Transport, electrolyte

Fig. 2. Schematic representation of relevant electrolyte transport through the renal tubule, depicting the osmolar gradient ia medullary iaterstitial fluid ia ywOj yW where represents active transport, —passive transport, hoth active and passive transport, and passive transport of H2O ia the presence of ADH, ia A, the cortex, and B, the medulla. An osmole equals a mole of solute divided by the number of ions formed per molecule of the solute. Thus one mole of sodium chloride is equivalent to two osmoles, ie, lAfNaCl = 2 Osm NaCl. ADH = antidiuretic hormone.

Very little work has been done in this area. Even electrolyte transport has not been well characterized for multicomponent electrolyte systems. Multicomponent electrochemical transport theory [36] has not been applied to transport in lithium-ion electrolytes, even though these electrolytes consist of a blend of solvents. It is easy to imagine that ions are preferentially solvated and ion transport causes changes in solvent composition near the electrodes. Still, even the most sophisticated mathematical models [37] model transport as a binary salt. 

Gum arabic. (GA) modifies paracellular water and electrolyte transport in the small intestine. Digestive Diseases and Sciences, Vol. 48, No.4, (April 2003), pp. 755-760, ISSN 0163-2116. 

Grisham, M.B., Gaginella, T.S., Ritter, C.V., Tamai, H., Be, R.M. and Granger, D.N. (1990b). The effects of neutrophil-derived oxidants on ileal mucosal permeability, electrolyte transport and epithelial cell viability in the rat. Inflammation 14, 531-542. 

FIGURE 13-1. Electrolyte transport in the airway epithelial cell. Ca, calcium cAMP, cyclic-3, 5 -adenosine monophosphate Cl, chloride Na, sodium K potassium. (From Milavetz G, Smith JJ. Cystic fibrosis. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 592, with permission.)... 

Jackson, M. J. Tai, C.-Y., Morphological correlates of weak electrolyte transport in the small intestine, in Dinno, M. A. (ed.), Structure and Function in Epithelia and Membrane Biophysics, Alan R. Liss, New York, 1981, pp. 83-96. 

Russell, D.A (1986) Mast cells in the regulation of intestinal electrolyte transport. American Journal of Physiology 251, G253—262. 

Harrison et al.172 reviewed the methods and techniques capable of assessing specific changes in GI function at the membrane, cell, and whole animal levels. Membrane-based studies record the uptake of solutes and electrolyte transport, assessing the effects of NCEs... 

Inorganic membranes can be categorized as shown in Table 2.1. The dense inorganic membranes consist of solid layers of metals (Pd, Ag, alloys) or (oxidic) solid electrolytes which allow diffusion of hydrogen (or oxygen). In the case of solid electrolytes transport of ions takes place. Another category of dense membranes consist of a porous support in which a liquid is... 

INTESTINE Characterization of a membrane potassium ion conductance in intestinal secretory cells using whole cell patch-clamp and calcium-sensitive dye techniques, 192, 309 isolation of intestinal epithelial cells and evaluation of transport functions, 192, 324 isolation of enterocyte membranes, 192, 341 established intestinal cell lines as model systems for electrolyte transport studies, 192, 354 sodium chloride transport pathways in intestinal membrane vesicles, 192, 389 advantages and limitations of vesicles for the characterization and the kinetic analysis of transport systems, 192, 409 isolation and reconstitution of the sodium-de-pendent glucose transporter, 192, 438 calcium transport by intestinal epithelial cell basolateral membrane, 192, 448 electrical measurements in large intestine (including cecum, colon, rectum), 192, 459... 

C. Wagner, Electrolytic Transport of Ions Through Solids, Adv. Catalysis 21 323 (1970). 

Cooke, H J, Reddix, R.A., 1994 Neural regulation of intestinal electrolyte transport In Johnson, L.R. (Ed ), Physiology of the gastrointestinal tract. Raven Press, New York, (NY), pp. 2083-2132. 

The rate at which the cations approach the membrane by electrolyte transport is t+I/F. It follows that the total flux of sodium ions to the membrane surface (/+) is the sum of these two terms... 

Fergus (2007), Effect of Cathode and Electrolyte Transport Properties on Chromium Poisoning in Solid Oxide Fuel Cells , Int.J. Hydrogen Energy, 32, 3664-3671. 

Pharmacological studies with selective agonists have shown that opioid control of intestinal electrolyte transport is predominantly mediated by delta opioid receptors [58], while the gastrointestinal propulsion is under the control of mu receptors [59,60]. The antidiarrheal effects of NEP inhibitors, such as acetorphan, the prodrug of thiorphan, have been compared to those of an opiate agonist, loperamide, in a model of castor oil-induced diarrhea in rats. When administered peripherally, they produced a delayed onset of diarrhea with no reduction in the gastrointestinal transit [61,62], as is commonly observed with loperamide [63],... 

Brown DR, Miller RJ. In Handbook of Physiology. Neurohormonal Control of Fluid and Electrolyte Transport in Intestinal Mucosa. Bethesda, MD American Physiological Society, 1991 527-589. 

Increased motility of the gastrointestinal tract and decreased absorption of fluid are major factors in diarrhea. Antidiarrheal drugs include antimotility agents, adsorbents, and drugs that modify fluid and electrolyte transport (Figure 24.8). 

C. Agents that modify fluid and electrolyte transport... 

Hropot M, Fowler N, Karlmark B, Giebisch G (1985) Tubular action of diuretics Distal effects on electrolyte transport and acidification. Kidney Int 28 477-489... 

The most useful way to utilize urine electrolyte information is to calculate the fractional excretion (FE), which is the proportion of the filtered load that is excreted from the plasma. If both tubular function and plasma electrolyte values are normal, increases in electrolyte FE values clearly reflect a decrement in GFR. With tubular malfunction, the direction of the change in FE values depends on the net direction of electrolyte transport (i.e., FE will increase for electrolytes that are primarily reabsorbed and will decrease for secreted electrolytes) (Finco 1997 Stockham and Scott 2002). 

The determination of renal function in anesthetized animals provides specific information on the effects of chemicals on glomerular filtration rate and renal blood flow. In addition, the ability of the kidney to reabsorb or secrete electrolytes may be determined by fractional clearance of Na+, K+, HCO3, Cl, and so on. Fractional clearance involves comparison of electrolyte clearance to the clearance of a substance such as inulin, which is removed from plasma by glomerular filtration. Thus, fractional clearance takes glomerular filtration rate into account, allowing comparisons of electrolyte transport between treated and control animals even if renal hemodynamics have changed. Nephron function may be assessed by free water clearance, representing the ability of the kidney to remove almost all Na+ from urine. 

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