Linked Life Data

10552013

Source:http://linkedlifedata.com/resource/pubmed/id/10552013

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1999-12-10
pubmed:abstractText
We studied the relationship between changes in intracellular pH (pH(i)), intracellular Ca(2+)([Ca(2+)](i)) and charybdotoxin sensitive (CTX) maxi-K(+) channels occurring after modest 'physiological' swelling in guinea pig jejunal villus enterocytes. Villus cell volume was assessed by electronic cell sizing, and pH(i) and [Ca(2+)](i) by fluorescence spectroscopy with 2,7, biscarboxyethyl-5-6-carboxyfluorescein and Indo-1, respectively. In a slightly (0.93 x isotonic) hypotonic medium, villus cells swelled to the same size they would reach during d-glucose or l-alanine absorption; the subsequent Regulatory Volume Decrease (RVD) was prevented by CTX. After the large volume increase in a more hypotonic (0.80 x isotonic) medium, RVD was unaffected by CTX. After modest swelling associated with 0.93 x isotonic dilution, the pH(i) alkalinized but N-5-methyl-isobutyl amiloride (MIA) prevented this DeltapH(i) and the subsequent RVD. Even in the presence of MIA, alkalinization with added NH(4)Cl permitted complete RVD which could be inhibited by CTX. The rate of (86)Rb efflux which also increased after this 0.93 x isotonic dilution was inhibited an equivalent amount by CTX, MIA or Na(+)-free medium. Modest swelling transiently increased [Ca(2+)](i) and Ca(2+)-free medium or blocking alkalinization by MIA or Na(+)-free medium diminished this transient increase an equivalent amount. RVD after modest swelling was prevented in Ca(2+)-free medium but alkalinization still occurred. After large volume increases, alkalinization of cells increased [Ca(2+)](i) and volume changes became sensitive to CTX. We conclude that both alkalinization of pH(i) and increased [Ca(2+)](i) observed with 'physiological' volume increase are essential for the activation of CTX-sensitive maxi-K(+) channels required for RVD.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-2631
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
172
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
47-58
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Increases in intracellular pH and Ca(2+) are essential for K(+) channel activation after modest 'physiological' swelling in villus epithelial cells.
pubmed:affiliation
Department of Pediatrics, McGill University-Montreal Children's Hospital Research Institute, Montreal, Quebec, Canada.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't