Aldosterone regulation of active sodium chloride transport in the lizard colon (Gallotia galloti)

One- to two-thirds of NaCl absorption in the late proximal convoluted tubule (no luminal organic solutes present) is inhibited by cyanide and thus is dependent on active transport. To examine whether this active transport-dependent NaCl transport is electrogenic or electroneutral, the effect of cyanide on transepithelial potential difference (PD) was measured in the rat proximal convoluted tubule microperfused in vivo. In the presence of an ultrafiltrate-like luminal perfusate containing glucose and alanine, cyanide addition caused the transepithelial PD to change from -0.44 +/- 0.04 to -0.05 +/- 0.03 mV (P less than 0.001). In the presence of a late proximal tubular fluid (high chloride, low bicarbonate, no organics), the transepithelial PD was 1.23 +/- 0.06 mV and was unchanged at 1.19 +/- 0.05 mV after cyanide addition (NS). To eliminate the possibility that an effect of cyanide on a putative acidification-dependent lumen-positive PD was concealing an effect on an electrogenic sodium transport-dependent lumen-negative PD, the above studies were repeated in the presence of acetazolamide. Cyanide did not affect the transepithelial PD (1.17 +/- 0.05 vs. 1.07 +/- 0.06 mV, NS). We conclude that, although cyanide-inhibitable NaCl transport is electrogenic in the presence of luminal organic solutes, it does not generate a transepithelial PD in their absence and therefore is electroneutral.

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EXPERIMENTAL STUDIES OF ACCELERATED CHLORIDE TRANSPORT IN CONCRETE

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2019.22.0139 ◽

2019 ◽

Vol 22 ◽

pp. 139-144

Author(s):

Vojtěch Zacharda ◽

Jiří Němeček

Keyword(s):

Reinforced Concrete ◽

Sodium Chloride ◽

Portland Cement ◽

Chloride Transport ◽

Experimental Studies ◽

Chloride Concentration ◽

Surface Concentration ◽

Extraction Process ◽

Reinforced Concrete Structures ◽

Free Sample

This contribution deals with the efficiency of electromigration of chlorides used as a repair method for reinforced concrete structures. Experimental studies of accelerated chloride transport tests were performed on samples of concrete without chlorides and with admixed sodium chloride during concreting. Two concrete types from Portland cement characterized with normal and low compressive strengths were studied. The electromigration was applied to penetrate chlorides into the chloride-free sample and for extraction of chlorides from the sample. The effectiveness of the chloride extraction process for rehabilitation of reinforced concrete in terms of lowering the chloride concentration in different concrete types and surface concentration was observed. Electrical extraction was found to be effective for lowering of initial chloride concentration by 15-20% after 24 hours. The decrease in surface concentrations was found in the range of 40-50%. The extraction process was found to be feasible and effective for both concrete types.

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Renin secretion and loop of Henle chloride reabsorption in the adrenalectomized rat

AJP Renal Physiology ◽

10.1152/ajprenal.1985.249.4.f596 ◽

1985 ◽

Vol 249 (4) ◽

pp. F596-F602

Author(s):

W. J. Welch ◽

C. E. Ott ◽

G. P. Guthrie ◽

T. A. Kotchen

Keyword(s):

Sodium Chloride ◽

Chloride Transport ◽

Plasma Renin ◽

Saline Infusion ◽

Renin Release ◽

Loop Of Henle ◽

Water Drinking ◽

Before And After ◽

Adrenalectomized Rats ◽

Stimulation Of

Renin release is increased in the adrenalectomized rat and is not inhibited by sodium chloride administration. The purpose of this study was to determine whether increased renin release is related to impaired absorptive chloride transport in the loop of Henle. Chloride transport in the loop was measured before and after acute saline infusion in three groups of rats: 1) saline-drinking adrenalectomized rats (Adx); 2) saline-drinking dexamethasone-treated adrenalectomized rats (Dex); and 3) water-drinking sham-operated controls. Unrelated to differences of arterial pressure, glomerular filtration rate, or net sodium chloride balance, chloride reabsorption in the loop of Henle of Adx [836 +/- 172 peq/min (SE)] was less (P less than 0.01) than in controls (1,646 +/- 353) and Dex (1,377 +/- 318) before saline infusion. After saline infusion, chloride delivery to the loop increased (P less than 0.05) in all three groups. However, loop chloride reabsorption increased (P less than 0.01) only in controls and Dex but not in Adx. Before saline infusion, plasma renin concentration (PRC) of Adx (350 +/- 108 U/ml) was greater (P less than 0.01) than that in controls (56 +/- 6) or Dex (108 +/- 36); sodium chloride infusion failed to inhibit PRC in Adx, whereas PRC was suppressed (P less than 0.01) by saline in Dex and controls. Thus stimulation of renin release in adrenalectomized animals was associated with decreased absorptive chloride transport in the loop of Henle. Dexamethasone normalized loop function and renin responsiveness to sodium chloride.

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Sodium Chloride Transport of Normal and Dietary Enlarged Rat Cecum in vitro

Digestion ◽

10.1159/000007575 ◽

1998 ◽

Vol 59 (6) ◽

pp. 676-682 ◽

Cited By ~ 5

Author(s):

Josefine Schreiner ◽

Matthias Weber ◽

Klaus Loeschke

Keyword(s):

Sodium Chloride ◽

Chloride Transport ◽

Rat Cecum

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Sodium and chloride transport along the inner medullary collecting duct: effect of saline expansion

AJP Renal Physiology ◽

10.1152/ajprenal.1980.238.6.f504 ◽

1980 ◽

Vol 238 (6) ◽

pp. F504-F508 ◽

Cited By ~ 6

Author(s):

H. H. Bengele ◽

C. Lechene ◽

E. A. Alexander

Keyword(s):

Sodium Chloride ◽

Sodium Transport ◽

Volume Expansion ◽

Chloride Transport ◽

Collecting Duct ◽

Urine Flow ◽

Fluid Reabsorption ◽

Inner Medullary Collecting Duct ◽

Chloride Excretion ◽

Medullary Collecting Duct

The effect of volume expansion on inner medullary collecting duct (IMCD) sodium transport remains controversial. Studies employing micropuncture of the IMCD base and tip were interpreted to demonstrate enhanced sodium and chloride reabsorption. Data obtained by microcatheterization evaluating only sodium transport revealed either no reabsorption or net addition. We have examined both sodium and chloride transport by microcatheterization. Volume expansion was comparable to the micropuncture studies: 0.9% saline equal to 10% body wt and then matched to urine flow. The fraction of filtered fluid, sodium, and chloride was analyzed as a function of IMCD length. In eight hydropenic rats 60% of the fluid, 71% of the sodium, and 48% of the chloride delivered to the IMCD was reabsorbed. In six volume-expanded rats no significant net reabsorption of fluid, sodium, or chloride was found. Accordingly, in contrast to the micropuncture results, we have demonstrated that net sodium chloride and fluid reabsorption are absent during volume expansion. We conclude that during volume expansion, fluid, sodium, and chloride excretion increase, in part, because of a reduction in net reabsorption along the IMCD. The degree of volume expansion does not account for the discrepancy between the two techniques.

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