Renal responses to hypertonic saline infusion in salt-sensitive spontaneously hypertensive rats

Mahmood S. Mozaffari, Sanya Roysommuti, Zuohai H. Shao, J. Michael Wyss

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

In Wistar Kyoto (WKY) and Sprague Dawley rats, high dietary sodium chloride (NaCl) increases natriuretic and diuretic responses to acute isotonic saline infusion, but in NaCl-sensitive spontaneously hypertensive rats (SHR-S), a high-NaCl diet causes negligible increases in natriuretic and diuretic responses. To investigate whether this deficit in sodium and fluid excretion in SHR-S is stimulus (volume)-specific or because of a more generalized alteration in renal function, the present study measured, in SHR- S and Wistar Kyoto rats, natriuretic and diuretic responses to a hypertonic saline infusion (the Amount of sodium infused was equal to that infused in a previous, isotonic experiment). Eight-week-old Wistar Kyoto rats, SHR-S, and salt-resistant SHR were given a basal (1%) or high (8%)-NaCl diet for 2 weeks. Intravenous infusion of hypertonic saline increased mean arterial pressure and reduced heart rate in all groups. Baseline sodium excretion was lower in SHR-S compared with salt-resistant SHR with either diet, but after infusion of hypertonic saline, all 6 groups displayed significant increases in sodium and fluid excretion, glomerular filtration rate, and effective renal blood flow (ERBF). The percent-sodium excretion in response to hypertonic saline infusion was slightly, but significantly, lower in SHR-S (compared with salt-resistant SHR) for either the basal or the high-NaCl diet. We conclude that renal responses to hypertonic saline infusion are affected minimally in SHR-S compared with salt-resistant SHR or Wistar Kyoto rats. Therefore, the deficits in renal function observed in SHR-S after volume loading are not reflected in a renal deficit to hypertonic saline challenge.

Original languageEnglish (US)
Pages (from-to)370-376
Number of pages7
JournalAmerican Journal of the Medical Sciences
Volume314
Issue number6
DOIs
StatePublished - Dec 1997

Keywords

  • High salt
  • Hypertensive rat
  • Hypertonic saline
  • Natriuretic

ASJC Scopus subject areas

  • Medicine(all)

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