Direct Microprobe Evidence of Local Concentration Gradients and Recycling of Electrolytes During Fluid Absorption in the Rectal Papillae of Calliphora

1980 ◽  
Vol 88 (1) ◽  
pp. 21-48 ◽  
Author(s):  
BRIJ L. GUPTA ◽  
BETTY J. WALL ◽  
JAMES L. OSCHMAN ◽  
T. A. HALL
Keyword(s):  
Extracellular Fluid ◽  
Sodium Concentration ◽  
Dry Mass ◽  
Local Concentration ◽  
Concentration Gradients ◽  
Sodium Potassium ◽  
Local Osmosis ◽  
Intercellular Channels ◽  
Tissue Compartments ◽  
Micro Analysis

1. The concentrations of sodium, potassium and chloride and dry mass were measured by electron-probe X-ray micro-analysis in 1 μm thick frozen-hydrated sections from Calliphora rectum in 5 different states of absorptive function. 2. In all cases the average concentrations of sodium + potassium + chloride was consistently higher in the fluid in the lateral intercellular spaces than in the cytoplasm, the average ratio being 2:1 in water-fed flies and higher in water-deprived flies. 3. The highest concentration of electrolytes was found in the extracellular channel of complex lateral membrane stacks, which is consistent with the histochemical localization of major cation pumps at these sites (Berridge & Gupta, 1968). This concentration exceeded the electrolyte concentration in other tissue compartments by some 80 m-equiv/1 H2O in water-fed flies and about 700 m-equiv/1 H2O in water-deprived flies. The potassium and sodium concentration ratio of this extracellular fluid was nearly 1:1 in water-fed flies, 3:1 in water-deprived flies with KC1 in the rectal lumen, and 0·5:1 with NaCl in the rectal lumen. 4. Results suggest that the extracellular fluid is generated in membrane infoldings along the intercellular channels, and that this fluid gains water and sodium, but loses a variable amount of potassium and chloride, as it passes to the haemolymph, thus supporting the idea of local osmosis and ion recycling.

Effects of cold exposure and dehydration on renal function in black-tailed prairie dogs

1977 ◽  
Vol 42 (2) ◽  
pp. 295-299 ◽  
Author(s):  
J. D. Hamilton ◽  
E. W. Pfeiffer
Keyword(s):  
Renal Function ◽  
Room Temperature ◽  
Sodium Concentration ◽  
Urine Concentration ◽  
Cynomys Ludovicianus ◽  
Prairie Dogs ◽  
Body Temperatures ◽  
Concentration Gradients ◽  
Plasma Urea ◽  
Cold Room

Black-tailed prairie dogs (Cynomys ludovicianus) were deprived of food and water for several weeks during the fall and winter in a cold-room hibernaculum (Ta 5–8 degrees C), and for several days at room temperature during the summer. Body temperatures (Tb) were determined periodically in nine animals by radiotransmitters implanted in the abdomen. Animals deprived of food and water in the summer were killed when maximum urine concentration was achieved. Eight animals in the winter were active when killed after 7–35 days in the hibernaculum with Tb between 18 and 36 degrees C. Five animals that became torpid periodically in the winter were killed after 19–42 days in the hibernaculum when their Tb indicated torpor (Tb less than 13 degrees C). Active animals in the summer and winter possessed pronounced renal corticomedullary urea and sodium concentration gradients. Torpid animals lacked these gradients and had lower urine and plasma osmotic concentrations than active animals. Plasma urea values and terminal osmolal U/P ratios were lowest in torpid prairie dogs.

Electrolyte and inulin spaces of rat salivary glands and pancreas

1960 ◽  
Vol 199 (4) ◽  
pp. 649-652 ◽  
Author(s):  
L. H. Schneyer ◽  
C. A. Schneyer
Keyword(s):  
Parotid Gland ◽  
Salivary Glands ◽  
Extracellular Fluid ◽  
Electrolyte Composition ◽  
Tissue Preparation ◽  
Sodium Potassium ◽  
Mammalian Muscle ◽  
Rat Parotid Gland ◽  
Rat Parotid ◽  
Volumes Of Distribution

Inulin, sodium, potassium and chloride levels were determined on serum and submaxillary, parotid and pancreatic glands of inulin-administered nephrectomized rats. Methods of tissue preparation and analysis were examined in some detail. From data obtained, volumes of inulin and electrolyte distribution were calculated. Volumes of distribution in submaxillary, parotid and pancreatic glands, in that order, were, for inulin, 198 ml/kg, 257 ml/kg and 209 ml/kg; for sodium, 232 ml/kg, 318 ml/kg and 275 ml/kg; and, for chloride, 365 ml/kg, 460 ml/kg and 388 ml/kg. Comparison of these values led to the conclusion that intracellular sodium in these glands is possible and that intracellular chloride is likely. Intracellular potassium seems present in concentration similar to that in mammalian muscle. From electrolyte data and levels of amylase in parotid gland and its secretion, it is speculated that parotid secretion could be formed from a small fraction (approx. 10%) derived from unmodified intracellular fluid to which is then added solution having electrolyte composition of extracellular fluid. The closely isotonic secretion of rat parotid gland can thus be predicted without assuming appreciable reabsorption of electrolytes or water.

Effectiveness of the aldosterone-sodium and -potassium feedback control system

1976 ◽  
Vol 231 (3) ◽  
pp. 945-953 ◽  
Author(s):  
DB Young ◽  
RE McCaa ◽  
UJ Pan ◽  
AC Guyton
Keyword(s):  
Feedback Control ◽  
Potassium Concentration ◽  
Extracellular Fluid ◽  
Plasma Potassium ◽  
Sodium Concentration ◽  
Feedback Mechanism ◽  
Fluid Volume ◽  
The Body ◽  
Plasma Sodium ◽  
Aldosterone Secretion

This study was conducted to determine the quantitative importance of the aldosterone feedback mechanism in controlling each one of three major factors that have often been associated with aldosterone, namely, extracellular fluid sodium concentration, extracellular fluid potassium concentration, and extracellular fluid volume. To do this, the ability of the body to control these three factors in the face of marked changes in daily sodium or potassium intake was studied under two conditions: 1) in the normal dog, and 2) in the dog in which the aldosterone feedback mechanism was prevented from functioning by removing the adrenal glands and then providing a continuous fixed level of supportive aldosterone and glucocorticoids during the low and high electrolyte intake periods. Under these conditions, removal of feedback control of aldosterone secretion decreased the effectiveness of plasma potassium control by nearly fivefold (39% vs. 8% change in plasma potassium concentration), fluid volume by sixfold (12% vs. 2% change in sodium space) and had no effect on control of plasma sodium concentration (2% change with and without feedback control of aldosterone secretion.)

Decreased distal acidification in acute hypercapnia in the dog

1983 ◽  
Vol 244 (1) ◽  
pp. F19-F27
Author(s):  
H. J. Adrogue ◽  
B. J. Stinebaugh ◽  
A. Gougoux ◽  
G. Lemieux ◽  
P. Vinay ◽  
...  
Keyword(s):  
Extracellular Fluid ◽  
Respiratory Acidosis ◽  
Fractional Excretion ◽  
Distal Nephron ◽  
Sodium Potassium ◽  
Fractional Excretion Of Sodium ◽  
Dependent Component ◽  
Voltage Dependent ◽  
Bicarbonate Infusion

The present studies evaluate the effect of acute hypercapnia on distal nephron H+ secretion (DNH+S) in vivo by means of the urine-blood PCO2 difference (U-B PCO2) in alkaline urine. Bicarbonaturia was induced by either a sodium bicarbonate infusion or L-lysine administration. Our results demonstrate that the U-B PCO2, as a function of the urinary bicarbonate concentration, was significantly lower during acute respiratory acidosis; this effect was not dependent on changes in glomerular filtration rate and/or fractional excretion of sodium, potassium, and chloride. Infusion of the sodium salts of sulfate, a nonreabsorbable anion, did not correct the diminished U-B PCO2. Amiloride caused the U-B PCO2 to fall in normocapnic dogs but not in hypercapnic dogs. When hypercapnia was superimposed in dogs with extracellular fluid volume contraction, there were no changes in the U-B PCO2. This study indicates that acute hypercapnia in the intact dog decreases DNH+S and is compatible with an effect of hypercapnia on the voltage-dependent component of urine acidification. The mechanism appears to be direct rather than secondary to factors that influence the rate of sodium delivery to the distal nephron.

Effect of chlorothiazide on renal juxtaglomerular cells and tissue electrolytes

1962 ◽  
Vol 202 (5) ◽  
pp. 905-908 ◽  
Author(s):  
Louis Tobian ◽  
Jeanette Janecek ◽  
John Foker ◽  
Dorothy Ferreira
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Heart Muscle ◽  
Aortic Wall ◽  
Muscle Fibers ◽  
Extracellular Fluid ◽  
Juxtaglomerular Cells ◽  
Sodium Potassium ◽  
Tissue Weight ◽  
Cardiac Muscle Fibers

Administration of chlorothiazide to rats for 9 weeks produces an increase of intracellular sodium and a decrease of intracellular potassium in skeletal muscle. However, in cardiac muscle, in the wall of mesenteric arterioles, in aortic wall, and in kidney there is no significant alteration in the amount of sodium, potassium, or chloride per unit of dry tissue weight. The water content of heart muscle, skeletal muscle, and kidney is not altered by chlorothiazide. The intracellular concentration of Na and K in heart muscle is likewise unaltered by chlorothiazide. However, chlorothiazide produces a highly significant 44% increase in the granularity of the juxtaglomerular cells. The data in general suggest that chlorothiazide decreases the volume of extracellular fluid, but does not reduce the content of intracellular Na. Extracellular K is reduced as well as the K inside skeletal muscle fibers. However, the amount of K inside cardiac muscle fibers is unchanged by chlorothiazide.

Aorta Electrolytes of Hypotensive Potassium-Deficient Rats

1958 ◽  
Vol 195 (2) ◽  
pp. 445-447 ◽  
Author(s):  
S. Charles Freed ◽  
Shirley St. George ◽  
Ray H. Rosenman
Keyword(s):  
Blood Pressure ◽  
Potassium Concentration ◽  
Pressure Rise ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Potassium Deficiency ◽  
Sodium Potassium ◽  
High Sodium ◽  
Blood Pressure Rise ◽  
Arterial Tone

The hypotension of potassium-deficiency is associated with a decrease in aorta potassium concentration, the sodium content remaining unchanged, resulting in a high sodium/potassium ratio. Loss of arterial tone may result and thus contribute to the lowering of blood pressure. Cortisone administration to such rats does not alter the low aorta potassium content but appreciably reduces the sodium concentration. The return to a more normal sodium/potassium ratio in the aorta following cortisone may restore the arterial tone and thus explain the blood pressure rise to normal levels.

Effect of parathyroidectomy on content and availability of skeletal sodium in the rat

1960 ◽  
Vol 198 (4) ◽  
pp. 749-753 ◽  
Author(s):  
George Nichols ◽  
Nancy Nichols
Keyword(s):  
Bone Mineral ◽  
Cell Metabolism ◽  
Extracellular Fluid ◽  
Bone Destruction ◽  
Sodium Concentration ◽  
Bone Cell ◽  
Plasma Sodium ◽  
Sodium Ions ◽  
Sodium Depletion ◽  
Sodium Metabolism

The effect of parathyroidectomy on the composition of plasma and bone has been examined in rats with and without sodium depletion. Parathyroidectomy caused a marked fall in calcium and a slight decrease in chloride in the plasma and a 7.9% increase in bone mineral sodium concentration. Sodium depletion by intraperitoneal dialysis of normal animals lowered bone mineral sodium 4% while plasma sodium and pH remained at almost normal levels. In contrast, sodium depletion following parathyroidectomy failed to lower bone sodium significantly but produced a significant acidosis and a slight decrease in plasma sodium. These findings suggest that the ability of bone to release sodium ions to protect extracellular fluid pH in acute sodium depletion is dependent on the presence of the parathyroid glands. Possible mechanisms by which parathyroid activity might influence bone sodium metabolism by changes in bone cell metabolism, changes in the Na:Ca ratio of extracellular fluid, or actual bone destruction are discussed.

scholarly journals Vortices, dissipation and flow transition in volatile binary drops

2014 ◽  
Vol 749 ◽  
pp. 649-665 ◽  
Author(s):  
R. Bennacer ◽  
K. Sefiane
Keyword(s):  
Viscous Dissipation ◽  
Flow Structure ◽  
Volatile Component ◽  
Internal Flow ◽  
Reynolds Numbers ◽  
Local Concentration ◽  
Water Mixture ◽  
Concentration Gradients ◽  
Image Velocimetry ◽  
Good Agreement

AbstractDespite its fundamental and practical relevance, flow structure and evolution within volatile mixture drops remains largely unexplored. We study experimentally, using particle image velocimetry (PIV), the evolution of internal flow during the evaporation of ethanol–water mixture drops for different initial concentrations. The investigation revealed the existence of three stages in the evolving flow behaviour within these binary volatile drops. We propose an analysis of the nature of the flow and focus on understanding successive flow stages as well as transition from multiple vortices to a monotonic outward flow. We show that the existence of multiple vortices during the first stage is driven by local concentration gradients along the interface. When the more volatile component (in this case ethanol) is depleted, the intensity of this Marangoni flow abruptly declines. Towards the end of the first stage, ethanol is driven from the bulk of the drop to the interface to sustain weakening concentration gradients. Once these gradients are too weak, the solutal Marangoni number becomes sub-critical and the driving force for the flow switches off. The evolution of flow structure and transition between stages is found to be well correlated with the ratio of Marangoni and Reynolds numbers. Furthermore, we argue that whilst the observed vortices are driven by surface tension shear stress originating at the liquid/vapour interface, the transition in flow and its dynamics is entirely determined by viscous dissipation. The comparison between the analytical expression for vorticity decay based on viscous dissipation and the experimental data shows a very good agreement. The analysis also shows that regardless of the initial concentration, for same sized drops, the transition in flow follows exactly the same trend. This further supports the hypothesis of a viscous dissipation transition of the flow. The last stage is satisfactorily explained based on non-uniform evaporation and continuity-driven flow.

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