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Epithelial Sodium Channel in the Human Syncytiotrophoblast
DEL MÓNACO, S.; ASSEF, Y.; DAMIANO, A.; ZOTTA, E.; IBARRA, C.; KOTSIAS, B.
Simposio; II Simposio Latino Americano sobre Interacción Materno-Fetal Placenta; 2005
International Federation of Placenta Associations
The syncytiotrophoblast (SCT) of placenta regulates the transport of solutes and water between maternal and fetal blood. This transport involves movement of Na+ and its contribution to the osmotic pressure is an important determinant of the extracellular fluid volume. The aim of this work was to detect and characterize the Epithelial Sodium Channel (ENaC) in human SCT from normal and preeclamptic placentas. ENaC is associated with hypertensive disorders when its expression is deregulated in absorptive epithelia. Methods: We carried out studies using RTPCR, western blot and immunohistochemistry in normal and preeclamptic placenta. We also detected ENaC in the BeWo cell line (a human SCT model) and we studied the sodium currents generated in these cells with patch clamp. Results: á, â and ã-ENaC subunits are present in the apical membrane of the human SCT although á-ENaC subunit has a reduced expression in preeclamptic placentas. In BeWo cells, ENaC is modulated by aldosterone, vasopressin, estradiol and progesterone. Aldosterone (100 nM, 12 hs) induces a 20-fold increment in an AMPc-activated amiloride-sensitive current (p