Glucocorticoids modulate baroreflex control of renal sympathetic nerve activity

Deborah A. Scheuer, Steven W. Mifflin

Research output: Contribution to journalArticle

33 Scopus citations

Abstract

Experiments were performed to determine the effects of glucocorticoids on arterial baroreceptor reflex control of renal sympathetic nerve activity (RSNA). Intravenous infusions of phenylephrine and nitroprusside were used to produce graded changes in arterial pressure (AP) in Inactin-anesthetized male Sprague-Dawley rats. Baroreflex control of RSNA was determined during a baseline period and 2 and 3 h after administration of the glucocorticoid type II receptor antagonist Mifepristone (30 mg/kg sc) or vehicle (oil). Corticosterone (cort) treatment (100 mg cort pellet sc for 2-3 wk) increased baseline AP from 115 ± 2 to 128 ± 1 mmHg. Cort treatment also decreased the gain coefficient and increased the midpoint of the baroreflex curve. Treatment of cort rats with Mifepristone decreased AP within 2 h and increased the gain coefficient and decreased the midpoint of the baroreflex function curve back toward values measured in control rats. Mifepristone altered the baroreflex function curve even when AP was maintained at baseline levels. Therefore, these data demonstrate for the first time that glucocorticoids can modulate barorefiex control of RSNA by a mechanism that is, in part, independent of changes in AP.

Original languageEnglish
Pages (from-to)R1440-R1449
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume280
Issue number5 49-5
DOIs
StatePublished - May 2001

Keywords

  • Blood pressure regulation
  • Corticosterone
  • Hypertension
  • Sympathetic nervous system

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