title: Adaptation of bioassay to detect endothelium-derived relaxing factors from the canine atrial endocardium.
abstract: OBJECTIVE
  The aim of this study was to assess the release of endothelium-derived relaxing factors from the endocardium of canine atrial appendage.
  
  
  METHODS
  To study the release of endothelium-derived relaxing factor (EDRF) from intact atrial endocardial endothelium, tube-shaped sutures of canine atrial appendages were performed and effluents from these tubes were bioassayed (isolated perfused organ chamber system) for detection of EDRF in canine coronary artery.
  
  
  RESULTS
  Effluent from the right atrial appendage caused a relaxation of 58.4 +/- 10.1% and the left atrial appendage 74.9 +/- 8.5% from the initial prostagladin F2alpha contraction in coronary artery. No significant statistical difference was detected in effluent from the right and left atrial appendages. This relaxation was abolished by treating the heart tubes with Triton X-100 and reduced by treatment with LNMMA, a competitive inhibitor of nitric oxide and with indomethacin, an inhibitor of the cyclo-oxygenase pathway, also indicating the release of vasodilatory prostanoids from the endocardial endothelium.
  
  
  CONCLUSIONS
  This study showed for the first time, in vitro luminal release of EDRF and prostacyclin from the canine heart atrium. The ability of the endocardial endothelium to produce these factors could play an important role in preventing thrombus formation in the cardiac chambers.
authors.affiliation: Department of Cardiothoracic Surgery, National Heart Centre Singapore.
authors.forename: Yeow Leng
authors.initials: YL
authors.lastname: Chua
authors.forename: Paulo Roberto Barbosa
authors.initials: PR
authors.lastname: Evora
authors.forename: Andrea Carla
authors.initials: AC
authors.lastname: Celotto
authors.forename: Paul Joseph
authors.initials: PJ
authors.lastname: Pearson
authors.forename: Berent
authors.initials: B
authors.lastname: Discigil
authors.forename: Hartzell Vernon
authors.initials: HV
authors.lastname: Schaff
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001681:Biological Assay / Q000379:methods; D003331:Coronary Vessels / Q000187:drug effects; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004285:Dogs; D004699:Endocardium / Q000378:metabolism*; D045462:Endothelium-Dependent Relaxing Factors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006325:Heart Atria / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D016861:Cyclooxygenase Inhibitors; D045462:Endothelium-Dependent Relaxing Factors; D004791:Enzyme Inhibitors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D015121:6-Ketoprostaglandin F1 alpha; D007213:Indomethacin