title: Influence of ovariectomy in the right ventricular contractility in heart failure rats.
abstract: BACKGROUND
  Clinical studies in postmenopausal women suggest that female hormones play an important role in maintaining healthy cardiovascular conditions. The objective of this study was to evaluate the influence of ovarian hormones in the right ventricle contractility in heart failure (HF) rats following myocardial infarction (MI).
  
  
  METHODS
  Female Wistar rats were divided into four groups: healthy ovariectomized (OVX), ovariectomized with HF (OVX-HF), HF, and sham operated (SHAM). Ovariectomy was performed in 10-week-old rats, and MI was induced 1 week later. Eight weeks after MI, right ventricular (RV) performance was analyzed using RV strip preparations.
  
  
  RESULTS
  Ovariectomy did not change the infarct size (HF: 42 +/- 3.5 vs. OVX-HF: 39 +/- 1.5%). In the presence of isoproterenol (ISO) and calcium, the isometric force was reduced in both HF groups. Ovariectomy did not modify the positive inotropic parameter in the control and in HF rats. Time to peak tension (TPT) was prolonged in both ovariectomized groups compared to SHAM (ISO 10(-7) M OVX: 125 +/- 12( *); SHAM: 81 +/- 4; HF: 87 +/- 4; OVX-HF: 102 +/- 6( *) msec, ( *)p <0.01 vs. SHAM), and relaxation time (RT) was prolonged in OVX (270 +/- 16( *) msec) and OVX-HF (241 +/- 10( *) msec) vs. SHAM (197 +/- 6 msec; ( *)p <0.01 vs. SHAM).
  
  
  CONCLUSIONS
  We conclude that the absence of female ovarian hormones during nine weeks does not influence the right ventricle positive inotropic response, but it prolongs the time of contraction and relaxation in normal and in HF rats following MI.
authors.affiliation: Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, ES, Brazil.
authors.forename: Karina
authors.initials: K
authors.lastname: Giuberti
authors.forename: Raquel Binda
authors.initials: RB
authors.lastname: Pereira
authors.forename: Patricia Rocon
authors.initials: PR
authors.lastname: Bianchi
authors.forename: Altemar Santos
authors.initials: AS
authors.lastname: Paigel
authors.forename: Dalton Valentim
authors.initials: DV
authors.lastname: Vassallo
authors.forename: Ivanita
authors.initials: I
authors.lastname: Stefanon
mesh_terms: D000818:Animals; D002303:Cardiac Output, Low / Q000209:etiology / Q000503:physiopathology*; D002316:Cardiotonic Agents / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology*; D005260:Female; D006352:Heart Ventricles / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000150:complications*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology*
chemical_list: D002316:Cardiotonic Agents; D004967:Estrogens; D007545:Isoproterenol