title: Estrogen restores role of basal nitric oxide in control of vascular tone in rats with chronic heart failure.
abstract: This study examined the cardiovascular effects of 17beta-estradiol in ovariectomized rats with heart failure. Two groups (50-60 days old) were implanted with 60-day-release pellets containing 17beta-estradiol (25 microg/day) or vehicle at 7 days before ligation of the left coronary artery. Another group was sham operated and given vehicle pellets. After 7 wk, they were studied under pentobarbital anesthesia. Relative to sham-operated rats, ligated rats had reduced mean arterial pressure (MAP, -24 +/- 6 mmHg), cardiac output (-27 +/- 4 ml/min), left ventricular (LV) end-systolic pressure (-29 +/- 8 mmHg), depressor responses to ACh (-6 +/- 4 mmHg at 7.2 microg/kg) and sodium nitroprusside (SNP, -22 +/- 6 mmHg at 9 microg/kg), and pressor responses to NG-nitro-L-arginine methyl ester (L-NAME, -14 +/- 6 mmHg at 8 mg/kg) and increased LV end-diastolic pressure (LVEDP, 10.3 +/- 0.8 mmHg) but no change in total peripheral resistance (TPR). Treatment of ligated rats with 17beta-estradiol reduced TPR (-0.19 +/- 0.06 mmHg . min . ml-1), LVEDP (-3.6 +/- 1 mmHg), and responses to ACh (-16 +/- 4 mmHg) and augmented responses to L-NAME (14 +/- 3 mmHg) but did not alter other variables. Therefore, 17beta-estradiol reduces preload and afterload and restores the vasodilator role of basal nitric oxide in ovariectomized rats with chronic heart failure.
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
authors.forename: A A
authors.initials: AA
authors.lastname: Nekooeian
authors.forename: C C
authors.initials: CC
authors.lastname: Pang
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002303:Cardiac Output, Low / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D002908:Chronic Disease; D003331:Coronary Vessels; D003692:Delayed-Action Preparations; D004343:Drug Implants; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D008026:Ligation; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009929:Organ Size; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000187:drug effects / Q000473:pathology; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D003692:Delayed-Action Preparations; D004343:Drug Implants; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; D009599:Nitroprusside; D004958:Estradiol; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester