Linked Life Data

11238004

Source:http://linkedlifedata.com/resource/pubmed/id/11238004

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2001-3-12
pubmed:abstractText
Alveolar fluid clearance in the developing and mature lungs is believed to be mediated by some form of epithelial Na channels (ENaC). However, single-channel studies using isolated alveolar type II (ATII) cells have failed to demonstrate consistently the presence of highly selective Na+ channels that would be expected from ENaC expression. We postulated that in vitro culture conditions might be responsible for alterations in the biophysical properties of Na+ conductances observed in cultured ATII cells. When ATII cells were grown on glass plates submerged in media that lacked steroids, the predominant channel was a 21-pS nonselective cation channel (NSC) with a Na+-to-K+ selectivity of 1; however, when grown on permeable supports in the presence of steroids and air interface, the predominant channel was a low-conductance (6.6 +/- 3.4 pS, n = 94), highly Na+-selective channel (HSC) with a P(Na)/P(K) >80 that is inhibited by submicromolar concentrations of amiloride (K(0.5) = 37 nM) and is similar in biophysical properties to ENaC channels described in other epithelia. To establish the relationship of this HSC channel to the cloned ENaC, we employed antisense oligonucleotide methods to inhibit the individual subunit proteins of ENaC (alpha, beta, and gamma) and used patch-clamp techniques to determine the density of this channel in apical membrane patches of ATII cells. Overnight treatment of cells with antisense oligonucleotides to any of the three subunits of ENaC resulted in a significant decrease in the density of HSC channels in the apical membrane cell-attached patches. Taken together, these results show that when grown on permeable supports in the presence of steroids and air interface, the predominant channels expressed in ATII cells have single-channel characteristics resembling channels that are associated with the coexpression of the three cloned ENaC subunits alpha-, beta-, and gamma-ENaC.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1040-0605
pubmed:author
pubmed:issnType
Print
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
L646-58
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Expression of highly selective sodium channels in alveolar type II cells is determined by culture conditions.
pubmed:affiliation
Department of Pediatrics, Emory University School of Medicine, 2040 Ridgewood Dr., Atlanta, GA 30322, USA. ljain@emory.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't