High-NaCl diets increase natriuretic and diuretic responses in salt-resistant but not salt-sensitive SHR

M. S. Mozaffari, S. Jirakulsomchok, Z. H. Shao, J. M. Wyss

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

This study tested the hypothesis that NaCl-sensitive spontaneously hypertensive rats (SHR-S) display a defect in natriuretic and diuretic responses to acute volume loading that contributes to the rise in arterial pressure observed when the rats are fed a high-NaCl diet. Seven-week-old SHR-S and NaCl-resistant SHR rats (SHR-R) and normotensive (Wistar-Kyoto and Sprague-Dawley rats) were fed high- or basal NaCl diets. After 2.5 wk on the diets, preinstrumented conscious rats received an intravenous infusion (5% body wt; 0.5 ml/min) of isotonic saline, and urine was collected through a bladder catheter for 90 min. Control rats on the high-NaCl diet (compared with basal) excreted a significantly greater percentage of Na+ and volume load. In contrast, SHR-S on high-NaCl diet (compared with basal) had a very small increase in natriuretic response and no increase in diuretic response to volume expansion. The effect of renal denervation on natriuretic and diuretic responses to volume load was tested. In SHR-R on 1 and 8% NaCl diets, renal denervation had little or no effect on these responses, suggesting that renal nerves do not play a prominent role in the dietary NaCl-induced increases in the natriuretic and diuretic responses to volume load. These results demonstrate that NaCl-resistant rats rapidly adapt to diets high in NaCl content with increased natriuretic and diuretic responses to acute volume loading. The failure of SHR-S to adapt to the dietary challenge may result in volume loading and a secondary increase in arterial pressure after feeding.

Original languageEnglish (US)
Pages (from-to)F890-F897
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume260
Issue number6 29-6
DOIs
StatePublished - 1991
Externally publishedYes

Keywords

  • Cardiopulmonary baroreflex
  • Hypertension
  • Kidney
  • Renal nerves
  • Salt sensitivity

ASJC Scopus subject areas

  • Physiology

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