Cyclooxygenase-1 inhibition attenuates angiotensin II-salt hypertension and neurogenic pressor activity in the rat

Ninitha Asirvatham-Jeyaraj, Andrew J. King, Carrie A. Northcott, Shivanshu Madan, Gregory D. Fink

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Cyclooxygenase (COX)-derived prostanoids contribute to angiotensin II (ANG II) hypertension (HTN). However, the specific mechanisms by which prostanoids act are unclear. ANG II-induced HTN is caused partly by increased sympathetic nervous system activity, especially in a setting of high dietary salt intake. This study tested the hypothesis that COX-derived prostanoids cause ANG II-salt sympathoexcitation and HTN. Experiments were conducted in conscious rats. Infusion of ANG II (150 ng·kg-1·min-1sc) caused a marked HTN in rats on 2% salt diet, but a much smaller increase in blood pressure in rats on 0.4% salt diet. The nonselective COX inhibitor ketoprofen (2 mg/kg sc) given throughout the ANG-II infusion period attenuated HTN development in rats on 2% NaCl diet, but not in rats on 0.4% NaCl diet. The acute depressor response to ganglion blockade was used to assess neurogenic pressor activity in rats on 2% NaCl diet. Ketoprofentreated rats showed a smaller fall in arterial pressure in response to ganglion blockade during ANG-II infusion than did nontreated controls. In additional experiments, ketoprofen-treated rats exhibited smaller increases in plasma norepinephrine levels and whole body norepinephrine spillover than we previously reported in ANG II-salt HTN. Finally, the effects of the selective COX-1 inhibitor SC560 (10 mg·kg-1·day-1 ip) and the selective COX-2 inhibitor nimesulide (10 mg·kg-1·day-1 ip) were investigated. Treatment with SC560 but not nimesulide significantly reduced blood pressure and the depressor response to ganglion blockade in ANG II-salt HTN rats. The results suggest that COX-1 products are critical for sympathoexcitation and the full development of ANG II-salt HTN in rats.

Original languageEnglish (US)
Pages (from-to)H1462-H1470
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume305
Issue number10
DOIs
StatePublished - Nov 15 2013
Externally publishedYes

Keywords

  • Angiotensin II
  • Cyclooxygenase
  • Hypertension
  • Salt
  • Sympathetic

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