Document Detail


Large chloride channel from pre-eclamptic human placenta.
MedLine Citation:
PMID:  13129687     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Chloride transport involving conductive pathways participates in numerous epithelial functions, such as membrane voltage maintenance, solute transport and cell volume regulation. Evidence points to involvement of transepithelial chloride transport in such functions in placental syncytiotrophoblast. A molecular candidate for physiologic conductive chloride transport in apical syncytiotrophoblast membrane is a Maxi-chloride channel with distinct biophysical properties: conductance over 200 pS, multiple substates, voltage dependent open probability, and permeation to anionic amino acids. Pre-eclampsia, a high incidence pathology of pregnancy, exerts great impact on fetal morbi-mortality. This relies, among others, on intrauterine growth restriction (IUGR), thought to be mediated by diminished blood flow to the placenta, with growing knowledge regarding contribution of other factors. The Maxi-chloride channel's properties suggest it could be altered in this pathology. We have characterized the apical chloride channels from pre-eclamptic placentae, reconstituted in giant liposomes suitable for patch-clamp electrophysiological studies. In n=33 experiments from n=6 pre-eclamptic placentae we observed a chloride-permeable channel with similar biophysical properties to the channel from normal tissue (n=29 experiments from n=15 placentae). However, the main conductance state showed diminished magnitude (<150 pS), and the open probability versus voltage relationship exhibited a flattened curve instead of the bell-shaped curve of normal placentae. These results are the first evidence of a functionally altered ionic channel from placental syncytiotrophoblast in pre-eclampsia. Considering the abundance of chloride-conducting channel activity in human apical membrane and their relevance in epithelial function in general, these alterations could greatly disturb numerous placental functions that rely on syncytiotrophoblast integrity.
Authors:
L Bernucci; F Umaña; P Llanos; G Riquelme
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Placenta     Volume:  24     ISSN:  0143-4004     ISO Abbreviation:  Placenta     Publication Date:    2003 Sep-Oct
Date Detail:
Created Date:  2003-09-17     Completed Date:  2004-05-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8006349     Medline TA:  Placenta     Country:  England    
Other Details:
Languages:  eng     Pagination:  895-903     Citation Subset:  IM    
Affiliation:
Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Universidad de Chile, Casilla 70005, 7 Santiago, Chile.
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MeSH Terms
Descriptor/Qualifier:
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
Area Under Curve
Chloride Channels / antagonists & inhibitors,  metabolism*
Electric Conductivity
Female
Humans
Kinetics
Liposomes
Membrane Potentials
Patch-Clamp Techniques
Placenta / metabolism*
Pre-Eclampsia / metabolism*
Pregnancy
Chemical
Reg. No./Substance:
0/Chloride Channels; 0/Liposomes; 53005-05-3/4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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