Linked Life Data

3174387

Source:http://linkedlifedata.com/resource/pubmed/id/3174387

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1988-11-7
pubmed:abstractText
Uptake studies with 22Na were performed in cultured bovine pigmented ciliary epithelial cells, in order to characterize mechanisms of Na+ transport. A large part of Na+ uptake was sensitive to amiloride, quinidine and harmaline. Na+ uptake was stimulated by intracellular acidification (using the NH+4 prepulse technique), and was inhibited with increasing extracellular proton concentration. Decreasing extracellular pH from 7.5 to 7.0 increased the apparent KM for Na+ from 38 to 86 mM without considerable changes in Vmax. In the presence of 5 mM Na+ half maximal inhibition of amiloride sensitive Na+ uptake by extracellular protons was observed at a hydrogen concentration of 50 nM. In the presence of 50 mM Na+ the proton concentration necessary for 50% inhibition was 139 nM. Thus, the mode of inhibition of extracellular H+ seemed to be competitive with a Ki of 20-40 nM. 10 microM amiloride increased the apparent KM for Na+ from 33 mM to 107 mM, while Vmax remained nearly unchanged. IC50 for amiloride was 6 microM at 5 mM Na+ and 36 microM in the presence of 150 mM Na+. Thus, amiloride behaves as a competitive inhibitor with a Ki of about 5 microM. The affinities of Na+ to the transport site (KM approximately 16 mM), to the inhibitory site for protons (KM approximately 21 mM), and to the inhibitory site for amiloride (KM approximately 26 mM) were in the same order of magnitude. In summary, we have presented evidence for the presence of a Na+/H+ exchanger in cultured bovine pigmented ciliary epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
412
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
80-5
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Kinetic properties of Na+/H+ exchange in cultured bovine pigmented ciliary epithelial cells.
pubmed:affiliation
Institut für Klinische Physiologie, Klinikum Steglitz der Freien Universität Berlin.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't