G F DiBona1, L L Sawin. 1. Department of Internal Medicine, University of Iowa College of Medicine and Veterans Administration Medical Center, Iowa City, Iowa, USA. geradl-dibona@uiowa.edu
Abstract
BACKGROUND: Long-term metoprolol therapy improves cardiac performance and decreases mortality in patients with chronic congestive heart failure (CHF). This study examined the effect of long-term metoprolol therapy on renal sodium handling in an experimental rat model of CHF. METHODS AND RESULTS: Rats with left coronary ligation and myocardial infarction-induced CHF were treated with metoprolol (1.5 mg. kg-1. h-1) or vehicle for 3 weeks by osmotic minipump. They were then evaluated for their ability to excrete a short-term sodium load (5% body weight isotonic saline infusion over 30 minutes) and a long-term sodium load (change from low- to high-sodium diet over 8 days). All CHF rats had left ventricular end-diastolic pressure >10 mm Hg, and heart weight/body weight ratios averaged 0.68+/-0.02% (versus control of approximately 0.40%). Compared with vehicle CHF rats (n=19), metoprolol CHF rats (n=18) had lower basal values of mean arterial pressure (122+/-3 versus 112+/-3 mm Hg) and heart rate (373+/-14 versus 315+/-9 bpm) and decreased heart rate responses to intravenous doses of isoproterenol. During short-term isotonic saline volume loading, metoprolol CHF rats excreted 54+/-4% more of the sodium load than vehicle CHF rats. During long-term dietary sodium loading, metoprolol CHF rats retained 28+/-3% less sodium than vehicle CHF rats. CONCLUSIONS: Metoprolol treatment of rats with CHF results in an improved ability to excrete both short- and long-term sodium loads.
BACKGROUND: Long-term metoprolol therapy improves cardiac performance and decreases mortality in patients with chronic congestive heart failure (CHF). This study examined the effect of long-term metoprolol therapy on renal sodium handling in an experimental rat model of CHF. METHODS AND RESULTS:Rats with left coronary ligation and myocardial infarction-induced CHF were treated with metoprolol (1.5 mg. kg-1. h-1) or vehicle for 3 weeks by osmotic minipump. They were then evaluated for their ability to excrete a short-term sodium load (5% body weight isotonic saline infusion over 30 minutes) and a long-term sodium load (change from low- to high-sodium diet over 8 days). All CHFrats had left ventricular end-diastolic pressure >10 mm Hg, and heart weight/body weight ratios averaged 0.68+/-0.02% (versus control of approximately 0.40%). Compared with vehicle CHFrats (n=19), metoprololCHFrats (n=18) had lower basal values of mean arterial pressure (122+/-3 versus 112+/-3 mm Hg) and heart rate (373+/-14 versus 315+/-9 bpm) and decreased heart rate responses to intravenous doses of isoproterenol. During short-term isotonic saline volume loading, metoprololCHFrats excreted 54+/-4% more of the sodium load than vehicle CHFrats. During long-term dietary sodium loading, metoprololCHFrats retained 28+/-3% less sodium than vehicle CHFrats. CONCLUSIONS:Metoprolol treatment of rats with CHF results in an improved ability to excrete both short- and long-term sodium loads.
Authors: Gwenaëlle L Clarke; Aritra Bhattacherjee; Sarah E Tague; Wohaib Hasan; Peter G Smith Journal: J Neurosci Date: 2010-09-15 Impact factor: 6.167
Authors: Alain Cohen-Solal; Dipak Kotecha; Dirk J van Veldhuisen; Daphne Babalis; Michael Böhm; Andrew J Coats; Michael Roughton; Philip Poole-Wilson; Luigi Tavazzi; Marcus Flather Journal: Eur J Heart Fail Date: 2009-08-01 Impact factor: 15.534