Action of genistein on tension of isolated rabbit femoral artery and its mechanism / 生理学报

ABSTRACT

The phytoestrogen genistein has been shown to relax agonist-preconstricted arteries in vitro, the mechanism of this relaxation remains incompletely understood. The present study aimed to investigate the effect of phytoestrogen genistein on the tension of rabbit femoral arteries in vitro and to determine the mechanism of such relaxation. The results are as follows (1) genistein (10~40 micromol/L) relaxed femoral arterial rings in a concentration-dependent manner under the condition of precontraction induced by phenylephrine (PE, 1 micromol/L); (2) removal of the endothelium significantly inhibited genistein-induced relaxation; (3) pretreatment with NOS inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 100 micromol/L) also significantly inhibited this relaxation by genistein, implying that the concentration-dependent vasorelaxation caused by genistein is endothelium-dependent and involved nitric oxide; and (4) pretreatment with an L-type calcium channel agonist, Bay K 8644 (0.5 micromol/L), also significantly inhibited the genistein-induced relaxation in both endothelium-intact and endothelium-denuded rings. The results suggest that the genistein-induced vascular relaxation of these rabbit arteries is partially endothelium-dependent and involves calcium antagonistic mechanism.