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  • Electron microprobe analysis  (15)
  • Cortical collecting duct  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Cellular osmoregulation in the renal papilla (1988)
    Springer
    Journal of molecular medicine 66 (1988), S. 843-848 
    Details
    ISSN: 1432-1440
    Keywords: Renal papillary cells ; Cell electrolytes ; Osmoadaptation ; Organic osmolytes ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cells of the renal papilla are subject to extreme variations in extracellular tonicity. To obtain more insight into the mechanisms whereby these cells adapt osmotically to these unique environmental conditions, elements were measured in individual cells of the rat renal papilla in antidiuresis and after prolonged furosemide administration. In antidiuresis cell sodium, chloride and potassium concentrations did not differ fundamentally from those observed in tubule cells exposed to isotonic surroundings such as in proximal tubule cells. The marked fall in extracellular electrolyte concentrations induced by furosemide was paralleled by a far less pronounced decline in intracellular sodium, chloride and potassium concentrations. These data indicate that papillary cells achieve osmoadaptation to widely differing extracellular tonicities mainly by varying the intracellular concentrations of osmotically active substances other than inorganic electrolytes. Since high concentrations of organic osmolytes (sorbitol, inositol, glycerophosphorylcholine and other trimethylamines) have been detected in the papilla and since the tissue contents of these compounds have been shown to vary in parallel with urine osmolality, it may be concluded that metabolically inert, organic osmolytes play a dominant role in the osmoregulation of renal papillary cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728945
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  • 2
    Electronic Resource
    Electronic Resource
    The distribution of potassium, sodium and chloride across the apical membrane of renal tubular cells: effect of acute metabolic alkalosis (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 259-267 
    Details
    ISSN: 1432-2013
    Keywords: Acute metabolic alkalosis ; Distal sodium delivery ; Intracellular electrolyte concentrations ; Individual distal tubule cells ; Transmembranal electrolyte concentration gradients ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Studies were undertaken to define the effect of acute metabolic alkalosis (hypertonic sodium bicarbonate i.v.) on the chemical gradients for potassium, sodium and chloride across the apical membrane of individual renal tubule cells. Electron microprobe analysis was used on freeze-dried cryosections of the rat renal cortex to measure electrolyte concentrations in proximal tubule cells and in the various cell types of the superficial distal tubule. Analyses were also performed in fluid samples obtained by micropuncture from proximal and early and late distal collection sites. Compared with the appropriate controls (hypertonic sodium chloride i.v.), administration of sodium bicarbonate resulted only in small and mostly insignificant increases in cell potassium concentrations and induced only minor alterations in the cell/tubule fluid potassium concentration gradient for all cell types analysed. This observation suggests that under this condition factors other than an increase in cell potassium concentration are important in modulating potassium transfer across the apical membrane of potassium secreting cells. Nevertheless, since in alkalosis phosphorus and cell dry weight were decreased, and hence cell volume increased, in all but the intercalated cells, actually the potassium content of most tubular cells was higher under this condition. In comparison with animals infused with isotonic saline at low rates (hydropenic controls), infusion of either hypertonic sodium chloride or sodium bicarbonate led to a sharp increase in distal tubule fluid sodium concentrations and in the sodium concentrations of distal convoluted tubule, connecting tubule and principal cells, indicating that under both conditions the primary event causing enhanced transepithelial sodium absorption is stimulation of the sodium entry step. The ensuing rise in cell sodium concentration shold lead secondarily to stimulation of active basolateral sodium extrusion. Intercalated cell sodium concentration was higher only in alkalosis which supports the notion that this cell type is not involved in transepithelial sodium transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00585112
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  • 3
    Electronic Resource
    Electronic Resource
    A method of preparing single renal tubules for electron microprobe analysis (1983)
    Springer
    Pflügers Archiv 399 (1983), S. 241-242 
    Details
    ISSN: 1432-2013
    Keywords: Single renal tubules ; Electron microprobe analysis ; Cellular concentrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A method is described whereby single renal tubules, incubated in varying incubation media can be captured and prepared for electron microprobe analysis for intracellular sodium, potassium, chloride, phosphorus, magnesium amongst others.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656723
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  • 4
    Electronic Resource
    Electronic Resource
    The osmotic behaviour of toad skin epithelium (Bufo viridis) (1980)
    Springer
    Pflügers Archiv 385 (1980), S. 1-10 
    Details
    ISSN: 1432-2013
    Keywords: Electron microprobe analysis ; Toad skin epithelium ; Intracellular electrolyte concentrations ; Osmotic behaviour ; Salinity adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of saline adaptation on the intracellular Na, K, Cl, P concentrations and dry weight content of the toad skin epithelium (Bufo viridis) was studied using the technique of electron microprobe analysis. The measurements were performed on isolated abdominal skins either directly after dissection or after additional incubation in Ussing-type chambers. Adaptations of the toads to increasing NaCl concentrations for 7 days resulted in increased blood plasma osmolarity and a parallel increase in the cellular electrolyte, P and dry weight concentrations of the epithelium, the K increase representing the most significant fraction of the intracellular osmolarity increase. No evidence was obtained to show that the nucleus and cytoplasm reacted differently from each other and all living epithelial cell types basically showed the same response. Incubation of the isolated skins under control conditions showed a drastic inhibition of the transepithelial Na transport after adaptation to high salinities. In spite of the large variations in the transport rate almost identical intracellular electrolyte concentrations were observed. In tap water adapted toads the average cellular concentrations were 8.8 mmole/kg wet weight for Na, 109.6 for K, 41.5 for Cl, and 135.3 for P, respectively. Incubation of the skin with Ringer's solution of different osmolarities demonstrated that the epithelial cells are in osmotic equilibrium with the inner bathing solution. The results are consistent with the view that the osmotic adaptation is mainly accomplished by the movement of water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583908
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  • 5
    Electronic Resource
    Electronic Resource
    Sodium entry routes in principal and intercalated cells of the isolated perfused cortical collecting duct (1990)
    Springer
    Pflügers Archiv 416 (1990), S. 88-93 
    Details
    ISSN: 1432-2013
    Keywords: Cortical collecting duct ; Principal cells ; Intercalated cells ; Cell electrolyte concentrations ; Ouabain ; Amiloride ; Na-H exchange ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transmembrane sodium transport pathways were studied in principal and intercalated cells of the isolated perfused rabbit cortical collecting duct. Intracellular electrolyte concentrations in individual collecting duct cells were measured by electron microprobe analysis during blockage of basolateral Na-K-ATPase by ouabain and simultaneous inhibition of sodium entry across the apical and/or basolateral cell membrane. In principal cells the ouabain-induced rise in cell sodium concentration could only partially be blocked by amiloride (10−4mol/l) in the perfusion fluid. Amiloride (10−3mol/l) added to the bathing solution produced a further, significant reduction of sodium influx. In principal cells the ouabain-induced increase in sodium concentration was completely prevented by amiloride in the perfusion solution in combination with omission of sodium from the peritubular bathing solution. In intercalated cells ouabain caused a less pronounced increase in sodium concentration than in principal cells. Neither amiloride in the perfusate, nor amiloride in both bathing and perfusion solution, significantly reduced the ouabain-induced rise in intercalated cell sodium concentration. These results indicate that in principal cells amiloride-sensitive sodium channels constitute the predominant pathway for sodium entry across the apical cell membrane. In addition, substantial amounts of sodium enter principal cells across the basolateral cell membrane, probably via Na-H exchange. Finally, the data suggest that in intercalated cells sodium channels and the Na-H exchange are sparse or even absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00370227
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  • 6
    Electronic Resource
    Electronic Resource
    Intracellular elemental concentrations in renal tubular cells. An electron microprobe analysis (1979)
    Springer
    Journal of molecular medicine 57 (1979), S. 993-999 
    Details
    ISSN: 1432-1440
    Keywords: Electron microprobe analysis ; Intracellular electrolytes ; Kidney ; Ischaemia ; Elektronenstrahl-Mikroanalyse ; Intrazelluläre Elektrolyte ; Niere ; Ischämie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to be able to examine the processes involved in transepithelial transport in tissues, which are not composed of a single cell type, methods are required, which permit analysis at a cellular level. The technique of electron microprobe analysis permits the intracellular concentrations of many elements to be determined simultaneously in various portions of the cell. The application of this method to renal cortical tissue has shown that the best estimates of the cytoplasmic concentrations are to be obtained in regions close to the nucleus, farthest from the basolateral infoldings and microvilli, which separate the intracellular environment from the extracellular space. The nuclear concentrations of Na and K do not differ from those in the surrounding cytoplasm, although those of P and C1 are somewhat higher in cytoplasm. The intracellular element concentrations in the different cell types vary somewhat, proximal tubular cells contain higher concentrations of Na and C1 and lower ones of P than distal tubular cells. Following ischaemia, a manoeuvre know to result in a disturbance of intracellular electrolytes, Na was observed to rise and K to fall only in the non-surface cells of kidneys exposed to the air, but in all cells, if the kidneys were kept air-free in an atmosphere of N2. The proximal and distal tubular cells showed a variable resistance to ischaemia, the distal tubular cells being much more resistant. Despite the severity of the electrolyte disturbance following ischaemia, the intracellular composition was completely restored one hour after re-introducing renal blood flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01479984
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of amiloride on electrolyte concentrations and rubidium uptake in principal and mitochondria-rich cells of frog skin (1990)
    Springer
    Pflügers Archiv 416 (1990), S. 335-338 
    Details
    ISSN: 1432-2013
    Keywords: Rubidium ; Amiloride ; Na/K-ATPase ; Electrolyte concentrations ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The role of mitochondria-rich cells (MR cells) in transepithelial Na transport was investigated by determining electrolyte concentrations and Rb uptake in individual cells of frog skin epithelium using electron microprobe analysis. Measurements were performed under control conditions and after blocking the transepithelial Na transport with amiloride. Under control conditions, Na and Cl concentrations of MR cells scattered much more than those of principal cells and ranged from a few up to more than 30 mmol/kg wet weight. Rb uptake from the basal side into individual MR cells also showed a large variation and was, on the average, much less pronounced than into the principal cells. In principal cells, amiloride reduced the Na concentration and Rb accumulation. In contrast, no effect was observed upon electrolyte concentration and Rb uptake of MR cells. Rb uptake was correlated to the Na concentration of MR cells both under control conditions and after amiloride. It is concluded that, in contrast to the principal cells, MR cells are not involved in amiloride-sensitive transepithelial Na transport and that their Na/K-pump activity is very low.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392070
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  • 8
    Electronic Resource
    Electronic Resource
    Transcellular sodium transport and basolateral rubidium uptake in the isolated perfused cortical collecting duct (1993)
    Springer
    Pflügers Archiv 424 (1993), S. 250-254 
    Details
    ISSN: 1432-2013
    Keywords: Cortical collecting duct ; Cell Na+ concentration ; Cell Rb+ uptake ; Na+/K+-ATPase activity ; Principal cell ; Intercalated cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relation between transcellular Na+ absorption, intracellular Na+ concentration and Na+/K+-ATPase activity (the last estimated by the rubidium uptake across the basolateral cell membrane) was examined in the different cell types of the rabbit cortical collecting duct (CCD). Experiments were performed on isolated perfused CCD in which Na+ absorption was varied by perfusing the tubule with solutions containing different Na+ concentrations (nominally Na+-free, 30 mM and 144 mM). Experiments were terminated by shock-freezing the tubules during perfusion. Precisely 30 s before shock-freezing, the K+ in the bathing solution was exchanged for Rb+. Intracellular element concentrations, including Rb+, were determined in freeze-dried cryosections of the tubules using energy-dispersive X-ray analysis. Increasing Na+ concentration in the perfusion solution caused significant rises in intracellular Na+ concentration and Rb+ uptake of principal cells. Principal cell Na+ and Rb+ concentrations were 7.8±0.9 and 7.0±0.8 mmol/kg wet weight respectively, when the perfusion solution was Na+-free, 10.1±0.7 and 11.6±0.6 mmol/kg wet weight with 30 mM Na+ in the perfusion solution, and 14.5±1.5 and 14.9 ±0.9 mmol/kg wet weight with 144 mM Na+ in the perfusion solution. In contrast, a comparable relationship between lumen Na+ concentration, intracellular Na+ concentration and basolateral Rb+ uptake was not seen in intercalated cells. These results support the notion that principal, but not intercalated, cells are involved in transepithelial Na+ absorption. In addition, the data demonstrate that apical Na+ entry and basolateral Na+/K+-AT-Pase activity are closely coupled in principal cells of the rabbit CCD. A rise in lumen Na+ concentration leads to increased Na+ entry and augmented intracellular Na+ concentration, which then secondarily stimulates active basolateral Na+/K+(Rb+) exchange.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384350
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of potassium adaptation on the distribution of potassium, sodium and chloride across the apical membrane of renal tubular cells (1987)
    Springer
    Pflügers Archiv 409 (1987), S. 477-485 
    Details
    ISSN: 1432-2013
    Keywords: K adaptation ; Cell electrolyte concentrations ; Distal tubular cell types ; Micropuncture ; Chemical driving force ; Electron microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To assess the effect of K adaptation on the electrolyte concentrations of renal tubular cells and on the concentration gradients across the luminal membrane, electron microprobe analysis was employed on freeze-dried cryosections of the renal cortex and on freeze-dried samples of tubular fluid in control and high-K rats. The measurements were performed in individual cells of the proximal and superficial distal tubule and on samples of tubular fluid obtained by free flow micropuncture from proximal and early and late distal collection sites. The ingestion of a potassium-rich diet for at least 10 days together with an acute potassium load of 0.4 mmol/kg/h led to a small increase in potassium concentration of about 7 mmol/kg wet weight (w.w.) in all cell types analysed. In distal convoluted tubule, connecting tubule and principal cells sodium concentration was markedly decreased by 4, 4, and 6 mmol/kg w.w., respectively, while no significant changes in sodium concentration were found in proximal tubule and intercalated cells. No consistent changes in cell chloride could be observed under K adaptation. Analysis of the tubular fluid samples showed that the K concentration gradient across the apical cell membrane of all distal tubular cell types investigated was diminished in the high-K rats. The concentration gradient for sodium entry, however, was clearly enhanced in the distal convoluted tubule, connecting tubule and principal cells. These data suggest that an increment in cell potassium concentration is not a major functional determinant for the increased distal K secretion observed in high-K rats and that the enhanced distal sodium absorption under this condition may be due to a stimulation of the Na exit step across the basolateral cell membrane in excess of the luminal entry step in most distal tubular cell types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583804
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  • 10
    Electronic Resource
    Electronic Resource
    Electron microprobe analysis of proximal tubule cellular Na, Cl and K element concentrations during acute mannitol-saline volume expansion in rats: evidence for inhibition of the Na pump (1985)
    Springer
    Pflügers Archiv 403 (1985), S. 205-209 
    Details
    ISSN: 1432-2013
    Keywords: Electron microprobe analysis ; Volume expansion ; Intracellular electrolytes ; Renal tubular cells ; Natriuretic mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It has previously been shown that during mannitol-saline volume expansion (VE) Na transport was inhibited 50% by harvested proximal tubular fluid without a change in paracellular shunt pathway permeability to Na. To determine whether this inhibition was due to changes in cellular entry step or an effect on the pump itself, intracellular element concentrations were measured by electron microprobe X-ray ranalysis in proximal tubular cells of control (non-expanded, NE) and VE rats. Na i , Cl i and phosphorus i were increased (mean±S.E.) from 19.3±0.8 to 23.4±0.6, 15.8±0.4 to 21.3±0.4 and 124.3±2.6 to 138.0±1.8 mmol · kg−1 wet weight (P〈0.001) respectively while K i remained unchanged: 122.9±2.2 and 124.2±1.3 mmol · kg−1 wet weight. The increases in Na i and Cl i were in excess of cell shrinkage produced by the hyperosmolal peritubular environment while the unchanged K i in the face of cell shrinkage indicates and actual loss. It is concluded that mannitol-saline VE inhibits the Na pump producing a rise in Na i and a fall in K i .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00584101
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