scholarly journals Plasma sodium, extracellular fluid volume, and blood pressure in healthy men

2021 ◽  
Vol 9 (24) ◽  
Author(s):  
Jacqueline J. J. O. N. Bosch ◽  
Niek R. Hessels ◽  
Folkert W. Visser ◽  
Jan A. Krikken ◽  
Stephan J. L. Bakker ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Plasma Sodium ◽  
Healthy Men

Sodium uptake from the gut of freshwater- and seawater-acclimated ducks and gulls

1988 ◽  
Vol 66 (6) ◽  
pp. 1365-1370 ◽  
Author(s):  
M. R. Hughes ◽  
J. R. Roberts
Keyword(s):  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Ion Concentration ◽  
Plasma Sodium ◽  
Salt Glands ◽  
Gut Epithelium ◽  
Seawater Acclimation ◽  
Na Uptake

The first possible regulator of plasma sodium ([Na]pl) and chloride ([Cl]pl) concentrations is the gut epithelium. Its in vivo role in uptake of ingested salt in birds with salt glands has not been evaluated. In the present study the anterior gut 22Na uptake rate was measured in freshwater-acclimated ducks (Anas platyrhynchos) and gulls (Larus glaucescens) and was then measured in the same birds after acclimation to 2/3 seawater. The 22Na was given orally in 7–10 mL of 171 mM NaCl. In ducks, seawater acclimation increased [Na]pl and [Cl]pl but not Na space; in gulls seawater acclimation increased Na space, but not plasma ion concentration. The rate of gut 22Na uptake was the same in ducks and gulls and was not affected by seawater acclimation in either species. As determined from the 22Na distribution between erythrocytes and plasma 3 h after i.v. 22NaCl injection, duck erythrocytes sequestered more (9.3% ± 0.4%) of the load than did gull erythrocytes (6.9% ± 0.3%) (P < 0.001). Although gulls are better hyperosmotic regulators than ducks, there was no difference between the two species in the entry of sodium into the extracellular fluid volume from the gut. Immediately after oral gut loading with dilute saline, freshwater-acclimated gull [Cl]pl, increased more (2P < 0.001) than could be accounted for by equilibration of the administered Cl within the extracellular fluid volume. After gut loading, the increase in [Cl]pl, of freshwater-acclimated ducks was less rapid and could be accounted for by extracellular distribution of the oral Cl load. In seawater-acclimated gulls, [Cl]pl decreased following gut loading, but was unchanged in seawater-acclimated ducks.

Rise in Extracellular Fluid Volume During High Sodium Depends on BMI in Healthy Men

Obesity ◽  
2009 ◽  
Vol 17 (9) ◽  
pp. 1684-1688 ◽  
Author(s):  
Folkert W. Visser ◽  
Jan A. Krikken ◽  
Jaap H.J. Muntinga ◽  
Rudi A. Dierckx ◽  
Gerjan J. Navis
Keyword(s):  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Healthy Men ◽  
High Sodium

Relation of saluretic and hypotensive effects of hydrochlorothiazide in the rat

1960 ◽  
Vol 198 (1) ◽  
pp. 148-152 ◽  
Author(s):  
Sydney M. Friedman ◽  
Miyoshi Nakashima ◽  
Constance L. Friedman
Keyword(s):  
Blood Pressure ◽  
Plasma Volume ◽  
Extracellular Space ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Urinary Volume ◽  
Hypertensive Rats ◽  
Inulin Space

Hydrochlorothiazide causes a marked loss of Na and of water in both fully alimented rats and in rats deprived of food and/or water. The increased urinary volume corresponds closely to the shrinkage of the extracellular fluid volume (inulin space) but the decrease in extracellular Na is not sufficient to account for the Na excretion, suggesting that Na is withdrawn from cells and perhaps bone stores as well. The fall in blood pressure in hypertensive rats is not due to simple shrinkage of the extracellular space and plasma volume, but can be referred to the rise in Na gradient induced by withdrawal of cell sodium.

Salt-Sensitivity of Volume and Blood Pressure in a Mouse with Globally Reduced ENaC γ Subunit Expression

2021 ◽  
Author(s):  
Evan C. Ray ◽  
Ashley Pitzer ◽  
Tracey Lam ◽  
Alexa Cross Jordahl ◽  
Ritam Patel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Extracellular Fluid ◽  
Body Water ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Lean Tissue ◽  
Tissue Mass ◽  
Lean Tissue Mass ◽  
Γ Subunit ◽  
Subunit Expression

The epithelial Na+ channel (ENaC) promotes the absorption of Na+ in the aldosterone-sensitive distal nephron, colon, and respiratory epithelia. Deletion of genes encoding ENaC's subunits results in early post-natal mortality. We present initial characterization of a mouse with dramatically suppressed expression of ENaC's γ subunit. We used this hypomorphic (γmt) allele to explore the importance of this subunit in homeostasis of electrolytes and body fluid volume. At baseline, γ subunit expression in γmt/mt mice was markedly suppressed in kidney and lung, while electrolytes resembled those of littermate controls. Aldosterone levels in γmt/mt mice exceeded those seen in littermate controls. Quantitative magnetic resonance (QMR) measurement of body composition revealed similar baseline body water, lean tissue mass, and fat tissue mass in γmt/mt mice and controls. γmt/mt mice exhibited a more rapid decline in body water and lean tissue mass in response to a low Na+ diet than controls. Replacement of drinking water with 2% saline selectively and transiently increased body water and lean tissue mass in γmt/mt mice, relative to controls. Lower blood pressures were variably observed in γmt/mt mice on a high salt diet, compared to controls. γmt/mt also exhibited reduced diurnal blood pressure variation, a "non-dipping" phenotype, on a high Na+ diet. While ENaC in renal tubules and colon work to prevent extracellular fluid volume depletion, our observations suggest that ENaC in other tissues may participate in regulating extracellular fluid volume and blood pressure.

scholarly journals Mechanisms of proximal tubule sodium transport regulation that link extracellular fluid volume and blood pressure

2010 ◽  
Vol 298 (4) ◽  
pp. R851-R861 ◽  
Author(s):  
Alicia A. McDonough
Keyword(s):  
Blood Pressure ◽  
Proximal Tubule ◽  
Flow Rate ◽  
Sodium Transport ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
The Body ◽  
Extracellular Fluid Volume ◽  
Ang Ii ◽  
Salt Diet

One-hundred years ago, Starling articulated the interdependence of renal control of circulating blood volume and effective cardiac performance. During the past 25 years, the molecular mechanisms responsible for the interdependence of blood pressure (BP), extracellular fluid volume (ECFV), the renin-angiotensin system (RAS), and sympathetic nervous system (SNS) have begun to be revealed. These variables all converge on regulation of renal proximal tubule (PT) sodium transport. The PT reabsorbs two-thirds of the filtered Na+ and volume at baseline. This fraction is decreased when BP or perfusion pressure is increased, during a high-salt diet (elevated ECFV), and during inhibition of the production of ANG II; conversely, this fraction is increased by ANG II, SNS activation, and a low-salt diet. These variables all regulate the distribution of the Na+/H+ exchanger isoform 3 (NHE3) and the Na+-phosphate cotransporter (NaPi2), along the apical microvilli of the PT. Natriuretic stimuli provoke the dynamic redistribution of these transporters along with associated regulators, molecular motors, and cytoskeleton-associated proteins to the base of the microvilli. The lipid raft-associated NHE3 remains at the base, and the nonraft-associated NaPi2 is endocytosed, culminating in decreased Na+ transport and increased PT flow rate. Antinatriuretic stimuli return the same transporters and regulators to the body of the microvilli associated with an increase in transport activity and decrease in PT flow rate. In summary, ECFV and BP homeostasis are, at least in part, maintained by continuous and acute redistribution of transporter complexes up and down the PT microvilli, which affect regulation of PT sodium reabsorption in response to fluctuations in ECFV, BP, SNS, and RAS.

Prazosin: Preliminary Clinical and Pharmacological Observations

1974 ◽  
Vol 48 (s2) ◽  
pp. 177s-179s ◽  
Author(s):  
P. Bolli ◽  
A. J. Wood ◽  
E. L. Phelan ◽  
D. R. Lee ◽  
F. O. Simpson
Keyword(s):  
Blood Pressure ◽  
Nervous Activity ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Exchangeable Sodium ◽  
Standing Posture ◽  
Molar Basis ◽  
Genetically Hypertensive Rats ◽  
Volume Tolerance

1. Prazosin had a considerable anti-hypertensive effect in both lying and standing posture in a mixed group of twenty-four patients in an open clinical trial. The drug was well tolerated and side-effects were few. 2. Tested on rat blood vessels, prazosin was ten times more potent on a molar basis than phentolamine in blocking the vasoconstrictor effects of noradrenaline. In the absence of vasoconstrictor nervous activity, no vasodilatation was observed. 3. In genetically hypertensive rats, prazosin in large doses caused a substantial fall in blood pressure, total exchangeable sodium and extracellular fluid volume. Tolerance to these effects started to develop within 20 days. In normotensive rats, blood pressure was lowered but total exchangeable sodium and extracellular fluid volume were not affected.

Determinants of High Blood Pressure in Salt-Deprived Renal Hypertensive Rats: Role of Changes in Plasma Volume, Extracellular Fluid Volume and Plasma Angiotensin II

1978 ◽  
Vol 55 (1) ◽  
pp. 81-87 ◽  
Author(s):  
A. J. Mourant
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
High Blood Pressure ◽  
Plasma Volume ◽  
Extracellular Fluid ◽  
Fluid Volume ◽  
Extracellular Fluid Volume ◽  
Right Atrial ◽  
Free Access ◽  
Plasma Angiotensin

1. Rats with indwelling aortic and right atrial cannulae were maintained on a sodium-free diet before and after renal arterial constriction combined with contralateral nephrectomy. Control animals underwent the same protocol except that non-constricting clips were used. 2. Plasma volumes in the salt-deprived animals were lower than previously determined values in animals with free access to sodium. After clipping plasma volume increased in the hypertensive animals. Extracellular fluid volume was increased equally in both normotensive and hypertensive animals on the second postoperative day only. 3. Before clipping and contralateral nephrectomy plasma angiotensin II values were higher than normal. After the operation angiotensin II concentrations fell to normal over a period of 14 days without significant differences between experimental and control groups. 4. It is concluded that high blood pressure after clipping may be in part maintained by increases in plasma volume. However, the results strongly suggest that other renal mechanisms are likely to be of major pathogenic importance.

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