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This study was conducted to determine whether gestational changes in maternal uterine artery reactivity are primarily driven by local vs. systemic factors. Rats underwent surgical ligation of one oviduct, thereby restricting implantation and pregnancy to one uterine horn while maintaining a gestational endocrine milieu. Uterine arcuate arteries were isolated and cannulated to evaluate reactivity. Vessels from the implanted horn were significantly more sensitive to phenylephrine and less sensitive to sodium nitroprusside than those from the non-implanted horn; endothelial basal calcium levels were only increased in the implanted horn. Conversely, there were no differences in sensitivity to acetylcholine, or its effects on endothelial cell calcium, although efficacy was greater in vessels from the implanted vs. non-implanted horn. These findings demonstrate that local factors are predominant in inducing changes in vascular smooth muscle function, while endothelial adaptations result from an interplay between local and systemic factors, with distinct effects attributable to each. [ABSTRACT FROM PUBLISHER]

Objective: To investigate the influence of uterine artery embolization (UAE) on fertility after bilateral UAE with either tris-acryl gelatin microspheres (TAGM) or gelatin particles (GP). Materials and Methods: Six ewes that underwent UAE with TAGM, 6 ewes that underwent UAE with GP, and 6 control ewes were compared. After hormonal synchronization of the menstrual cycle, artificial insemination (AI) was performed. When pregnancy did not result, ewes were naturally inseminated. Results: After AI, progesterone concentrations in blood increased and were maintained at >1.0 ng/mL in 9 ewes (3 per group). Three ewes became pregnant after AI. The abortion rate was higher in the UAE group. The remaining 15 sheep were naturally inseminated, with 14 delivering 15 lambs. Mean period of term gestation in UAE group ewes was 155.7 versus 158.6 days in control group ewes. Lambs' body weight, body length, and withers height after birth did not differ between those from UAE group and control group. Lambs from ewes embolized with GP tended to be smaller and had lower body weight than those from other groups. Conclusion: Uterine artery embolization influenced reproductive ability in sheep and UAE with GP could lead to intrauterine growth retardation. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of chronic blockade of nitric oxide (NO) production and endothelin (ET-1) receptor antagonism on edothelial and vascular smooth muscle function of the uterine artery in vitro obtained from nonpregnant and pregnant rats.Methods:Pregnant or nonpregnant Wistar rats wee either treated orally for up to 18 days with the NO synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME), the ETA-/ETB-receptor antagonist bosentan, or both, or they received no treatment (controls). Absolute contractile force as well as endothelium-dependent and -independent vascular reactivity of uterine arteries were determined in vitro. Isometric tension was recorded. ANOVA and the Mann-Whitney U test were used for statistical analysis.Results:Pregnancy increased obsolute tension (mN/mm) elicited in uterine arteries by ET-1 (P < .01), serotonin (P < .05), norepinephrine (P < .02), and KCl (P < .0001). Chronic treatment with L-NAME or L-NAME plus bosentan, but not with bosentan alone, reduced contractions to KCl in pregnant and nonpregnant rats (P < .005-.0001), while pregnancy-induced enhancement in tension development remained unchanged in all groups (P < .005). After exposure of uterine arteries to L-NAME in vitro, vascular sensitivity to ET-1 was augmented in uterine arteries of pregnant but not of nonpregnant animals (P < .05).L-NAME-pretreatmetn did not influence the pregnancy-induced increase of vascular sensitivity to acetylcholine but reduced maximal relaxation in nonpregnant animals (P < .05). In addition, pregnancy diminished sensitivity of uterine arteries to sodium nitroprusside (P < .002), which was abolished by chronically administered L-NAME. Bosentan had no influence on vasodilation in vitro.Conclusion:Neither endothelin-1 nor nitric oxide seem to contribute to the augmented tension to depolarization and receptor-operated stimulation of vascular smooth muscle cells in rat uterine arteries during pregnancy. In addition, pregnancy is associated with increased NO production in uterine arteries, as evidenced by augmented endothelium-dependent relaxations, increased NO release by endothelin-1, and decreased sensitivity to sodium nitroprusside. [ABSTRACT FROM PUBLISHER]