Effects of daily sodium intake and ANG II on cortical and medullary renal blood flow in conscious rats

Volkmar Gross, Theresa M. Kurth, Meredith M. Skelton, David L. Mattson, A. W. Cowley

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Implanted optical fibers and laser-Doppler flow measurement techniques were used for the sequential measurement of regional renal blood flow in conscious rats to determine the effects of an increase of daily NaCl intake on the renal cortical blood flow and blood flow to the outer and inner medulla. Cortical blood flow was increased significantly (32%) by the second day when NaCl intake was increased from 1 to 7 meq/day and was increased further (50%) on the second day after a further elevation of NaCl intake to 13 meq/day. Blood flow to the outer and inner medulla was not changed as NaCl intake was elevated. The increase in renal cortical flow was closely associated with significant reductions in circulating concentrations of ANG II from 31 to 16 pg/ml. Rats given a continuous infusion of nonpressor doses of ANG II (5.0 ng·kg-1·min-1) to maintain constant plasma concentrations of ANG II as sodium intake was increased exhibited no increase of cortical flow. We conclude that reductions of plasma ANG II associated with incremental increases of daily sodium intake result in a rise of renal cortical flow. The elevated blood flow to the renal cortex may enhance sodium excretion and contribute to long-term sodium homeostasis.

Original languageEnglish (US)
Pages (from-to)R1317-R1323
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume274
Issue number5 43-5
DOIs
StatePublished - May 1998

Keywords

  • Angiotensin
  • Cortical blood flow
  • Medullary blood flow
  • Sodium chloride intake

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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