Effects of genistein on contractility of isolated right ventricular muscles in guinea pig / 中国应用生理学杂志

ABSTRACT

<p><b>AIM</b>To study the effect of genistein (GEN) on contractility of isolated right ventricular muscles in guinea pig and its mechanisms.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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)).</p><p><b>CONCLUSION</b>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.</p>