Linked Life Data

10710550

Source:http://linkedlifedata.com/resource/pubmed/id/10710550

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-4-10
pubmed:abstractText
Functional and immunohistochemical studies were performed to localize and identify Na(+)/H(+) exchanger (NHE) isoforms in macula densa cells. By using the isolated perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, intracellular pH (pH(i)) was measured with fluorescence microscopy by using 2',7'-bis-(2-carboxyethyl)-5-(and -6) carboxyfluorescein. NHE activity was assayed by measuring the initial rate of Na(+)-dependent pH(i) recovery from an acid load imposed by prior lumen and bath Na(+) removal. Removal of Na(+) from the bath resulted in a significant, DIDS-insensitive, ethylisopropyl amiloride (EIPA)-inhibitable decrease in pH(i). This basolateral transporter showed very low affinity for EIPA and Hoechst 694 (IC(50) = 9.0 and 247 microM, respectively, consistent with NHE4). The recently reported apical NHE was more sensitive to inhibition by these drugs (IC(50) = 0.86 and 7.6 microM, respectively, consistent with NHE2). Increasing osmolality, a known activator of NHE4, greatly stimulated basolateral NHE. Immunohistochemical studies using antibodies against NHE1-4 peptides demonstrated expression of NHE2 along the apical and NHE4 along the basolateral, membrane, whereas NHE1 and NHE3 were not detected. These results suggest that macula densa cells functionally and immunologically express NHE2 at the apical membrane and NHE4 at the basolateral membrane. These two isoforms likely participate in Na(+) transport, pH(i), and cell volume regulation and may be involved in tubuloglomerular feedback signaling by these cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1931-857X
pubmed:author
pubmed:issnType
Print
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F452-63
pubmed:dateRevised
2011-4-28
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Macula densa Na(+)/H(+) exchange activities mediated by apical NHE2 and basolateral NHE4 isoforms.
pubmed:affiliation
Department of Medicine, Division of Nephrology and Nephrology Research and Training Center, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't