Comparative effects of olmesartan and azelnidipine on atrial structural remodeling in spontaneously hypertensive rats

Pharmacology. 2009;83(6):360-6. doi: 10.1159/000218103. Epub 2009 May 13.


The differential effects between olmesartan (OM), an angiotensin 2 type 1 receptor blocker (ARB), and azelnidipine (AZ), a calcium channel blocker (CCB), on atrial structural remodeling were studied in spontaneously hypertensive rats (SHR). Eight weeks after treatment, both OM and AZ decreased systolic blood pressure to similar levels. Histological analysis revealed that both OM and AZ had decreased the size of the atrial myocytes and interstitial fibrosis in the atrium, and that the effects of OM were greater than those of AZ. These beneficial effects of OM were associated with less atrial oxidative stress, as assessed by 3-nitrotyrosine staining, and less activation of Rac1, a regulatory component in NADPH oxidase. These results suggest that the ARB was more effective than the CCB in ameliorating atrial structural remodeling due to the suppression of oxidative stress.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II Type 1 Receptor Blockers / pharmacology*
  • Animals
  • Azetidinecarboxylic Acid / analogs & derivatives*
  • Azetidinecarboxylic Acid / pharmacology
  • Blood Pressure / drug effects
  • Calcium Channel Blockers / pharmacology*
  • Dihydropyridines / pharmacology*
  • Heart / anatomy & histology
  • Heart / drug effects
  • Heart Atria / anatomy & histology*
  • Heart Atria / drug effects*
  • Heart Atria / metabolism
  • Imidazoles / pharmacology*
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / drug effects
  • Oxidative Stress / drug effects
  • Rats
  • Rats, Inbred SHR
  • Tetrazoles / pharmacology*
  • rac1 GTP-Binding Protein / metabolism


  • Angiotensin II Type 1 Receptor Blockers
  • Calcium Channel Blockers
  • Dihydropyridines
  • Imidazoles
  • Tetrazoles
  • Azetidinecarboxylic Acid
  • olmesartan
  • rac1 GTP-Binding Protein
  • azelnidipine