Effect of estrogen on flow-induced dilation in NO deficiency: role of prostaglandins and EDHF.
To investigate the role of estrogen in flow-induced dilation (FiD) in nitric oxide (NO) deficiency, FiD was examined in isolated gracilis arterioles of ovariectomized (OVX) and OVX rats with estrogen replacement (OVE). Both groups of rats were treated chronically with N(omega)-nitro-L-arginine methyl ester. Plasma concentration of NO(2)/NO(3) was reduced in both groups. Plasma concentration of estradiol was lower in OVX than in OVE rats. FiD was similar in vessels of the two groups; calculated wall shear stress and basal tone were significantly greater in OVX vs. OVE rats. Indomethacin did not affect FiD in vessels from OVE rats but abolished dilation in vessels from OVX rats. Valeryl salicylate or NS-398 inhibited FiD by approximately 50%, whereas their simultaneous administration eliminated the response in arterioles from OVX rats. In vessels from OVE rats, miconazole or charybdotoxin eliminated FiD. Thus, in NO deficiency, prostaglandins derived from both cyclooxygenase isoforms mediate FiD in gracilis arterioles of OVX rats. Estrogen replacement switches the mediation, showing dependence on endothelium-derived hyperpolarizing factor in the arterioles of OVE rats.
Huang
A
A
Department of Physiology, New York Medical College, Valhalla, NY 10595, USA. An_Huang@nymc.edu
Wu
Y
Y
Sun
D
D
Koller
A
A
Kaley
G
G
D000818:Animals; D001160:Arterioles / Q000502:physiology; D001685:Biological Factors / Q000502:physiology*; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000097:blood; D004967:Estrogens / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D007527:Isoenzymes / Q000502:physiology; D008565:Membrane Proteins; D018482:Muscle, Skeletal / Q000098:blood supply*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000172:deficiency*; D010052:Ovariectomy; D011451:Prostaglandin-Endoperoxide Synthases / Q000502:physiology; D011453:Prostaglandins / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D001685:Biological Factors; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D004967:Estrogens; D007527:Isoenzymes; D008565:Membrane Proteins; D011453:Prostaglandins; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; D004958:Estradiol; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496513:Ptgs1 protein, rat; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin