RESUMEN
<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>
Asunto(s)
Animales , Masculino , Cardiotónicos , Farmacología , AMP Cíclico , Metabolismo , Genisteína , Farmacología , Cobayas , Ventrículos Cardíacos , Técnicas In Vitro , Contracción Miocárdica , Proteínas Tirosina Quinasas , MetabolismoRESUMEN
<p><b>AIM</b>To select higher thrombolytic and lower toxic single component of earthworm fibrinolytic enzymes (EFE).</p><p><b>METHODS</b>EFE containing total components were obtained by affinity chromatography from Eisenia fetida. Using ion-exchange chromatography to separate three main components EfP-0-2, EfP-I-1 and EfP-I-2 from EFE, their thrombolytic activity and toxicity were compared with EFE.</p><p><b>RESULTS</b>Among these components, EfP-I-1 had higher thrombolytic activity in vitro. When 4.5 mg x kg(-1) of these components were injected, the contents of fibrinogen in rat serum were not affected, but only EfP-I-1 exhibited distinct thrombolytic activity. When 6.0 mg x kg(-1) of them were injected intravenously, the bleeding time was not evidently delayed only by EfP-I-1. The acute toxicity test showed that the LD50 of EfP-I-1 was higher than EFE by 2. 17 times.</p><p><b>CONCLUSION</b>Because of distinct thrombolytic activity, lower toxicity in vivo, higher content in EFE and easy to purify, EfP-I-1 was adapted to be developed as a single component medicine for treating thrombus.</p>