Lability of renal papillary tissue composition in the rat.

Atherton, John C.

doi:10.1113/jphysiol.1978.sp012150

“…Finally, the methods used to assess tubular function have sometimes been open to criticism. Thus, Holstein-Rathlou et al (1982) investigated proximal tubular function using different methods in conscious and anaesthetized animals; while Linas et al (1980) assessed sodium reabsorption in the distal nephron by measuring free water clearance during maximal water diuresis (Schuster & Seldin, 1985), the interpretation of which is hampered by the possibility of anaesthesia-induced changes in the medullary osmotic gradient (Atherton, 1978).…”

Section: Discussionmentioning

confidence: 99%

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

Walter

¹

,

Zewde

²

,

Shirley

³

1989

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SUMMARYRenal function was assessed in unrestrained conscious rats during either their active period (i.e. the hours of darkness) or their inactive period. On the following day, measurements were repeated after Inactin anaesthesia and preparation for clearance studies. In rats anaesthetized during their active period, preparation for clearance studies had no effect on inulin clearance (used as a measure of glomerular filtration rate), lithium clearance (used as an estimate of endproximal fluid delivery) or fractional lithium excretion. In rats anaesthetized during their inactive period, the same procedures resulted in increases in all three variables, to reach values indistinguishable from those in animals studied during their active period. In both groups of rats there were increases in the fractional reabsorption of sodium and water in the distal nephron and in the urinary excretion of potassium. It is concluded that in anaesthetized rats prepared for clearance studies, rates of glomerular filtration and proximal tubular reabsorption (as indicated by lithium clearance) are similar to those in conscious animals during their active period.

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“…To shorten the surgical procedure, ureteral urine was not collected at nephrectomy. Because papillary composition has been shown to be extremely labile (2), collection of ureteral urine at the time of nephrectomy will be necessary for future physiological studies. The finding of closed collecting-duct lumina, although not typical of micropuncture preparations, may reflect a normal condition.…”

Section: Discussionmentioning

confidence: 99%

Application of scanning electron microscopy to x-ray analysis of frozen-hydrated sections. III. Elemental content of cells in the rat renal papillary tip.

Bulger¹,

Beeuwkes²,

Saubermann³

1981

The Journal of Cell Biology

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The electrolyte and water content of cellular and interstitial compartments in the renal papilla of the rat was determined by x-ray microanalysis of frozen-hydrated tissue sections . Papillae from rats on ad libitum water were rapidly frozen in a slush of Freon 12, and sectioned in a cryomicrotome at -30 to -40°C . Frozen 0.5-,um sections were mounted on carbon-coated nylon film over a Be grid, transferred cold to the scanning microscope, and maintained at -175°C during analysis . The scanning transmission mode was used for imaging. Structural preservation was of good quality and allowed identification of tissue compartments . Tissue mass (solutes + water) was determined by continuum radiation from regions of interest . After drying in the SEM, elemental composition of morphologically defined compartments (solutes) was determined by analysis of specific x-rays, and total dry mass by continuum. Na, K, CI, and H2O contents in collecting-duct cells (CDC), papillary epithelial cells (PEC), and interstitial cells (IC) and space were measured . Cells had lower water content (mean 58 .7%) than interstitium (77.5%) . Intracellular K concentrations (millimoles per kilogram wet weight) were unremarkable (79-156 mm/kg wet weight) ; P was markedly higher in cells than in interstitium . S was the same in all compartments . Intracellular Na levels were extremely high (CDC, 344 ± 127 SD mm/kg wet weight ; PEC, 287 ± 105; IC, 898 ± 194) . Mean interstitial Na was 590 ± 119 mm/Kg wet weight . CI values paralleled those for Na . If this Na is unbound, then these data suggest that renal papillary interstitial cells adapt to their hyperosmotic environment by a Na-uptake process.Cells of the rat renal papilla are exposed to wide changes in the ionic and osmotic composition of their environment . The papillary epithelium of the rat is exposed to urine whose osmolality ranges from <100 to >3,000 mosmol/kg H2O. Tubular and interstitial cells within the papilla live in the hypertonic environment associated with the urine-concentrating mechanism. Because few mammalian cell types are exposed to such environmental conditions, the mechanism by which these cells adapt to the high salt and urea content of their environment is of great interest to cell biologists. and Morgan (20), using in vitro centrifugation or incubation techniques, have reported that the Na content of papillary cells increases with increasing osmolality and reaches more than 400 mM. However, until recently no method existed for the 274 definition of chemical composition of defined cell types within the papilla. The development of techniques for direct x-ray microanalysis of frozen-hydrated tissue sections (19,22,23) now makes such analysis possible. MATERIALS AND METHODSSix male Long-Evans rats (bred in our colony), weighing 125-200 g, were housed individually in metabolic cages for 2 dor more before the experiment . They were given Purina Rat Chow (0.29% Na, 0.46% K; Ralston Purina Co., St. Louis, Mo.) and water ad libitum. An overnight urine sample was collecte...

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Urinary Concentration and Dilution: Models

Stephenson

¹

1992

Comprehensive Physiology

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The sections in this article are: Whole‐Body Water and Solute Balance Osmolal Clearance Effect on Plasma Osmolality of Urine Flow of a Given Osmolality Hypertonic Urine Implies a Hypotonic Tubular Reabsorbate and Vice Versa Free Water Clearance Antidiuretic Hormone Controls Water Excretion Functional Implications of Renal Architecture Production of Hyperosmotic Urine Is Related to the Loop of Henle Significance of the S‐Shaped Configuration of the Mammalian Nephron for the Concentration of Urine New Functional Features Introduced by the S‐Shaped Configuration A Short History of Models of the Renal Counterflow System Active Water Transport Concentration by Differential Permeabilities and Counterflow Concentration by Multiplication of a “Single Effect” along the Loop of Henle Active Salt Transport out of the AHL Is the Probable Single Effect Experimental Predictions of the Kuhn Models Problems with the Kuhn Models Vasa Recta Models Nephrovascular Models Equations for the Renal Medulla Differential Equations Integrated Mass Balance Equations Generalized Multiplication Rule Nephrovascular Coupling Transmural Fluxes Analytical Solution of the Differential Equations Solutions for Single Flow Tubes Analytical Solutions of Multitube Counterflow Problems Solutions for Central Core Model Externally Driven Central Core Multiplier Multiplication in Inner and Outer Medullae Non‐Zero Diffusion Coefficient Solution of Time‐Dependent Equations Numerical Solution of the Differential Equations Method of Lines Shooting Method Quasilinearization Finite Difference Methods Results of Computer Simulation Origin of Inner Medullary Concentration Gradient Role of Collecting Duct Role of Vasa Recta Transition from Diuresis to Antidiuresis Free‐Energy Balance in Renal Counterflow Systems Summary and Future Directions

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Lability of renal papillary tissue composition in the rat.

Cited by 9 publications

References 13 publications

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

The Effect of Anaesthesia and Standard Clearance Procedures on Renal Function in the Rat

Application of scanning electron microscopy to x-ray analysis of frozen-hydrated sections. III. Elemental content of cells in the rat renal papillary tip.

Urinary Concentration and Dilution: Models

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