Abstract: AIM: To investigate the effects of different reactive oxygen species on the resting tension of porcine coronary arterial rings and to identify the effects of GEN and EST on ROS-elicited vasoconstriction.METHODS: Porcine coronary rings were prepared and then mounted in the organ bath.After an equilibration period, the changes treated with the drugs were observed.RESULTS: Rings with intact-endothelium appeared an obvious contraction after treatment with O2 ·-whereas endothelium-denuded rings had no effects.H₂O₂ induced a fast and transient contraction in the endothelium-denuded rings and failed in intact-endothelium rings.1 μmol·L^-1GEN significantly inhibited contractile response evoked by O2 ·-.In contrast with GEN, 1 μmol·L^-1EST had no effects.30 μmol·L^-1GEN markedly attenuated the contraction elicited by H₂O₂.CONCLUSION: GEN has distinct inhibitive effect on vasoconstriction induced by O₂^·-and H₂O₂, and its action is obviously superior to that in EST.

Key words: genistein, estradiol, vascular arterial tension, reactive oxygen species, coronary artery