Short Circuit ◽  
Electrical Potential ◽  
Direct Interaction ◽  
Short Circuit Current ◽  
Electrical Potential Difference ◽  
Membrane Component ◽  
Rabbit Ileum

Acetazolamide (8 mM) aboishes active Cl absorption and inhibits but does not abolish active Na absorption by stripped, short-circuited rabbit ileum. These effects are not accompanied by significant changes in the transmural electrical potential difference or short-circuit current. Studies of the undirectional influxes of Na andCl indicate that acetazolamide inhibits the neutral, coupled NaCl influx process at the mucosal membranes. This action appears to explain the observed effect of acetazolamide on active, transepithelial Na and Cl transport. Acetazolamide did not significantly inhibit either spontaneous or theophylline-induced Cl secretion by this preparation, suggesting that the theophylline-induced secretion may not simply be due tothe unmasking of a preexisting efflux process when the neutral influx mechanism is inhibited by theophylline. Finally, inhibition of the neutral NaCl influx process by acetazolamide does not appear to be attributable to an inhibition of endogenous HCO3production or an elevation in intracellular cyclic-AMP levels. Instead, it appearstheat the effect of acetazolamide is due to a direct interaction with a membrane component involved in the coupled influx process.

An Investigation of the Role of Possible Neural Mechanisms in Cholera Toxin-Induced Secretion in Rabbit Ileal Mucosa in Vitro

1989 ◽  
Vol 77 (2) ◽  
pp. 161-166 ◽  
Author(s):  
K. J. Moriarty ◽  
N. B. Higgs ◽  
M. Woodford ◽  
L. A. Turnberg
Keyword(s):  
Cholera Toxin ◽  
Fluid Transport ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Electrical Potential Difference ◽  
Rabbit Ileum ◽  
Ileal Mucosa

1. Cholera toxin stimulates intestinal secretion in vitro by activation of mucosal adenylate cyclase. However, it has been proposed that cholera toxin promotes secretion in vivo mainly through an indirect mechanism involving enteric neural reflexes. 2. We examined this hypothesis further by studying the influence of neuronal blockade on cholera toxin-induced changes in fluid transport across rabbit ileum in vitro. Mucosa, stripped of muscle layers, was mounted in flux chambers and luminal application of crude cholera toxin (2 μg/ml) caused a delayed but sustained rise in the short-circuit current, electrical potential difference and Cl− secretion. Pretreatment with the nerve-blocking drug, tetrodotoxin (5 × 10−6 mol/l serosal side), failed to influence the secretory response to cholera toxin, and addition of tetrodotoxin at the peak response to cholera toxin also had no effect. 3. That tetrodotoxin could block neurally mediated secretagogues was confirmed by the demonstration that the electrical responses to neurotensin (10−7 mol/l and 10−8 mol/l) were blocked by tetrodotoxin (5 × 10−6 mol/l). Furthermore, the response to cholera toxin of segments of ileum, which included the myenteric, submucosal and mucosal nerve plexuses, was not inhibited by tetrodotoxin. 4. We conclude that cholera toxin-induced secretion in rabbit ileum in vitro is not mediated via a neurological mechanism.

Relationship between transmural potential difference and smooth muscle slow waves and contractility in the rabbit small intestine in vitro

1988 ◽  
Vol 66 (9) ◽  
pp. 1161-1165 ◽  
Author(s):  
Beverley Greenwood ◽  
Jan D. Huizinga ◽  
Edwin Chow ◽  
Wylie J. Dodds
Keyword(s):  
Smooth Muscle ◽  
Electrical Activity ◽  
Slow Wave ◽  
Muscle Activity ◽  
Slow Waves ◽  
Potential Difference ◽  
Intraluminal Pressure ◽  
Mechanical Activity ◽  
Rabbit Ileum

The relationship between transmural potential difference (PD) and smooth muscle electrical and mechanical activity was investigated in the rabbit ileum in vitro. Transmural PD was monitored using agar salt bridge electrodes connected via calomel half cells to an electrometer. Force displacement transducers recorded predominantly longitudinal smooth muscle activity. Concurrently, predominantly circular muscle activity was recorded at three sites using intraluminal pressure probes. At the same sites, suction electrodes monitored electrical activity of the smooth muscle. In all experiments, fluctuations in transmural PD were temporally linked to smooth muscle mechanical and electrical activity. The frequency of PD oscillations, electrical slow waves, and cyclic pressure changes were identical within each segment. Adrenaline abolished smooth muscle electrical spiking, all mechanical activity, and transmural fluctuations in PD. However, the slow waves were not abolished, though their frequency was increased. Phentolamine but not propranolol reversed the effects of adrenaline, thus slow wave frequency is influenced by α-adrenergic stimulation in the rabbit ileum. In conclusion, oscillations in transmural PD are unrelated to the ionic processes associated with the slow wave. However, they are in some way linked to smooth muscle contractile activity, possibly via an intrinsic neural mechanism as observed in the guinea pig.

Methylprednisolone increases absorptive capacity of rabbit ileum in vitro

1983 ◽  
Vol 245 (4) ◽  
pp. G562-G567 ◽  
Author(s):  
J. H. Sellin ◽  
R. C. DeSoignie
Keyword(s):  
Ion Transport ◽  
Absorptive Capacity ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Ion Flux ◽  
Rabbit Ileum ◽  
Transport Pathways ◽  
Na Pump ◽  
Intestinal Ion Transport

The effect of glucocorticoids on intestinal ion transport was studied in ileum in vitro from control and methylprednisolone (MP)-treated (40 mg im for 2 days) rabbits under the following conditions: a) basal rates of Na and Cl transport, b) the response to an individual absorptive stimulus (alanine, glucose, or epinephrine), and c) the response to a combination of the three absorptive stimuli. The results indicate that MP 1) increases basal absorption of Na and Cl and secretion of bicarbonate (as measured by residual ion flux), 2) does not alter the specific transport pathways stimulated by maximal doses of alanine, glucose, or epinephrine, but 3) significantly increases the absorptive capacity of ileum. After addition of combined alanine, glucose, and epinephrine, MP-treated ileum absorbed 15.8 mueq X cm-2 X h-1 Na (vs. 6.6 in controls, P less than 0.001) and 9.5 mueq X cm-2 X h-1 Cl (vs. 4.1 in controls, P less than 0.005). Additionally MP did not alter the Na dependence of either the short-circuit current or Cl absorption found in controls, although there appears to be a portion of residual ion flux insensitive to epinephrine inhibition. These data suggest that the MP-induced increase in absorptive capacity is due to an increase in a postapical transport step, most probably the Na pump.

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