Comparison of endothelium-derived relaxing factor activity between nonpregnant and pregnant rats.
The tension of isolated ring preparation of aorta from nonpregnant and pregnant rats was measured isometrically to study the effect of pregnancy on endothelium-derived relaxing factor activity. Contraction in response to norepinephrine and potassium chloride was greater in aortae from nonpregnant rats than in those from pregnant rats. The endothelium-dependent relaxation that was caused by acetylcholine (10(-10)-3 x 10(-9) M) in aortae precontracted with norepinephrine was significantly enhanced in aortae from pregnant rats compared with the relaxation in those from nonpregnant rats. NG-nitro-L-arginine methyl ester (L-NAME) inhibited the endothelium-dependent relaxation in both aorta from pregnant and nonpregnant rats. L-Arginine reversed the inhibition of L-NAME. Those results suggest that the enhanced endothelium-derived relaxing factor activity in rats aortae is associated with pregnancy.
Honda
H
H
Department of Pharmacology, Tokyo University of Pharmacy and Life Science, Japan.
Kaneko
H
H
Kondo
M
M
Kogo
H
H
D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002117:Calcitriol / Q000008:administration & dosage* / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004958:Estradiol / Q000097:blood; D005260:Female; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D000643:Ammonium Chloride; D009569:Nitric Oxide; D011374:Progesterone; D004958:Estradiol; D019001:Nitric Oxide Synthase; D002117:Calcitriol; D019331:NG-Nitroarginine Methyl Ester