Estrogen-induced augmentation of endothelium-dependent nitric oxide-mediated vasodilation in isolated rat cerebral small arteries. 2003

Hiroki Momoi, and Fumitaka Ikomi, and Toshio Ohhashi
The 1st Department of Physiology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621 Japan.

We examined chronic effects of 17beta-estradiol (E(2)beta) on the responses of isolated rat anterior cerebral small arteries to vasoactive substances with special reference to endothelial function. Female Sprague-Dawley rats were separated into four groups: (1) sham-operated group (Sham), (2) sham-operated plus E(2)beta treated group (Sham+E), (3) ovariectomized group (OVX), (4) ovariectomized plus E(2)beta treated group (OVX+E). 5-Hydroxytryptamine (5-HT) (10(-10)-10(-3) M) and U46619 (10(-15)-10(-8) M) induced concentration-dependent contractions in the cerebral small arteries. The 5-HT- and U46619-induced contractions were not affected by pretreatment with 3 x 10(-5) M N(omega)-nitro-L-arginine methyl ester (L-NAME). No significant difference in high potassium (80 mM)- and the agonists-mediated contractions was observed among the four groups. Administration of acetylcholine (ACh) (10(-9)-10(-3) M) and sodium nitroprusside (SNP) (10(-8)-10(-3) M) caused dose-related relaxations in the cerebral small arteries precontracted by 10(-8) M U46619. Chronic treatment with E(2)beta caused a significant potentiation of the ACh-induced relaxations in the Sham+E and OVX+E groups. The dose-response curve for ACh in the OVX group was quite similar to that obtained with the Sham group. The ACh-induced relaxation was reduced significantly by pretreatment with 3 x 10(-5) M L-NAME, and an additional treatment with 10(-3) M L-arginine reversed significantly the L-NAME-induced inhibition. The removal of endothelial cells produced a significant reduction of the ACh-induced relaxation. Indomethacin (10(-5) M) did not alter the ACh-induced relaxation. The findings suggest that E(2)beta potentiates ACh-induced endothelium-dependent relaxation in rat anterior cerebral arteries and that the potentiation may be, in part, mediated by increasing production and release of endogenous NO from the endothelial cells.

UI MeSH Term Description Entries
D009569 Nitric Oxide A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP. Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D010052 Ovariectomy The surgical removal of one or both ovaries. Castration, Female,Oophorectomy,Bilateral Ovariectomy,Bilateral Ovariectomies,Castrations, Female,Female Castration,Female Castrations,Oophorectomies,Ovariectomies,Ovariectomies, Bilateral,Ovariectomy, Bilateral
D002536 Cerebral Arteries The arterial blood vessels supplying the CEREBRUM. Arteries, Cerebral,Artery, Cerebral,Cerebral Artery
D004730 Endothelium, Vascular Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components. Capillary Endothelium,Vascular Endothelium,Capillary Endotheliums,Endothelium, Capillary,Endotheliums, Capillary,Endotheliums, Vascular,Vascular Endotheliums
D004791 Enzyme Inhibitors Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D004958 Estradiol The 17-beta-isomer of estradiol, an aromatized C18 steroid with hydroxyl group at 3-beta- and 17-beta-position. Estradiol-17-beta is the most potent form of mammalian estrogenic steroids. 17 beta-Estradiol,Estradiol-17 beta,Oestradiol,17 beta-Oestradiol,Aerodiol,Delestrogen,Estrace,Estraderm TTS,Estradiol Anhydrous,Estradiol Hemihydrate,Estradiol Hemihydrate, (17 alpha)-Isomer,Estradiol Monohydrate,Estradiol Valerate,Estradiol Valeriante,Estradiol, (+-)-Isomer,Estradiol, (-)-Isomer,Estradiol, (16 alpha,17 alpha)-Isomer,Estradiol, (16 alpha,17 beta)-Isomer,Estradiol, (17-alpha)-Isomer,Estradiol, (8 alpha,17 beta)-(+-)-Isomer,Estradiol, (8 alpha,17 beta)-Isomer,Estradiol, (9 beta,17 alpha)-Isomer,Estradiol, (9 beta,17 beta)-Isomer,Estradiol, Monosodium Salt,Estradiol, Sodium Salt,Estradiol-17 alpha,Estradiol-17beta,Ovocyclin,Progynon-Depot,Progynova,Vivelle,17 beta Estradiol,17 beta Oestradiol,Estradiol 17 alpha,Estradiol 17 beta,Estradiol 17beta,Progynon Depot
D004967 Estrogens Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Estrogen,Estrogen Effect,Estrogen Effects,Estrogen Receptor Agonists,Estrogenic Agents,Estrogenic Compounds,Estrogenic Effect,Estrogenic Effects,Agents, Estrogenic,Agonists, Estrogen Receptor,Compounds, Estrogenic,Effects, Estrogen,Effects, Estrogenic,Receptor Agonists, Estrogen
D005260 Female Females
D000109 Acetylcholine A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system. 2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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