Na+, Li+ and Cl− transport by brush border membranes from rabbit jejunum

Gunther, R D; Wright, Ernest M.

doi:10.1007/bf01870497

Cited by 75 publications

(28 citation statements)

References 21 publications

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“…These effects indicate that the Na+-H+ antiport is involved in H+ secretion across the brush-border membrane. The presence of the Na+-H+ antiport system in the intestinal brush-border membranes has been demonstrated by several authors (Murer, Hopfer & Kinne, 1976;Gunther & Wright, 1983;Cassano, Stieger & Murer, 1984).…”

Section: Discussionmentioning

confidence: 99%

Factors affecting the microclimate pH in rat jejunum.

Shimada

1987

The Journal of Physiology

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SUMMARY1. Single-barrelled pH-sensitive microelectrodes filled with liquid ion exchanger were used to study the layer of microclimate pH in the vicinity of the surface of rat jejunum in vitro.2. During perfusion with a Na+-containing solution of pH 7 30, a layer having a pH gradient ranging from 7 30 (pH of the luminal bulk phase) to 6-05 + 0-03 (pH of the deepest region) was detected in eighteen different animals. The thickness of the layer was estimated to be 600-700 ,um. No regional difference was seen along the height of the villus.3. The addition of D-glucose to the perfusion solution significantly augmented the acidity of the deepest region without changing the thickness of the layer. On the other hand, the elimination of Na+ from the perfusion solution caused a significant reduction of the pH gradient. The lowest pH changed from a control value of 6-18 + 0-15 (n = 13 measurements from three animals) to 6-46 + 0-06 (n = 13). The gradient was sensitive to amiloride in the presence of Na+. K+, Ca2' and Cl-had no significant effect on the microclimate pH.4. Depletion of the surface mucus by treatment with dithiothreitol significantly raised the pH of the deepest region.5. Glycylglycine and L-carnosine were found to reduce the microclimate pH gradient significantly, while glycine did not.6. These results indicate that H+ secretion by the Na+-H+ antiport and the formation of mucus layer are important factors for maintaining the microclimate pH layer, and that H+-coupled co-transport, such as H+-dipeptide co-transport, causes a significant diminution of the microclimate pH gradient.

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Section: Discussionmentioning

confidence: 99%

Factors affecting the microclimate pH in rat jejunum.

Shimada

1987

The Journal of Physiology

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“…In addition to mediating Na + -H + exchange (Murer et al, 1976;Aronson, 1980, 1981a;Deitmer and Ellis, 1980;Rindler and Saier, 1981;Moolenaar et al, 1981b;Aronson et al, 1982;Burnham et al, 1982;Paris and Pouyssegur, 1983;Gunther and Wright, 1983;Abercrombie and Roos, 1983). There is also evidence in microvillus membrane vesicles (Kinsella and Aronson, 1981a;Gunther and Wright, 1983 (Aronson, 1985).…”

Section: Alternative Substrates and Modesmentioning

confidence: 99%

“…Third, when the transmembrane Na + gradient is thermodynamically balanced by an H gradient of the same magnitude (i.e., when Na^/Na^ = Ho7Hi + ), the Na + -H + exchanger is at equilibrium and mediates no net flux of Na + and H + (Moody, 1981;Kinsella and Aronson, 1982), which also implies that the exchange is electroneutral and that the coupling ratio is 1.0. A Na + :H + coupling ratio of 1.0 is consistent with stoichiometries of 1:1, 2:2, 3:3, etc., but the interaction of external Na + and external H + with the Na + -H + exchanger conforms to simple saturating MichaelisMenten kinetics, with a Hill coefficient of 1.0 (Burnham et al, 1982;Ives et al, 1983a;Gunther and Wright, 1983;Frelin et al, 1983;Paris and Pouyssegur, 1983;Grinstein et al, 1984). This is most consistent with the presence of only a single binding site for external Na + or H + , and indicates that the stoichiometry of exchange is actually one Na + for one H + .…”

Section: Stoichiometrymentioning

confidence: 99%

The plasma membrane sodium-hydrogen exchanger and its role in physiological and pathophysiological processes.

Mahnensmith¹,

Aronson²

1985

Circulation Research

492

233

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SUMMARY. The plasma membranes of most if not all vertebrate cells contain a transport system that mediates the transmembrane exchange of sodium for hydrogen. The kinetic properties of this transport system include a 1:1 stoichiometry, affinity for lithium and ammonium ion in addition to sodium and hydrogen, the ability to function in multiple 1:1 exchange modes involving these four cations, sensitivity to inhibition by amiloride and its analogues, and allosteric regulation by intracellular protons. The plasma membrane sodium-hydrogen exchanger plays a physiological role in the regulation of intracellular pH, the control of cell growth and proliferation, stimulusresponse coupling in white cells and platelets, the metabolic response to hormones such as insulin and glucocorticoids, the regulation of cell volume, and the transepithelial absorption and secretion of sodium, hydrogen, bicarbonate and chloride ions, and organic anions. Preliminary evidence raises the possibility that the sodium-hydrogen exchanger may play a pathophysiological role in such diverse conditions as renal acid-base disorders, essential hypertension, cancer, and tissue or organ hypertrophy. Thus, future research on cellular acid-base homeostasis in general, and on plasma membrane sodium-hydrogen exchange in particular, will enhance our understanding of a great variety of physiological and pathophysiological processes. (Circ Res 57: 773-788, 1985)

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“…Sodium is a major electrolyte found in CHO-E beverages and ORS/sports drinks. When a CHO-E beverage is ingested, sodium is transported through the intestinal wall by diffusion (Gunther & Wright, 1983), Na + -H + exchange (Turnberg, Bieberdorf, Morawski, & Fordtran, 1970), glucose-sodium cotransport (Hopfer & Groseclose, 1979;Riklis & Quastel, 1958), and solvent drag (Fordtran, 1975;Fordtran, Rector, & Carter, 1968;Madara & Pappenheimer, 1987). Sodium absorption is influenced by different regions of the small intestine (Davis, Santa Ana, Morawski, & Fordtran, 1982) and by different types of CHO in the ingested beverage.…”

Section: Solute Absorptionmentioning

confidence: 99%

Water and Solute Absorption From Carbohydrate-Electrolyte Solutions in the Human Proximal Small Intestine: A Review and Statistical Analysis

Shi

Passe²

2010

International Journal of Sport Nutrition and Exercise Metabolism

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The purpose of this study is to summarize water, carbohydrate (CHO), and electrolyte absorption from carbohydrate-electrolyte (CHO-E) solutions based on all of the triple-lumen-perfusion studies in humans since the early 1960s. The current statistical analysis included 30 reports from which were obtained information on water absorption, CHO absorption, total solute absorption, CHO concentration, CHO type, osmolality, sodium concentration, and sodium absorption in the different gut segments during exercise and at rest. Mean differences were assessed using independent-samples t tests. Exploratory multiple-regression analyses were conducted to create prediction models for intestinal water absorption. The factors influencing water and solute absorption are carefully evaluated and extensively discussed. The authors suggest that in the human proximal small intestine, water absorption is related to both total solute and CHO absorption; osmolality exerts various impacts on water absorption in the different segments; the multiple types of CHO in the ingested CHO-E solutions play a critical role in stimulating CHO, sodium, total solute, and water absorption; CHO concentration is negatively related to water absorption; and exercise may result in greater water absorption than rest. A potential regression model for predicting water absorption is also proposed for future research and practical application. In conclusion, water absorption in the human small intestine is influenced by osmolality, solute absorption, and the anatomical structures of gut segments. Multiple types of CHO in a CHO-E solution facilitate water absorption by stimulating CHO and solute absorption and lowering osmolality in the intestinal lumen.Keywords: exercise, intestinal perfusion, sports drink, osmolality Water, carbohydrate (CHO), and electrolyte (E) absorption have been investigated in humans at rest and during exercise using a triple-lumen tube intubationperfusion technique beginning in the early 1960s (Fordtran, Levitan, Bikerman, & Burrows, 1961;Fordtran & Saltin, 1967). The triple-lumen tube intubation-perfusion technique provides a precise measurement of transport rate of water and solute in vivo at a specific intestinal site. The measurement condition is kept under a physiologic functional state. Although this technique has been recognized as a gold standard for measuring intestinal water and solute absorption and is extensively used by many investigators to study intestinal transport mechanisms, gut permeability, and the efficacy of oral rehydration solutions (ORS) and sports drinks, there are still some limitations under certain conditions, such as bypassing gastric emptying, not measuring transport of the solution being perfused, and absorption of "nonabsorbed" marker (PEG 3600 or 4000; Schedl, Maughan, & Gisolfi, 1994).Although water and solute absorption under conditions of segmental perfusion of an isotonic solution are Metabolism, 2010, 20, 427-442 © 2010 Shi is with Gatorade Sports Science Institute, PepsiCo Inc., Barrington, IL. Pas...

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Na+, Li+ and Cl− transport by brush border membranes from rabbit jejunum

Cited by 75 publications

References 21 publications

Factors affecting the microclimate pH in rat jejunum.

Factors affecting the microclimate pH in rat jejunum.

The plasma membrane sodium-hydrogen exchanger and its role in physiological and pathophysiological processes.

Water and Solute Absorption From Carbohydrate-Electrolyte Solutions in the Human Proximal Small Intestine: A Review and Statistical Analysis

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