Superoxide-dependent hypertension in male and female endothelin B receptor-deficient rats

Jennifer C Sullivan, Jennifer S. Pollock, David M. Pollock

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

Evidence for endothelin (ET) involvement in the control of fluid volume balance and arterial pressure has been derived in part from the observations that rats lacking the ETB receptor develop hypertension when placed on a high-salt (HS) diet. The present study was designed to determine the effect of superoxide on salt-induced hypertension in male and female ET B-deficient (sl/ sl) and wild-type control (wt) rats. After 14 days on a HS (8% NaCl) diet, female sl/sl rats had significantly elevated arterial pressure (183 ± 2 mm Hg, tail cuff) compared with female wt rats (134 ± 2 mm Hg). The response to a HS diet was lower in male sl/sl rats (166 ± 6 mm Hg) yet was significantly greater than that in male wt controls (135 ± 3 mm Hg). Separate groups of male and female sl/sl and wt rats were given tempol (1 mM in drinking water) during HS treatment. Arterial pressures were 149 ± 5 mm Hg in male and 143 ± 3 mm Hg in female sl/sl rats treated with tempol, values that were similar to those of controls on a normal salt diet. After 14 days, however, male and female sl/ sl rats recovered from the blood pressure-lowering effects of tempol. On Day 15, arterial pressures in female sl/sl rats on a HS diet were 160 ± 6 mm Hg and 177 ± 6 mm Hg in tempol-treated and untreated groups, respectively. In male sl/sl rats, arterial pressures were 155 ± 3 mm Hg and 165 ± 5 mm Hg in tempol-treated and untreated groups, respectively. On Day 15, no differences among groups with or without tempol were observed in plasma thiobarbituric acid-reactive substance (TBARS) concentrations or in urinary excretion of TBARS. Plasma ET-1 concentrations were significantly higher in female vs. male sl/sl rats. These results indicate that the early stages of salt-dependent hypertension produced by ETB receptor deficiency are dependent on superoxide and that the elevated pressure in the female rats may be due to elevated circulating levels of ET-1.

Original languageEnglish (US)
Pages (from-to)818-823
Number of pages6
JournalExperimental Biology and Medicine
Volume231
Issue number6
StatePublished - Jun 1 2006

Keywords

  • ET receptor
  • Endothelin
  • Gender
  • Reactive oxygen species
  • Salt-sensitive hypertension

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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