Background: We have demonstrated previously that a high-salt diet (HS) produces myocardial fibrosis, left ventricular (LV) dysfunction, and renal insufficiency in adult spontaneously hypertensive rats (SHR), and that blockade of the renin-angiotensin system prevented those adverse effects of HS.; Methods and Results: Eight-week-old male SHR were divided into four groups: controls received regular rat chow (0.6 NaCl); the other three were given HS. The second group was given placebo; the third, nebivolol (2 x 10 mg/kg/day) orally; and, the fourth, the same dose of nebivolol by osmotic minipump. Rats received respective treatments for 8 weeks. The data demonstrated that the HS induced increased cardiac mass (2.85 +/- 0.05 vs. 5.36 +/- 0.22 mg/g; P < .05 in control and HS groups, respectively); LV fibrosis as indicated by higher hydroxyproline concentration; further increase in arterial pressure (161 +/- 7 vs. 184 +/- 8 mm Hg; P < .05); myocardial ischemia; and LV diastolic dysfunction. Nebivolol ameliorated the adverse cardiac effects of HS, demonstrated by decreased LV mass and fibrosis and improved coronary hemodynamics and LV function.; Conclusions: The effects of nebivolol were independent of arterial pressure. The results of this study provide important laboratory data that support a rationale for nebivolol in the treatment of patients with hypertension having diastolic dysfunction with preserved ejection fraction. J Am Soc Hypertens 2012;6(5):316-323. (C) 2012 American Society of Hypertension. All rights reserved.
