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Effects of phytoestrogen genistein on delayed afterdepolarization and triggered activity induced by ouabain in guinea pig papillary muscles

Ma Tao, He Ruirong, Wang Chuan

Department of Physiology,Institute of Basic Medicine,Hebei Medical University.Shijiazhuang 050017,Hebei；China

Abstract

The results are as follows: (1) DAD and TA induced by ouabain (1 #mu#mol/L) were makedly inhibited by pretreatment with GST (10, 50, 100 #mu#mol/L) in a concentration-dependent manner. (2) NG-nitro-L-arginine methyl ester (L-NAME, 1 mmol/L), an NO synthase inhibitor, failed to affect the above effects of GST. (3) 5 #mu#mol/L 17 #beta#-estradiol (E_(2)) or 10 #mu#mol/L GST alone showed no effects on DAD and TA, whereas GST combined with E_(2) at the same doses exerted significant inhibitory effects on DAD and TA. Since GST is known to reduce the calcium influx, it is suggested that GST might have antiarrhythmic effects, possibly by reducing calcium influx. The antiarrhythmic effects of GST may contribute to its cardioprotective action.

Key words: Phytoestrogen;genistein;Delayed afterdepolarization;Papillary muscles;Electrophysiology;Ouabain;17#beta#-estradiol

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Citing This Article：

Ma Tao, He Ruirong, Wang Chuan. Effects of phytoestrogen genistein on delayed afterdepolarization and triggered activity induced by ouabain in guinea pig papillary muscles. Acta Physiol Sin 2002; 54 (5): (in Chinese with English abstract).