Responses of isolated perfused uterine vascular beds of nonpregnant and pregnant rats to endogenous and exogenous nitric oxide.
The responses to endothelial vasodilators and exogenous nitric oxide (NO) were characterized in intact isolated uterine vascular beds of nonpregnant, midpregnant and late-pregnant rats perfused with Kreb's buffer (37 degrees C, 5% CO(2) in air, pH approximately 7.4) containing 2% dextran and indomethacin. Phenylephrine increased perfusion pressure in the vascular beds equally in all three groups. In the presence of phenylephrine, N(omega)-nitro-L-arginine methyl ester (L-NAME) significantly augmented perfusion pressure in the order: nonpregnant<midpregnant<late-pregnant uterine vascular bed. Acetylcholine and bradykinin-induced attenuation of perfusion pressure did not depend on gestational age. The decrease in perfusion pressure induced by acetylcholine was nonsignificantly attenuated by L-NAME in vascular beds from pregnant rats. The attenuation induced by bradykinin reached significant level in the vascular beds from midpregnant rats. The diethylamine (DEA)/NO-induced decrease in perfusion pressure was not influenced by L-NAME in any group. These data demonstrate the augmentation of basal release of NO associated with progression of pregnancy, while the responses to endothelial vasodilators do not depend on gestational age and are not abolished by inhibition of NO synthase, suggesting involvement of nonprostanoid non-NO factor in the control of uterine circulation.
Fulep
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Division of Reproductive Sciences, Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston, TX 77555-1062, USA. yverderni@utmb.edu
Vedernikov
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YP
Saade
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GR
Garfield
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RE
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001685:Biological Factors / Q000502:physiology; D001920:Bradykinin / Q000494:pharmacology; D004048:Diethylamines / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology* / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D021041:Placental Circulation / Q000187:drug effects*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D014599:Uterus / Q000098:blood supply* / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D001685:Biological Factors; D004048:Diethylamines; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; C067410:endothelium-dependent hyperpolarization factor; D009569:Nitric Oxide; C034281:diethylamine; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester