The influence of pregnancy on endothelium-derived nitric oxide mediated relaxations in isolated human resistance vessels.
Pregnancy is associated with drastic hemodynamic adaptations, including a decrease in peripheral resistance. Vascular resistance is substantially influenced by endothelium-derived nitric oxide (NO). This study was designed to investigate whether pregnancy might influence endothelium-derived NO-mediated relaxations in human resistance arteries. Reactivity of isolated human subcutaneous arteries, dissected out of abdominal fat from women who underwent a laparotomy or cesarean section, was studied using a small vessel myograph. Addition of acetylcholine (1 nM-10 microM) or bradykinin (1 nM-10 microM) to precontracted preparations elicited concentration-dependent relaxation responses that were dependent on the presence of the endothelium and were partially inhibited by the NO-synthase inhibitor nitro-L-arginine (0.1 mM). The relaxations to acetylcholine and bradykinin were similar in vessels isolated from pregnant and non-pregnant women. Nitro-L-arginine (0.1 mM) had no influence on basal tone and had a similar inhibitory influence on the endothelium-mediated relaxations in vessels from non-pregnant and pregnant women. These results indicate that the influence of endothelium-derived NO in human subcutaneous resistance arteries is not altered at the end of pregnancy.
Van de Voorde
J
J
Department of Physiology and Physiopathology, University of Gent, Belgium.
Depypere
H
H
Vanheel
B
B
D000109:Acetylcholine / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006801:Humans; D009126:Muscle Relaxation / Q000187:drug effects*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D019335:Nitroarginine / Q000494:pharmacology*; D011247:Pregnancy / Q000502:physiology*; D014655:Vascular Resistance / Q000187:drug effects*
D019335:Nitroarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D001920:Bradykinin