Comparison of systemic and direct intrarenal angiotensin II blockade on sodium excretion in rats

Yan Peng, Franklyn G. Knox

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

To dissociate the renal effects from the systemic effects of angiotensin II blockade, the present study was designed to determine the effects of systemic and renal interstitial infusion of the specific angiotensin II (ANG II) receptor antagonist, losartan, on blood pressure and sodium excretion in rats fed a low-, normal, or high-sodium diet. Fractional sodium excretion (FENa) and mean arterial pressure (MAP) were measured in rats before and during systemic infusion of losartan (10 mg/kg) or renal interstitial infusion of losartan (3 mg/kg) by means of a chronically implanted matrix. In rats fed a low- or normal sodium diet, systemic infusion of losartan markedly decreased MAP (Δ -21 ± 2, Δ - 10 ± 2 mmHg, respectively; P < 0.05) with an accompanying fall in FENa (Δ -0.10 ± 0.05, Δ -0.91 ± 0.40%, respectively; P < 0.05). In contrast, preferential blockade of renal ANG II with renal interstitial losartan infusion resulted in an increase in FENa (Δ0.13 ± 0.04, Δ0.95 ± 0.45%, respectively; P < 0.05) and no significant change in MAP. In rats fed a high-sodium diet, both systemic and renal interstitial infusion of losartan increased FENa (Δ1.90 ± 0.26, Δ1.40 ± 0.56%, respectively; P < 0.05). Although systemic infusion of losartan decreased MAP (Δ -4.4 ± 0.6 mmHg, P < 0.05) in rats fed a high-sodium diet, the reduction in MAP was much less than that in rats fed a low- and normal sodium diet. In conclusion, in rats fed a low- or normal sodium diets, systemic ANG II blockade reduced both arterial blood pressure and sodium excretion, whereas intrarenal ANGII blockade had no effect on blood pressure and increased sodium excretion. In contrast, both systemic and intrarenal ANG II blockade increased sodium excretion without marked effects on blood pressure in rats fed a high-sodium diet.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume269
Issue number1 38-1
StatePublished - Jul 1995

Fingerprint

angiotensin II
Angiotensin II
high sodium diet
excretion
Losartan
Sodium
sodium
rats
kidneys
Arterial Pressure
blood pressure
Diet
Kidney
Blood Pressure
diet
Sodium-Restricted Diet
antagonists
Angiotensin Receptor Antagonists
receptors

Keywords

  • Losartan
  • Renin angiotensin
  • Sodium depletion

ASJC Scopus subject areas

  • Physiology
  • Agricultural and Biological Sciences(all)

Cite this

@article{c5a5c2338fab46ac8a1bb8a876852ad9,
title = "Comparison of systemic and direct intrarenal angiotensin II blockade on sodium excretion in rats",
abstract = "To dissociate the renal effects from the systemic effects of angiotensin II blockade, the present study was designed to determine the effects of systemic and renal interstitial infusion of the specific angiotensin II (ANG II) receptor antagonist, losartan, on blood pressure and sodium excretion in rats fed a low-, normal, or high-sodium diet. Fractional sodium excretion (FENa) and mean arterial pressure (MAP) were measured in rats before and during systemic infusion of losartan (10 mg/kg) or renal interstitial infusion of losartan (3 mg/kg) by means of a chronically implanted matrix. In rats fed a low- or normal sodium diet, systemic infusion of losartan markedly decreased MAP (Δ -21 ± 2, Δ - 10 ± 2 mmHg, respectively; P < 0.05) with an accompanying fall in FENa (Δ -0.10 ± 0.05, Δ -0.91 ± 0.40{\%}, respectively; P < 0.05). In contrast, preferential blockade of renal ANG II with renal interstitial losartan infusion resulted in an increase in FENa (Δ0.13 ± 0.04, Δ0.95 ± 0.45{\%}, respectively; P < 0.05) and no significant change in MAP. In rats fed a high-sodium diet, both systemic and renal interstitial infusion of losartan increased FENa (Δ1.90 ± 0.26, Δ1.40 ± 0.56{\%}, respectively; P < 0.05). Although systemic infusion of losartan decreased MAP (Δ -4.4 ± 0.6 mmHg, P < 0.05) in rats fed a high-sodium diet, the reduction in MAP was much less than that in rats fed a low- and normal sodium diet. In conclusion, in rats fed a low- or normal sodium diets, systemic ANG II blockade reduced both arterial blood pressure and sodium excretion, whereas intrarenal ANGII blockade had no effect on blood pressure and increased sodium excretion. In contrast, both systemic and intrarenal ANG II blockade increased sodium excretion without marked effects on blood pressure in rats fed a high-sodium diet.",
keywords = "Losartan, Renin angiotensin, Sodium depletion",
author = "Yan Peng and Knox, {Franklyn G.}",
year = "1995",
month = "7",
language = "English (US)",
volume = "269",
journal = "American Journal of Physiology - Heart and Circulatory Physiology",
issn = "0363-6135",
publisher = "American Physiological Society",
number = "1 38-1",

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TY - JOUR

T1 - Comparison of systemic and direct intrarenal angiotensin II blockade on sodium excretion in rats

AU - Peng, Yan

AU - Knox, Franklyn G.

PY - 1995/7

Y1 - 1995/7

N2 - To dissociate the renal effects from the systemic effects of angiotensin II blockade, the present study was designed to determine the effects of systemic and renal interstitial infusion of the specific angiotensin II (ANG II) receptor antagonist, losartan, on blood pressure and sodium excretion in rats fed a low-, normal, or high-sodium diet. Fractional sodium excretion (FENa) and mean arterial pressure (MAP) were measured in rats before and during systemic infusion of losartan (10 mg/kg) or renal interstitial infusion of losartan (3 mg/kg) by means of a chronically implanted matrix. In rats fed a low- or normal sodium diet, systemic infusion of losartan markedly decreased MAP (Δ -21 ± 2, Δ - 10 ± 2 mmHg, respectively; P < 0.05) with an accompanying fall in FENa (Δ -0.10 ± 0.05, Δ -0.91 ± 0.40%, respectively; P < 0.05). In contrast, preferential blockade of renal ANG II with renal interstitial losartan infusion resulted in an increase in FENa (Δ0.13 ± 0.04, Δ0.95 ± 0.45%, respectively; P < 0.05) and no significant change in MAP. In rats fed a high-sodium diet, both systemic and renal interstitial infusion of losartan increased FENa (Δ1.90 ± 0.26, Δ1.40 ± 0.56%, respectively; P < 0.05). Although systemic infusion of losartan decreased MAP (Δ -4.4 ± 0.6 mmHg, P < 0.05) in rats fed a high-sodium diet, the reduction in MAP was much less than that in rats fed a low- and normal sodium diet. In conclusion, in rats fed a low- or normal sodium diets, systemic ANG II blockade reduced both arterial blood pressure and sodium excretion, whereas intrarenal ANGII blockade had no effect on blood pressure and increased sodium excretion. In contrast, both systemic and intrarenal ANG II blockade increased sodium excretion without marked effects on blood pressure in rats fed a high-sodium diet.

AB - To dissociate the renal effects from the systemic effects of angiotensin II blockade, the present study was designed to determine the effects of systemic and renal interstitial infusion of the specific angiotensin II (ANG II) receptor antagonist, losartan, on blood pressure and sodium excretion in rats fed a low-, normal, or high-sodium diet. Fractional sodium excretion (FENa) and mean arterial pressure (MAP) were measured in rats before and during systemic infusion of losartan (10 mg/kg) or renal interstitial infusion of losartan (3 mg/kg) by means of a chronically implanted matrix. In rats fed a low- or normal sodium diet, systemic infusion of losartan markedly decreased MAP (Δ -21 ± 2, Δ - 10 ± 2 mmHg, respectively; P < 0.05) with an accompanying fall in FENa (Δ -0.10 ± 0.05, Δ -0.91 ± 0.40%, respectively; P < 0.05). In contrast, preferential blockade of renal ANG II with renal interstitial losartan infusion resulted in an increase in FENa (Δ0.13 ± 0.04, Δ0.95 ± 0.45%, respectively; P < 0.05) and no significant change in MAP. In rats fed a high-sodium diet, both systemic and renal interstitial infusion of losartan increased FENa (Δ1.90 ± 0.26, Δ1.40 ± 0.56%, respectively; P < 0.05). Although systemic infusion of losartan decreased MAP (Δ -4.4 ± 0.6 mmHg, P < 0.05) in rats fed a high-sodium diet, the reduction in MAP was much less than that in rats fed a low- and normal sodium diet. In conclusion, in rats fed a low- or normal sodium diets, systemic ANG II blockade reduced both arterial blood pressure and sodium excretion, whereas intrarenal ANGII blockade had no effect on blood pressure and increased sodium excretion. In contrast, both systemic and intrarenal ANG II blockade increased sodium excretion without marked effects on blood pressure in rats fed a high-sodium diet.

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