OBJECTIVE: We evaluated the role of endothelium-derived nitric oxide and endothelin 1 in the modulation of myogenic tone, norepinephrine-induced tone, and flow-mediated responses in resistance arteries from pregnant women at term. STUDY DESIGN: Arteries (approximately 200 microm at 50 mm Hg; n = 27) were dissected from myometrial biopsies obtained from women undergoing elective cesarean delivery at term and mounted in a pressure arteriograph. Responses to intraluminal flow, pressure, and norepinephrine were studied in the absence and presence of the nitric oxide synthase inhibitor Nomega-nitro-L-arginine and the endothelin-converting enzyme inhibitor phosphoramidon. RESULTS: Pressure-induced (80 mm Hg) myogenic tone was significantly enhanced after incubation with Nomega-nitro-L-arginine (33% +/- 8% vs 24% +/- 4%; P <.05), whereas phosphoramidon significantly reduced myogenic tone (24% +/- 5% vs 33% +/- 5%; P <.05). A combination of Nomega-nitro-L -arginine and phosphoramidon did not affect myogenic tone. Norepinephrine-induced tone was significantly enhanced after nitric oxide synthase inhibition (49% +/- 6% vs 41% +/- 5%; P <.05) but was not affected by phosphoramidon. Flow-mediated dilatation was increased in the presence of phosphoramidon compared with flow-induced dilatation in physiologic salt solution (maximum dilatation, 57% +/- 12% vs 30% +/- 5%; analysis of variance, P <.05), and all flow-induced dilatation was abolished by Nomega-nitro-L -arginine. CONCLUSIONS: Nitric oxide and endothelin 1 may play a significant role in modulation of myogenic tone and flow-mediated responses in the resistance vasculature of the uterine circulation in normal pregnancy.
OBJECTIVE: We evaluated the role of endothelium-derived nitric oxide and endothelin 1 in the modulation of myogenic tone, norepinephrine-induced tone, and flow-mediated responses in resistance arteries from pregnant women at term. STUDY DESIGN: Arteries (approximately 200 microm at 50 mm Hg; n = 27) were dissected from myometrial biopsies obtained from women undergoing elective cesarean delivery at term and mounted in a pressure arteriograph. Responses to intraluminal flow, pressure, and norepinephrine were studied in the absence and presence of the nitric oxide synthase inhibitor Nomega-nitro-L-arginine and the endothelin-converting enzyme inhibitor phosphoramidon. RESULTS: Pressure-induced (80 mm Hg) myogenic tone was significantly enhanced after incubation with Nomega-nitro-L-arginine (33% +/- 8% vs 24% +/- 4%; P <.05), whereas phosphoramidon significantly reduced myogenic tone (24% +/- 5% vs 33% +/- 5%; P <.05). A combination of Nomega-nitro-L -arginine and phosphoramidon did not affect myogenic tone. Norepinephrine-induced tone was significantly enhanced after nitric oxide synthase inhibition (49% +/- 6% vs 41% +/- 5%; P <.05) but was not affected by phosphoramidon. Flow-mediated dilatation was increased in the presence of phosphoramidon compared with flow-induced dilatation in physiologic salt solution (maximum dilatation, 57% +/- 12% vs 30% +/- 5%; analysis of variance, P <.05), and all flow-induced dilatation was abolished by Nomega-nitro-L -arginine. CONCLUSIONS:Nitric oxide and endothelin 1 may play a significant role in modulation of myogenic tone and flow-mediated responses in the resistance vasculature of the uterine circulation in normal pregnancy.
Authors: Delrae M Eckman; Ridhima Gupta; Charles R Rosenfeld; Timothy M Morgan; Shelton M Charles; Heather Mertz; Lorna G Moore Journal: Am J Physiol Regul Integr Comp Physiol Date: 2012-06-27 Impact factor: 3.619
Authors: Antonio Malvasi; Antonella Vimercati; Ilaria Ricci; Nico Picardi; Ettore Cicinelli; Ioannis Kosmas; Giorgio Maria Baldini; Andrea Tinelli Journal: Int J Mol Sci Date: 2022-09-27 Impact factor: 6.208