Action of genistein on tension of isolated rabbit femoral artery and its mechanism.
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.
Ji
En-Sheng
ES
Department of Physiology, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, China.
Li
Qing
Q
He
Rui-Rong
RR
D000818:Animals; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D005263:Femoral Artery / Q000187:drug effects* / Q000502:physiology*; D019833:Genistein / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D011817:Rabbits; D014664:Vasodilation / Q000187:drug effects
D020746:Calcium Channels, L-Type; D009569:Nitric Oxide; D019833:Genistein