Angiotensin II enhances β-adrenergic receptor-mediated vasorelaxation in aortas from young but not old rats

William E. Schutzer, Hong Xue, John F. Reed, Jean Baptiste Roullet, Sharon Anderson, Scott L. Mader

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

β-Adrenergic receptor (β-AR)-mediated (cAMP-dependent) vasorelaxation declines with advancing age. It has been shown that angiotensin II (ANG II), a potent vasoconstrictor, enhances cAMP-mediated vasorelaxation. Therefore, we questioned whether ANG II could reverse age-related, impaired β-AR-mediated vasorelaxation and cAMP production. Pretreatment of aortic rings from 6-wk-old or 6-mo-old male Fischer 344 rats with ANG II significantly enhanced vasorelaxation induced by isoproterenol (Iso), a β-AR agonist, and forskolin, a direct activator of adenylyl cyclase, but not dibutyryl-cAMP or isobutylmethylxanthine. The ANG II effect was blocked by losartan but not PD-123319 and was not observed in the aortas from 12- and 24-mo-old animals. Iso-stimulated cAMP production in the aorta was enhanced in the presence of ANG II in the 6-wk-old and 6-mo-old age groups only. Results suggest ANG II cannot reverse the age-related impairment in β-AR-dependent vasorelaxation. We conclude aging may affect a factor common to both ANG II-receptors and β-AR signaling pathways or aging may impair cross-talk between these two receptor pathways.

Original languageEnglish (US)
Pages (from-to)H2807-H2814
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number6 48-6
DOIs
StatePublished - 2000

Keywords

  • Fischer 344
  • Forskolin
  • Hypertension
  • Isoproterenol
  • cAMP

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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