title: Chronic 17beta-estradiol augments relaxant role of basal nitric oxide in blood vessels from rats with heart failure.
abstract: The effects of chronic 17beta-estradiol on endothelium-dependent relaxation to acetylcholine (ACh) and contraction to NG-nitro-L-arginine methyl ester (L-NAME), and endothelium-independent relaxation to sodium nitroprusside (SNP) were examined on blood vessels from rats with chronic heart failure (CHF). Two groups of ovariectomized female (50-60 days) rats were implanted with pellets containing 17beta-estradiol (25 microg/day) or vehicle, and given ligation of the left main coronary artery 1 week later. Another group of ovariectomized rats was implanted with vehicle pellets, and sham-operated. After 7 weeks, thoracic aortic rings, pulmonary artery rings, and portal vein strips were prepared for in vitro studies. Relative to sham-operated rats treated with the vehicle, vessels from vehicle-treated, coronary-ligated rats had similar relaxation to ACh and SNP but reduced response to L-NAME that was significant (P<0.05) for the aorta and portal vein but not pulmonary artery. Treatment of ligated rats with 17beta-estradiol augmented responses to L-NAME in the aorta, pulmonary artery and portal vein to values above those in sham-operated rat. 17beta-Estradiol did not affect relaxation of any vessels to SNP and increased maximum relaxation to ACh only in the portal vein. Hence, 17beta-estradiol enhances the relaxant role of basal nitric oxide in CHF.
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada.
authors.forename: A A
authors.initials: AA
authors.lastname: Nekooeian
authors.forename: S L
authors.initials: SL
authors.lastname: Lim
authors.forename: R Y
authors.initials: RY
authors.lastname: Man
authors.forename: C C
authors.initials: CC
authors.lastname: Pang
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000758:Anesthesia; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D001808:Blood Vessels / Q000187:drug effects*; D004357:Drug Synergism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology; D011169:Portal Vein / Q000187:drug effects; D011651:Pulmonary Artery / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000601:surgery; D013997:Time Factors
chemical_list: D009599:Nitroprusside; D009569:Nitric Oxide; D004958:Estradiol; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester