scholarly journals Characteristics of Sodium Flux from Serosa to Mucosa in Rabbit Ileum

1974 ◽  
Vol 64 (3) ◽  
pp. 274-292 ◽  
Author(s):  
Jehan-F. Desjeux ◽  
Y.-H. Tai ◽  
Peter F. Curran
Keyword(s):  
Electrical Potential ◽  
Secretory Process ◽  
Rabbit Ileum ◽  
Shunt Pathway ◽  
Diffusional Flux ◽  
Transcellular Pathway ◽  
Sodium Flux ◽  
Secretory Transport ◽  
Paracellular Shunt

Sodium flux from serosa to mucosa, JsmNa in rabbit ileum in vitro has been studied as a function of applied electrical potential at equal sodium concentrations in the bathing solutions. The results indicate that JsmNa involves two pathways, a diffusional flux through a paracellular shunt pathway and a flux that is independent of applied potential and presumably involves a transcellular pathway. The latter pathway comprises approximately 25 % of JsmNa in Ringer's solution containing 10 mM glucose and 25 mM bicarbonate. It is stimulated significantly by theophylline unaffected by removal of glucose or addition of ouabain but is reduced to negligible values by anoxia, dinitrophenol, and replacement of all chloride and bicarbonate by isethionate. Thus this component of JsmNa has a number of characteristics consistent with involvement in a specific secretory process mediating an electrically neutral secretory transport of sodium plus anion from serosa to mucosa. In addition to stimulating this process, theophylline significantly reduced the permeability of the paracellular shunt pathway to sodium.

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.

Intra- and extracellular gradients of electrical potential and ion activities of the epithelial cells of the rabbit ileum in vivo recorded by microelectrodes

1975 ◽  
Vol 271 (912) ◽  
pp. 277-281 ◽  
Keyword(s):  
Epithelial Cells ◽  
Electrical Potential ◽  
The State ◽  
Low Oxygen ◽  
Rabbit Ileum ◽  
Experimental Conditions ◽  
Ussing Chambers ◽  
Ion Activities

The epithelial cells of the rabbit ileum are about 40 µm long and have a diameter of roughly 5 µm. They are closely packed in a columnar fashion with their mucosal ends facing the lumen of the intestine and their serosal ends abutting the basement membrane and facing the underlying capillaries, lymphatics and connective tissue. The inner wall of the intestine is coated with a layer of mucopolysacharides, the mucus layer. When Krebs solution or similar solutions are placed in the lumen it is well known (e.g. the review by Edmonds 1970) that the solution is transported into the underlying tissues. During this transport the sodium activity in the gut lumen remains constant, the chloride activity decreases and the bicarbonate activity increases. However, the relationship of the intra- to the extracellular environment of each individual cell during this transport is only little understood. In recent years the methods applied in the study of the state of the cells during this transport have mostly been of a type that requires preparation of the tissue in vitro , e.g. usage of flamephotometry and Ussing-chambers. In case of the intestine of warm-blooded animals such a choice of experimental conditions is unfortunate for several reasons: ( a ) The transport is no longer into the blood or lymphatic drainage, ( b ) the epithelial cells have to be oxygenated from their luminal ends which in vivo are normally at a very low oxygen concentration (Crompton, Silver & Shrimpton 1965) and ( c ) in some experiments the physiological parameters of the tissue change during the experiment (e.g. Powell, Binder & Curran 1973). However, the use of microelectrodes allows an in vivo approach since the tissue can be left in its natural environment during the measurements. Furthermore liquid ion exchanges and ion-sensitive glasses developed over the past few years have led to the construction of microelectrodes selective to various ions (Hinke 1959; Thomas 1970; Walker 1971), so that the state of cells in terms of intra- and extracellular electrical potential and ion activities can be determined. Thus intracellular sodium and potassium has been recorded in the epithelial cells of the bullfrog small intestine in vitro (Lee & Armstrong 1972). The purpose of this work was first to construct an in vivo model in which the epithelial cell layer of the rabbit ileum could be studied by microelectrodes and secondly to determine the intra and extracellular electrical potential and ion activities in these cells when the lumen of the intestine was filled with various salt solutions.

Effects of methylprednisolone on electrolyte transport by in vitro rat ileum

1981 ◽  
Vol 240 (5) ◽  
pp. G365-G370 ◽  
Author(s):  
Y. H. Tai ◽  
R. A. Decker ◽  
W. G. Marnane ◽  
A. N. Charney ◽  
M. Donowitz
Keyword(s):  
Atpase Activity ◽  
Guanylate Cyclase ◽  
Short Circuit ◽  
Electrical Potential ◽  
Cyclase Activity ◽  
Secretory Process ◽  
Electrical Potential Difference ◽  
Guanylate Cyclase Activity ◽  
Cl Secretion

Administration of the glucocorticoid methylprednisolone (MP) (30 mg/kg body wt for 3 days) to rats increased intestinal mucosal guanylate cyclase and Na-K-ATPase activities, short-circuit current (Isc), electrical potential difference (PD), net Na absorption, and net Cl secretion and reversed HCO3 transport from secretion to absorption. In the MP-treated animals, removal of HCO3 from both the mucosal and serosal bathing solutions increased Cl secretion but did not alter the Isc, PD, and net Na flux. Removal of Cl abolished the MP-induced increase in Isc but did not affect the MP-induced changes in net Na and HCO3 fluxes. At 6 h, after a single dose of MP, stimulation of guanylate cyclase activity was already maximal, whereas Na-K-ATPase activity was not detectably altered. The changes in intestinal transport properties present 6 h after MP treatment and associated with the increased guanylate cyclase activity were an increase in Isc and PD and a reversal of net Cl absorption to net secretion. These results suggest that an initial response to MP administration is a persistent increase in intestinal guanylate cyclase activity that mediates an electrogenic Cl secretory process, then is followed by a superimposed effect of increased Na-K-ATPase activity that mediates an increase in net Na absorption.

Effects of sulfodeoxycholate on rat and rabbit small intestine

1985 ◽  
Vol 248 (4) ◽  
pp. G485-G493 ◽  
Author(s):  
H. V. Ammon ◽  
E. J. Tapper ◽  
R. A. Komorowski ◽  
U. K. Charaf ◽  
R. F. Loeffler ◽  
...  
Keyword(s):  
Bile Acids ◽  
High Performance ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Biological Properties ◽  
Reversed Phase ◽  
Rabbit Ileum ◽  
Mucosal Permeability ◽  
Sodium Flux

To determine how sulfation alters the biological properties of dihydroxy bile acids, we compared the effects of 3-sulfodeoxycholate (SDC) and deoxycholate (DC) in the rat and rabbit intestine. While 5 mM DC induced water and electrolyte secretion and inhibited glucose absorption in the rat, SDC enhanced jejunal and ileal water and solute absorption. SDC had no effect in the rabbit ileum. In the rat jejunum DC caused mucosal injury and enhanced mucosal permeability while SDC had no effect. In vitro in the rabbit ileum, 10 mM SDC enhanced net sodium flux and decreased net residual flux, while 0.5 mM DC reduced net sodium flux and induced Cl- secretion. Both bile acids increased short-circuit current and potential difference and decreased tissue conductance. During reversed-phase, high-performance liquid chromatography SDC was more polar than DC. Sulfation reduced the ability of DC to destroy large unilamellar liposomes by a factor of 10. Thus, sulfation abolishes the effects of DC on the intestine by enhancing the polarity of this molecule. The enhancement of intestinal solute and water absorption by SDC requires further study.

Effect of veratrine and 50 mM K on ileal transport and electrically induced secretion

1981 ◽  
Vol 240 (3) ◽  
pp. G211-G216
Author(s):  
K. A. Hubel
Keyword(s):  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Electrical Field Stimulation ◽  
Electrical Potential Difference ◽  
Apud Cells ◽  
Rabbit Ileum ◽  
Cl Secretion ◽  
Ionic Fluxes

To obtain additional evidence that the Cl secretion caused by electrical field stimulation (EFS) in rabbit ileum in vitro is mediated by nerves or amine precursor uptake and decarboxylation (APUD) cells, we determined whether the response could be prevented by agents that depolarize nerves, veratrine or 50 mM K. EFS 1) increased transmural electrical potential difference (PD) and the short-circuit current (Isc) and reduced total ion conductivity (G), 2) caused Cl secretion by reducing the mucosal-to-serosal flow of chloride (JClm leads to s) alone or in combination with an increase in the serosal-to-mucosal flux of chloride (JCls leads to m), and 3) reduced Na absorption or caused secretion by increasing JCls leads to m alone or in association with a reduction in JNam leads to s. At 10(-5) g/ml, veratrine prevented the changes in ionic fluxes caused by EFS and reduced the PD and Isc. It did not reduce the Isc response to 5 mM aminophylline, however. Fifty millimolar K decreased PD and Isc and increased G. JNam leads to s and JNas leads to m diminished in proportion to the reduction in bath Na concentration, so the net flux of sodium (JNanet) was not affected. JClnet did not change, although both JClm leads to s and JCls leads to m increased. Fifty millimolar K prevented the changes in ionic fluxes caused by EFS and reduced the Isc response to aminophylline by half. The study provides additional evidence that the effects of EFS are mediated by nerves or electrically excitable APUD cells, but the contribution of each is uncertain.

scholarly journals Sodium chloride transport by rabbit gallbladder. Direct evidence for a coupled NaCl influx process.

1975 ◽  
Vol 65 (6) ◽  
pp. 769-795 ◽  
Author(s):  
R A Frizzell ◽  
M C Dugas ◽  
S G Schultz
Keyword(s):  
Chloride Transport ◽  
Electrical Potential ◽  
Potential Gradient ◽  
Adenosine Monophosphate ◽  
Electrochemical Potential ◽  
Rabbit Ileum ◽  
Nacl Transport ◽  
Basolateral Membranes ◽  
Rabbit Gallbladder

The results of the present study that NaCl transport by in vitro rabbit gallbladder must be a consequence of a neutral coupled carrier-mediated mechanism that ultimately results in the active absorption of both ions; pure electrical coupling between the movements of Na and Cl can be excluded on the grounds of electrphysiologic considerations. Studies on the unidirectional influxes of Na and Cl have localized the site of this coupled mechanism to the mucosal membranes. Studies on the intracellular ion concentrations and the intracellular electrical potential are consistent with the notion that (a) the coupled NaCl influx process results in the movement of Cl from the mucosal solution into the cell against an apparent electrochemical potential difference; (b) the energy for the uphill movement of Cl is derived from the Na gradient across the mucosal membrane which is maintained by an active Na extrusion mechanism located at the basolateral membranes; and (c) Cl exit from the cell across the basolateral membranes is directed down an electrochemical potential gradient and may be diffusional. Finally, as for the case of rabbit ileum, the coupled NaCl influx process is inhibited by elevated intracellular levels of cyclic 3',5'-adenosine monophosphate. A working model for transcellular and paracellular NaCl transport by in vitro rabbit gallbladder is proposed.

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

OSMOTIC INHIBITION OF THE NATRIFERIC RESPONSE OF THE TOAD URINARY BLADDER TO VASOPRESSIN

1975 ◽  
Vol 67 (1) ◽  
pp. 119-125
Author(s):  
P. J. BENTLEY
Keyword(s):  
Urinary Bladder ◽  
Water Movement ◽  
Short Circuit ◽  
Electrical Potential ◽  
Short Circuit Current ◽  
Toad Bladder ◽  
Toad Urinary Bladder ◽  
Electrical Potential Difference ◽  
Osmotic Gradient

SUMMARY The electrical potential difference and short-circuit current (scc, reflecting active transmural sodium transport) across the toad urinary bladder in vitro was unaffected by the presence of hypo-osmotic solutions bathing the mucosal (urinary) surface, providing that the transmural flow of water was small. Vasopressin increased the scc across the toad bladder (the natriferic response), but this stimulation was considerably reduced in the presence of a hypo-osmotic solution on the mucosal side, conditions under which water transfer across the membrane was also increased. This inhibition of the natriferic response did not depend on the direction of the water movement, for if the osmotic gradient was the opposite way to that which normally occurs, the response to vasopressin was still reduced. The natriferic response to cyclic AMP was also inhibited in the presence of an osmotic gradient. Aldosterone increased the scc and Na+ transport across the toad bladder but this response was not changed when an osmotic gradient was present. The physiological implications of these observations and the possible mechanisms involved are discussed.

scholarly journals Amorphous–Crystalline Calcium Phosphate Coating Promotes In Vitro Growth of Tumor-Derived Jurkat T Cells Activated by Anti-CD2/CD3/CD28 Antibodies

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3693
Author(s):  
Yurii P. Sharkeev ◽  
Ekaterina G. Komarova ◽  
Valentina V. Chebodaeva ◽  
Mariya B. Sedelnikova ◽  
Aleksandr M. Zakharenko ◽  
...  
Keyword(s):  
T Cells ◽  
Calcium Phosphate ◽  
Biological Effects ◽  
Electrical Potential ◽  
Biological Properties ◽  
Modern Trend ◽  
Calcium Phosphate Coating ◽  
Jurkat T Cells ◽  
Micro Arc Oxidation

A modern trend in traumatology, orthopedics, and implantology is the development of materials and coatings with an amorphous–crystalline structure that exhibits excellent biocopatibility. The structure and physico–chemical and biological properties of calcium phosphate (CaP) coatings deposited on Ti plates using the micro-arc oxidation (MAO) method under different voltages (200, 250, and 300 V) were studied. Amorphous, nanocrystalline, and microcrystalline statesof CaHPO4 and β-Ca2P2O7were observed in the coatings using TEM and XRD. The increase in MAO voltage resulted in augmentation of the surface roughness Ra from 2.5 to 6.5 µm, mass from 10 to 25 mg, thickness from 50 to 105 µm, and Ca/P ratio from 0.3 to 0.6. The electrical potential (EP) of the CaP coatings changed from −456 to −535 mV, while the zeta potential (ZP) decreased from −53 to −40 mV following an increase in the values of the MAO voltage. Numerous correlations of physical and chemical indices of CaP coatings were estimated. A decrease in the ZP magnitudes of CaP coatings deposited at 200–250 V was strongly associated with elevated hTERT expression in tumor-derived Jurkat T cells preliminarily activated with anti-CD2/CD3/CD28 antibodies and then contacted in vitro with CaP-coated samples for 14 days. In turn, in vitro survival of CD4+ subsets was enhanced, with proinflammatory cytokine secretion of activated Jurkat T cells. Thus, the applied MAO voltage allowed the regulation of the physicochemical properties of amorphous–crystalline CaP-coatings on Ti substrates to a certain extent. This method may be used as a technological mechanism to trigger the behavior of cells through contact with micro-arc CaP coatings. The possible role of negative ZP and Ca2+ as effectors of the biological effects of amorphous–crystalline CaP coatings is discussed. Micro-arc CaP coatings should be carefully tested to determine their suitability for use in patients with chronic lymphoid malignancies.

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