scholarly journals Sodium Imbalance in Mice Results Primarily in Compensatory Gene Regulatory Responses in Kidney and Colon, but Not in Taste Tissue

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 995 ◽  
Author(s):  
Kristina Lossow ◽  
Wolfgang Meyerhof ◽  
Maik Behrens

Renal excretion and sodium appetite provide the basis for sodium homeostasis. In both the kidney and tongue, the epithelial sodium channel (ENaC) is involved in sodium uptake and sensing. The diuretic drug amiloride is known to block ENaC, producing a mild natriuresis. However, amiloride is further reported to induce salt appetite in rodents after prolonged exposure as well as bitter taste impressions in humans. To examine how dietary sodium content and amiloride impact on sodium appetite, mice were subjected to dietary salt and amiloride intervention and subsequently analyzed for ENaC expression and taste reactivity. We observed substantial changes of ENaC expression in the colon and kidney confirming the role of these tissues for sodium homeostasis, whereas effects on lingual ENaC expression and taste preferences were negligible. In comparison, prolonged exposure to amiloride-containing drinking water affected β- and αENaC expression in fungiform and posterior taste papillae, respectively, next to changes in salt taste. However, amiloride did not only change salt taste sensation but also perception of sucrose, glutamate, and citric acid, which might be explained by the fact that amiloride itself activates bitter taste receptors in mice. Accordingly, exposure to amiloride generally affects taste impression and should be evaluated with care.

Physiology ◽  
1986 ◽  
Vol 1 (2) ◽  
pp. 51-54 ◽  
Author(s):  
MJ Fregly ◽  
NE Rowland

A strong appetite for salt seems to be a normal link in the complex mechanisms that serve to maintain a normal sodium content of the organism. Experiments with rats have helped to unravel many aspects of the endocrine mechanisms that are involved in regulating sodium balance and salt appetite, but more work is needed to understand the mechanisms that induce salt appetite in different species.


1987 ◽  
Vol 252 (6) ◽  
pp. F1048-F1054
Author(s):  
W. R. Adam ◽  
A. G. Ellis ◽  
B. A. Adams

To study the role of aldosterone in the short-term control of potassium excretion, rats were gavaged with a liquid diet containing 10-20% of their daily caloric and potassium intake, with a range of sodium intakes. Levels of (effective) aldosterone at the time of gavage were manipulated by administration of spironolactone, aldosterone, and adrenalectomy. Urinary sodium, potassium, and creatinine excretion were measured in conscious unrestrained rats for 2 h after the food load, and then blood was collected for measurement of plasma potassium, aldosterone, and renin activity. Potassium excretion was dependent on both dietary potassium and a minimum dietary sodium content. Potassium excretion was reduced by spironolactone and adrenalectomy and increased by acute aldosterone treatment in most dietary groups. These results strongly suggest that the ambient levels of aldosterone are important in determining potassium excretion following food ingestion. Plasma aldosterone was higher with the higher potassium and lower sodium content diets. Changes in plasma aldosterone, with variations in dietary potassium or sodium, suggest a role for aldosterone in subsequent potassium excretion.


1989 ◽  
Vol 256 (5) ◽  
pp. F823-F829 ◽  
Author(s):  
P. J. Herman ◽  
L. L. Sawin ◽  
G. F. DiBona

To define the role of the renal nerves in the renal sodium retention of the nephrotic syndrome, experiments were conducted in rats given adriamycin to produce nephrotic syndrome. All rats developed proteinuria and hypoalbuminemia and exhibited edema formation. Adriamycin-injected nephrotic rats were subjected to bilateral renal denervation (ADRIADNX) or sham renal denervation (ADRIASHAM). Rats injected with adriamycin vehicle were subjected to bilateral renal denervation (DNX) or sham renal denervation (SHAM). Metabolic balance studies were carried out in all rats beginning on the 8th day after bilateral or sham renal denervation. Dietary sodium content was 210 meq/kg Na on days 8-12 and days 24-26 and was 10 meq/kg Na on days 13-23. Nephrotic rats demonstrated significantly greater overall (19 days) cumulative sodium balance than vehicle control rats, ADRIASHAM 8.47 +/- 0.81 vs. SHAM 5.74 +/- 0.34 meq Na, P less than 0.01. Bilateral renal denervation did not significantly affect overall cumulative sodium balance in the vehicle control rats, DNX 6.15 +/- 0.71 vs. SHAM 5.74 +/- 0.34 meq Na. However, bilateral renal denervation significantly decreased overall cumulative sodium balance in the nephrotic rats, ADRIADNX 6.59 +/- 0.56 vs. ADRIASHAM 8.47 +/- 0.81 meq Na, P less than 0.01. Results indicated that the increased renal sodium retention characteristic of nephrotic syndrome is dependent, in large part, on increased efferent renal sympathetic nerve activity.


1999 ◽  
Vol 68 (4) ◽  
pp. 741-747 ◽  
Author(s):  
C. J. C. Phillips ◽  
M. Y. I. Youssef ◽  
P. C. Chiy ◽  
D. R. Arney

AbstractThe influence of prior exposure to high salt diets on the salt appetite and the exhibition of stereotyped behaviour patterns was investigated with individually penned calves and tethered dairy cows. In the first experiment one half of a group of 12 calves received concentrates with the sodium content increased from 4 to 9 g/kg by the addition of NaCl up to weaning at 6 weeks, the other half had no supplementary NaCl added to the concentrates. Adding the NaCl increased the food intake of the calves, the time spent ruminating and live weight. Stereotyped behaviour patterns, such as self-grooming, licking the pen or buckets and ear sucking were reduced by adding NaCl. Calves were tested for their salt preference at 6 months of age by adding varying quantities of NaCl to silage. Exposing calves to supplementary NaCl in the concentrate pre-weaning increased the preferred sodium concentration of silage from 3 to 9 g/kg dry matter (DM). In the second experiment 36 tethered dairy cows received either a restricted concentrate and forage diet with a mean dietary sodium concentration of 2 g/kg DM, or the same diet but with the sodium content increased to either 7 or 12 g/kg DM by adding NaCl to the concentrates. There was no effect of NaCl on feeding or ruminating behaviour but the total amount of stereotyped behaviour, including mouthing or rubbing the tethering chain or bars, self-grooming and nosing or pawing the ground, decreased with increasing salt in the diet. It is concluded that increasing the sodium content of the diet of young calves from 4 to 9 g/kg increased their subsequent salt appetite and that increasing the salt content of the diet of calves or cows in restricted housing conditions can reduce the amount of stereotyped oral behaviour.


1990 ◽  
Vol 259 (4) ◽  
pp. R729-R735 ◽  
Author(s):  
D. A. Denton ◽  
J. R. Blair-West ◽  
M. McBurnie ◽  
P. G. Osborne ◽  
E. Tarjan ◽  
...  

The influence of systemic or intracerebroventricular (icv) administration of angiotensin II on the intakes of NaCl solution, water, and food was investigated in BALB/c mice. Systemic administration of angiotensin II had little, if any, influence on these ingestive behaviors. On the other hand, icv infusion of angiotensin II at 70 ng/day increased (P less than 0.05) intakes of NaCl solution and water by the third day of infusion. The amount of NaCl ingested daily during the infusion was two to three times body sodium content. The mean daily water intake increased to 40-60% of body weight. The vast increase in NaCl intake was not secondary to a natriuresis caused by the icv infusion of angiotensin II. The results suggest that angiotensin II has a direct effect on neural systems involved in sodium appetite in this species.


2007 ◽  
Vol 292 (1) ◽  
pp. H694-H700 ◽  
Author(s):  
David B. Nahey ◽  
John P. Collister

It has been shown that the area postrema (AP) plays a role in the development of certain types of chronic angiotensin II (ANG II)-induced hypertension in the rat but is not of great importance in the salt sensitivity of arterial pressure. It has recently been proposed, however, that elevated sodium levels may exacerbate the hypertensive effects of ANG II, which by itself dramatically affects salt sensitivity, by acting at sodium-sensing neurons in certain circumventricular organs of the brain. Thus the interactions of ANG II, sodium, and the central nervous system remain to be fully understood. The purpose of this study was to examine the role of the AP in ANG II-induced hypertension during periods of normal and elevated dietary salt. We hypothesized that an intact AP was necessary for the full development of hypertension under chronic ANG II infusion and that its role would be pronounced during periods of increased dietary sodium. To test this, male Sprague-Dawley rats underwent ablation of the area postrema (APx, n = 6) or sham operation (sham, n = 6). After 3 wk of recovery, rats were instrumented with radiotelemetry transducers for constant blood pressure and heart rate monitoring and venous catheters for vehicle infusion. After a 3-day control period of 0.9% saline infusion (7 ml/day) and 0.4% dietary sodium, a 10-day period of ANG II infusion (10 ng·kg−1·min−1) was begun, immediately followed by a second 10-day period during which rats were fed a 4.0% sodium diet. By day 6 of ANG II infusion, mean arterial pressure (MAP) in APx rats had increased to 139 ± 4 mmHg, whereas MAP in sham rats had increased to 126 ± 3 mmHg. This difference was found to be significant and continued through day 1 of the high-salt period, after which MAP of the two groups had risen to similar levels. On day 9 of high salt, MAP was again observed to be significantly higher (162 ± 1 mmHg) in APx rats when compared with sham rats (147 ± 4 mmHg.) These results do not support the hypothesis that the AP is necessary for the full development of ANG II-induced hypertension at normal or elevated levels of dietary sodium.


2001 ◽  
Vol 281 (3) ◽  
pp. E479-E488 ◽  
Author(s):  
Ken Okamoto ◽  
Weiyang Wang ◽  
Jan Rounds ◽  
Elizabeth A. Chambers ◽  
Danny O. Jacobs

Myocellular sodium homeostasis is commonly disrupted during critical illness for unknown reasons. Recent data suggest that changes in intracellular sodium content and the amount of ATP provided by glycolysis are closely related. The role of glycolysis and oxidative phosphorylation in providing fuel to the Na+-K+ pump was investigated in resting rat extensor digitorum longus muscles incubated at 30°C for 1 h. Oxidative inhibition with carbonyl cyanide m-chlorophenylhydrazone, known as CCCP (0.2 μM), or by hypooxygenation did not alter myocellular sodium or potassium content ([Na+]i, [K+]i, respectively), whereas treatment with iodoacetic acid (0.3 mM), which effectively blocked glycolysis, dramatically increased [Na+]i and the [Na+]i/[K+]i ratio. Experiments using ouabain and measurements of myocellular high-energy phosphates indicate that Na+-K+-ATPase activity is only impaired when glycolysis is inhibited. The data suggest that normal glycolysis is required to regulate intracellular sodium in fast-twitch skeletal muscles, because it is the predominant source of the fuel for the Na+-K+-ATPase.


Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 727
Author(s):  
Natalia Słabiak-Błaż ◽  
Grzegorz Piecha

The role of endogenous mammalian cardiotonic steroids (CTS) in the physiology and pathophysiology of the cardiovascular system and the kidneys has interested researchers for more than 20 years. Cardiotonic steroids extracted from toads or plants, such as digitalis, have been used to treat heart disease since ancient times. CTS, also called endogenous digitalis-like factors, take part in the regulation of blood pressure and sodium homeostasis through their effects on the transport enzyme called sodium–potassium adenosine triphosphatase (Na/K-ATPase) in renal and cardiovascular tissue. In recent years, there has been increasing evidence showing deleterious effects of CTS on the structure and function of the heart, vasculature and kidneys. Understanding the role of CTS may be useful in the development of potential new therapeutic strategies.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1484.1-1484
Author(s):  
S. Ahmed ◽  
E. Nikiphorou ◽  
J. Bayliss

Background:The role of dietary salt consumption in the etiopathogenesis of Rheumatoid Arthritis (RA), and autoimmune disease in general, has received renewed interest. This has been fueled by the increased prevalence of autoimmune disease worldwide correlating with western diets and heightened consumption of salt rich foods and also studies at the cellular level demonstrating induction of IL 17 producing T helper cells (Th17) by dietary salt.Objectives:To conduct a narrative review of observational studies and clinical trials on the role of dietary salt as an environmental risk factor for the onset and development of RA.Methods:A comprehensive search was done of the literature from 2010 to 2021, using the search terms dietary salt and RA; the native interfaces EBSCO and Ovid were used. Databases searched included Pubmed, Embase, EMCare, Medline and CINAHL using a Population, Exposure and Outcome framework; the MESH terms RA, risk factors, nutrition and salt were used. Data was extracted by an independent reviewer.Results:Out of the 72 studies initially identified, 50 were included in this review. Studies in murine models have demonstrated that high concentrations of sodium chloride promote the differentiation of T helper lymphocytes, via the serum- and glucocorticoid- inducible kinase 1 (SGK1) mediator towards the proinflammatory Th17 driven immune response. Six studies were carried out in human subjects. Study design ranged from cross sectional observational to nested case control studies. Sodium intake amongst participants characterized as having high intake, or being placed in the higher quartiles, ranged from 4.5-5grams per day. 5 out of 6 studies demonstrated that increased dietary salt consumption is associated with earlier onset RA. One study suggested an association between high salt intake and erosive disease at diagnosis and the development of anti-citrullinated protein antibodies (ACPA), although evidence was weak and from a single study only. Another study found that increased consumption of salt was only associated with risk of RA in smokers, highlighting the need to explore confounding variables further.Conclusion:This narrative review of the literature provides some evidence that supports a role of excess dietary salt consumption as a risk factor for the onset and severity of RA.Disclosure of Interests:None declared


2016 ◽  
pp. 1525
Author(s):  
Namyi Gu ◽  
Joo-Youn Cho ◽  
Kwang-Hee Shin ◽  
In-Jin Jang ◽  
Moo-Yong Rhee

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