Regulation by sodium intake of type 1 angiotensin II receptor mRNAs in the kidney of Sabra rats

Carole Nicco, Hélène Martin, Chana Yagil, Yoram Yagil, Lise Bankir, Nadine Bouby

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1 Scopus citations

Abstract

Objective: To study the relationship between the sensitivity to sodium content of the diet in terms of development of hypertension and the regulation of the expression of type 1 angiotensin II receptor subtypes by such a diet. Methods: The expression of angiotensin II receptor subtype (AT(1A) and AT(1B)) mRNAs was studied by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in the four zones of the kidneys of Sabra rats, sensitive or resistant to DOCA salt-induced hypertension (SBH/y and SBN/y, respectively). Rats were fed a high (8%) or normal (0.4%) NaCl diet. As vasopressin is known to be elevated in SBH/y rats and to be involved in DOCA-salt hypertension, we studied an additional group of SBH/y rats, fed a high sodium diet, enriched in water. Results: With the absence of DOCA, SBH/y rats did not develop hypertension. The high sodium diet induced a greater fall in the plasma renin activity in the SBH/y (-95%) than in the SBN/y (-63%). In the cortex (C) and inner stripe (IS), the high sodium diet decreased AT(1A) and AT(1B) mRNAs in SBH/y and SBN/y, with a higher magnitude for SBH/y, than for SBN/y (C, -28 versus -20%; IS, -42 versus -20%). The addition of water to the high sodium diet lessened the effect of sodium in the C and IS, although the plasma renin activity (PRA) was not altered. Conclusion: A high sodium diet significantly decreases both AT(1A) and AT(1B) gene expression in two specific zones of the rat kidney containing the target cells of angiotensin II (C and IS). This down-regulation is organ-specific since it was observed in the kidney and adrenals, but not in the liver. Finally, SBH/y and SBN/y rats differ in the basal level of AT1 mRNA expression in the IS, and in the ability to modulate AT1 mRNA level under sodium intake. (C) Lippincott Williams and Wilkins.

Original languageEnglish
Pages (from-to)1097-1105
Number of pages9
JournalJournal of Hypertension
Volume18
Issue number8
DOIs
StatePublished - 1 Jan 2000

Keywords

  • AT(1A) and AT(1B)
  • Adrenal
  • Hypertension
  • Water intake

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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