title: [Effects of genistein on contractility of isolated right ventricular muscles in guinea pig].
abstract: OBJECTIVE
  To study the effect of genistein (GEN) on contractility of isolated right ventricular muscles in guinea pig and its mechanisms.
  
  
  METHODS
  Isolated guinea pig ventricular muscles were suspended in organ baths containing K-H solution.After an equilibration period, the effect of GEN on contraction of myocardium was observed.
  
  
  RESULTS
  GEN and isoprenaline hydrochloride had the positive inotropic effects on contractity of myocardium. Meanwhile, the effect of GEN (1-100 micromol x L(-1)) was in dose-dependent manner. Propranolol (1 micromol x L(-1)) and verapamil hydrochloride (0.5 micromol x L(-1)) attenuated the positive inotropic effect of isoprenaline hydrochloride (1 micromol x L(-1)), but did not change the effect of GEN (50 micromol x L(-1)). Further more, the enhancement of the contraction induced by elevation of extracellular Ca2+ concentration in ventricular muscles had no change after pretreatment with GEN (1.10 micromol x L(-1)). In addition,the positive inotropic effect of GEN was inhibited partially by tamoxifen (1 micromol x L(-1)) and SQ22536 (1 micromol x L(-1)), also, could be attenuated by bpV (1 micromol x L(-1)).
  
  
  CONCLUSIONS
  GEN has the positive inotropic effect on guinea pig ventricular muscles, which is not related to the activation of beta adrenoceptor, Ca2+ channel on cell membrane,but may involve in cAMP of intracellular signal transduction and tyrosine kinase pathway.
authors.affiliation: Department of Physiology, Xuzhou Medical College, Xuzhou 221004, China.
authors.forename: Jin-xia
authors.initials: JX
authors.lastname: Wu
authors.forename: Hong-fang
authors.initials: HF
authors.lastname: Li
authors.forename: Chong-bin
authors.initials: CB
authors.lastname: Liu
authors.forename: Zhi-feng
authors.initials: ZF
authors.lastname: Tian
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D019833:Genistein / Q000494:pharmacology*; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism
chemical_list: D002316:Cardiotonic Agents; D019833:Genistein; D000242:Cyclic AMP; D011505:Protein-Tyrosine Kinases