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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Pt 1
pubmed:dateCreated
1989-11-21
pubmed:abstractText
Cytoplasmic pH (pHi) was monitored using the pH-sensitive absorbance of 5(6)carboxy-4',5'-dimethylfluorescein in monolayers of a cell clone derived from bovine pigmented ciliary epithelium (PE) transformed with the simian virus 40. 1) Changing extracellular media from a nominally HCO3(-)-free solution to a solution containing 28 mM HCO3(-)-5% CO2 at constant extracellular pH (7.4) resulted in a delayed alkalinization of pHi, which was 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) sensitive and was inhibited in Na+-free medium and in Cl(-)-depleted cells. 2) DIDS pretreatment acidified pHi in HCO3(-)-containing media. 3) Replacing extracellular Cl- resulted in a DIDS-sensitive, HCO3(-)-dependent, and Na+-independent alkalinization. 4) Replacing extracellular Na+ in HCO3(-)-containing media led to a partly DIDS-sensitive intracellular acidification. 5) Recovery of pHi after an alkali load (acetate prepulse) had a HCO3(-)-dependent and DIDS-sensitive component. 6) Two Na+-dependent components participated in pHi regulation after an acid load (NH4+ prepulse) in HCO3(-)-containing solution. One was amiloride sensitive, the other was DIDS sensitive and was inhibited in HCO3(-)-free media and after Cl- depletion. We conclude that in cultured PE, in addition to Na+-H+ exchange, two HCO3-transporters participate in pHi regulation. Cl(-)-dependent Na+-HCO3-symport regulates pHi during steady state and after an acid load, and Na+-independent Cl(-)-HCO3-exchange is involved in pHi recovery after an alkali load.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
257
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C696-705
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Role of HCO3- in regulation of cytoplasmic pH in ciliary epithelial cells.
pubmed:affiliation
Institut für Klinische Physiologie, Klinikum Steglitz der Freien Universität Berlin, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't