Effects of dietary salt changes on renal  renin-angiotensin system in rats

Ingert, C; Grima, Michèle; Coquard, Catherine; Barthelmebs, Mariette; Imbs, Jean-Louis

doi:10.1152/ajprenal.00321.2001

Cited by 64 publications

(65 citation statements)

References 38 publications

(51 reference statements)

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“…Renin is the rate-limiting step in the production of ANG II through its conversion of angiotensinogen into angiotensin I (22) and therefore gives an indication of overall endogenous RAS activity. The current study has demonstrated that plasma renin concentration was augmented in low-sodium-fed rats and markedly reduced in high-sodium-fed rats, and these data concur with findings from other groups (9,14). Furthermore, previous studies have shown both circulating (8,15) and intrarenal (9,14) ANG II levels were also increased in lowsodium-fed rats and reduced in high-sodium-fed rats.…”

Section: R264 Dietary Sodium Intake and Ang (1-7)-induced Diuresis Ansupporting

confidence: 92%

“…This was examined by 1) determining the impact of intrarenal infusion of ANG (1-7) on renal hemodynamic and excretory function; and 2) investigating how placing animals on a low-and high-sodium diet, to activate or suppress the endogenous RAS (9,14), would alter the hemodynamic and excretory actions of ANG (1)(2)(3)(4)(5)(6)(7) Surgical protocol. Rats were fasted overnight but did have access to water.…”

mentioning

confidence: 99%

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Dietary sodium intake modulates renal excretory responses to intrarenal angiotensin (1–7) administration in anesthetized rats

O’Neill

Corbett

Johns

2013

American Journal of Physiology-Regulatory, Integrative and Comp

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O'Neill J, Corbett A, Johns EJ. Dietary sodium intake modulates renal excretory responses to intrarenal angiotensin (1-7) administration in anesthetized rats. Am J Physiol Regul Integr Comp Physiol 304: R260 -R266, 2013. First published December 19, 2012 doi:10.1152/ajpregu.00583.2011-Angiotensin II at the kidney regulates renal hemodynamic and excretory function, but the actions of an alternative metabolite, angiotensin (1-7), are less clear. This study investigated how manipulation of dietary sodium intake influenced the renal hemodynamic and excretory responses to intrarenal administration of angiotensin (1-7). Renal interstitial infusion of angiotensin (1-7) in anesthetized rats fed a normal salt intake had minimal effects on glomerular filtration rate but caused dose-related increases in urine flow and absolute and fractional sodium excretions ranging from 150 to 200%. In rats maintained for 2 wk on a low-sodium diet angiotensin (1-7) increased glomerular filtration rate by some 45%, but the diuretic and natriuretic responses were enhanced compared with those in rats on a normal sodium intake. By contrast, renal interstitial infusion of angiotensin (1-7) in rats maintained on a high-sodium intake had no effect on glomerular filtration rate, whereas the diuresis and natriuresis was markedly attenuated compared with those in rats fed either a normal or low-sodium diet. Plasma renin and angiotensin (1-7) were highest in the rats on the low-sodium diet and depressed in the rats on a high-sodium diet. These findings demonstrate that the renal hemodynamic and excretory responses to locally administered angiotensin (1-7) is dependent on the level of sodium intake and indirectly on the degree of activation of the renin-angiotensin system. The exact way in which angiotensin (1-7) exerts its effects may be dependent on the prevailing levels of angiotensin II and its receptor expression.angiotensin (1-7); dietary sodium; renal hemodynamics; sodium excretion THE RENIN ANGIOTENSIN SYSTEM (RAS) is a powerful endogenous hormonal cascade that plays a central role in the regulation of blood pressure, sodium balance, and body fluid homeostasis. Classically, this cascade culminates in the formation of the potent vasoconstrictor, antinatriuretic and antidiuretic peptide angiotensin II (ANG II) (7,20). ANG II is produced from angiotensin I (ANG I) primarily via angiotensin-converting enzyme (ACE) but also via the tissue enzyme chymase. The latter has been shown to contribute to the production of ANG II in the diabetic mouse kidney (21). More recently, another RAS peptide called angiotensin (1-7) [ANG (1-7)] has been described as the endogenous counter regulator of ANG II (16) via activation of its "mas" receptor (24). ANG (1-7) is formed directly from ANG II by the ACE isoform ACE 2 (27, 32) but can also be synthesized directly from ANG I via tissue-specific peptidases such as neprilysin in the kidney (2).The intrarenal actions of ANG (1-7) and its interaction with ANG II on renal hemodynamics and tubular fluid reabsorption h...

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Section: R264 Dietary Sodium Intake and Ang (1-7)-induced Diuresis Ansupporting

confidence: 92%

mentioning

confidence: 99%

Dietary sodium intake modulates renal excretory responses to intrarenal angiotensin (1–7) administration in anesthetized rats

O’Neill

Corbett

Johns

2013

American Journal of Physiology-Regulatory, Integrative and Comp

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“…This involves endogenous Ang II as an effector of proximal reabsorption and its modulation by dietary salt. The reciprocal effects of dietary salt on plasma and kidney Ang II in the present studies were entirely expected, since we have previously documented that plasma and whole-kidney concentrations of Ang II increase during dietary salt restriction in rats (20), and others have confirmed this (21). Therefore, we surmised that Ang II would exert a lesser tonic influence over proximal reabsorption in rats fed a high-salt diet and that this would appear as a lesser decrease in proximal reabsorption during treatment with losartan.…”

Section: Discussionsupporting

confidence: 82%

An unexpected role for angiotensin II in the link between dietary salt and proximal reabsorption

Thomson

Deng²,

Wead³

et al. 2006

Journal of Clinical Investigation

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We set out to confirm the long-held, but untested, assumption that dietary salt affects proximal reabsorption through reciprocal effects on the renin-angiotensin system in a way that facilitates salt homeostasis. Wistar rats were fed standard or high-salt diets for 7 days and then subjected to renal micropuncture for determination of single-nephron GFR (SNGFR) and proximal reabsorption. The tubuloglomerular feedback (TGF) system was used as a tool to manipulate SNGFR in order to distinguish primary changes in net proximal reabsorption (Jprox) from changes due to glomerulotubular balance. The influence of Ang II over Jprox was determined by the sensitivity of Jprox to the AT1 receptor antagonist, losartan. Plasma, whole kidneys, and fluid from midproximal tubules were assayed for Ang II content by radioimmunoassay. In rats on the standard diet, losartan reduced Jprox by 25% and reduced the maximum range of the TGF response by 50%. The highsalt diet suppressed plasma and whole-kidney Ang II levels. But the high-salt diet failed to reduce the impact of losartan on Jprox or the TGF response and actually caused tubular fluid Ang II content to increase. The persistent effect of Ang II on Jprox prevented a major rise in late proximal flow rate in response to the high-salt diet. These observations challenge the traditional model and indicate that the role of proximal tubular Ang II in salt-replete rats is to stabilize nephron function rather than to contribute to salt homeostasis.

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“…No presente estudo foi avaliado se o sistema renina angiotensina e aldosterona da prole adulta sofreu influência da dieta materna durante a vida intra-uterina, uma vez que este sistema participa de forma importante na regulação da pressão arterial, do volume extracelular e da excreção e manutenção dos eletrólitos 43 . Mudanças do conteúdo de sal na dieta interferem na atividade deste sistema, no qual a dieta hipersódica diminui e a hipossódica aumenta a atividade desde sistema 45,46 . Entretanto para correlacionar e esclarecer os resultados encontrados da prole adulta foi proposto investigar também o SRA da mãe e da prole ao nascimento.…”

Section: Expressão Protéica Da Cox-2unclassified

“…O NO produzido através da nNOs no rim é importante para a secreção de renina no córtex renal. O consumo de diferentes conteúdos de sal interferem na expressão da nNOs renal [42,45] . Na literatura é descrito que a expressão gênica e protéica da nNOS aumenta durante a restrição de sódio, acompanhando o aumento da renina, e esta é suprimida com a sobrecarga de sódio na região da macula densa do córtex renal 37,38 .…”

Section: Introductionunclassified

Sobrecarga de sal durante a gestação: efeito sobre o sistema renina angiotensiva sistêmico e renal da prole adulta de ratos Wistar

Ramos¹

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Effects of dietary salt changes on renal renin-angiotensin system in rats

Cited by 64 publications

References 38 publications

Dietary sodium intake modulates renal excretory responses to intrarenal angiotensin (1–7) administration in anesthetized rats

Dietary sodium intake modulates renal excretory responses to intrarenal angiotensin (1–7) administration in anesthetized rats

An unexpected role for angiotensin II in the link between dietary salt and proximal reabsorption

Sobrecarga de sal durante a gestação: efeito sobre o sistema renina angiotensiva sistêmico e renal da prole adulta de ratos Wistar

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