title: Chronic treatment with 17beta-estradiol increases susceptibility of smooth muscle cells to nitric oxide.
abstract: The purpose of this study was to evaluate the role of estrogen as a vasodilator or relaxing modulator during vascular tonus through chronic estrogen treatment. Experiments were conducted using isolated basilar arteries from ovariectomized female rabbits divided into two groups (the with and without estrogen replacement groups, respectively). Both acetylcholine and carbachol relaxed the basilar arteries of rabbits in the with estrogen replacement group (pre-contracted by 30 mM K(+)) more strongly than in the without estrogen replacement group. Vasodilatation effects of (+/-)-(E)-4-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3 -hexenamide (NOR1) and S-nitroso-N-acetyl-penicillamine (SNAP) were greater in rabbits in the with estrogen replacement group than the without estrogen replacement both with endothelium-intact and denuded preparations. On the other hand, vasodilatation effects of nicardipine, 17beta-estradiol and membrane-permeable cyclic-GMP or cyclic-AMP were the same in both groups. These results suggest that chronic administration of estradiol potentiates reactivity to nitric oxide (NO) in smooth muscle cells, which could be a therapeutic target for cardiovascular diseases in postmenopausal women.
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, Kyushu University, 3-1-1 Maedashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Rika
authors.initials: R
authors.lastname: Egami
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nozaki
authors.forename: Keiko
authors.initials: K
authors.lastname: Koera
authors.forename: Akiko
authors.initials: A
authors.lastname: Okuma
authors.forename: Hitoo
authors.initials: H
authors.lastname: Nakano
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy; D005260:Female; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D009574:Nitro Compounds / Q000494:pharmacology; D010052:Ovariectomy; D011188:Potassium; D011817:Rabbits; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology; D014662:Vasoconstrictor Agents; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D009574:Nitro Compounds; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C101316:methyl-2-hydroxyimino-5-nitro-6-methoxy-3-hexeneamide; D009569:Nitric Oxide; D004958:Estradiol; D026423:S-Nitroso-N-Acetylpenicillamine; D002217:Carbachol; D000109:Acetylcholine; D011188:Potassium