Key result
Endothelin-1 binds densely to human placental vessels, showing higher affinity in umbilical arteries than veins.
Why the study?
Endothelin-1 may regulate fetoplacental vascular resistance, but the localization and quantification of its binding sites in human placenta and umbilical vessels were not well characterized.
Answers are grounded in this paper and cite their sources.
The localization of Endothelin-1 binding sites in human placental and umbilical vessels supports its role as a paracrine-acting vasoconstrictor regulating fetoplacental hemodynamics.
Endothelin-1 (ET-1) has potent vasoconstrictor effects and thus may be involved in regulating fetoplacental vascular resistance. By using quantitative in vitro autoradiography, the 125I-ET-1 binding sites in human placentas and umbilical vessels were localized and quantified. A high density of specific 125I-ET-1 binding sites was found in the placental villi and vessels. In the media of umbilical vessels, affinity for the peptide was higher in arteries than in veins. In all structures, 125I-ET-1 binding was inhibited with unlabeled ET-1 in the picomolar range. Unrelated peptides such as oxytocin or atrial natriuretic peptide failed to compete for 125I-ET-1 binding. The localization of binding sites points to a regulation of hemodynamic functions of ET-1 on the fetal side of the placental circulation and supports evidence regarding ET-1 as a paracrine-acting vasoconstrictor.
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Rath et al. (2010) studied this question. 125I-Endothelin-1 vs. Unlabeled ET-1, oxytocin, atrial natriuretic peptide was evaluated on Localization and quantification of 125I-ET-1 binding sites. A high density of specific 125I-Endothelin-1 binding sites was localized in human placental villi and vessels, with higher affinity in umbilical arteries than veins.
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