Linked Life Data

12593669

Source:http://linkedlifedata.com/resource/pubmed/id/12593669

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-6-18
pubmed:abstractText
Disruption of cellular acid-base status alters the host defence functions of alveolar macrophages (m phi). These pH effects might be mediated by pH-sensitive changes in the signalling pathways of the effector functions of m phi. The present study examined the effects of intracellular pH (pH(i)) on the free cytosolic calcium concentration ([Ca(2+)](i)), an important second messenger for cell functions. [Ca(2+)](i) and pH(i) of rabbit resident alveolar m phi were measured using fluorescent dyes. With extracellular pH (pH(o)) of 7.4, the steady-state pH(i) and [Ca(2+)](i) were approx. 7.14 and 123 nM respectively. Incubation at pH(o) 6.8 caused a sustained cytosolic acidosis, but did not affect [Ca(2+)](i). Likewise, [Ca(2+)](i) was unchanged when m phi at pH(o) 7.4 were acidified using bafilomycin A(1) or sodium propionate. In contrast, [Ca(2+)](i) was markedly sensitive to cytosolic alkalosis. Exposure to NH(4)Cl at pH(o) 7.4 caused transient increases in both pH(i) and [Ca(2+)](i). The Ca(2+) response was mediated by release of intracellular Ca(2+) from thapsigargin-sensitive stores and was potentiated by capacitative entry of extracellular Ca(2+). Incubation at high pH(o) values (>7.4) produced sustained increases in pH(i) and [Ca(2+)](i). The sustained elevation of [Ca(2+)](i) was consistent with pH-sensitive inhibition of plasma-membrane Ca(2+)-ATPase. The response to high pH(o) was unaffected by blockade of L-type or receptor-operated Ca(2+) channels with nifedipine or SKF-96365, and was independent of extracellular Na(+). The findings indicate that pH impacts cytosolic Ca(2+) homoeostasis at multiple levels. The data suggest that cellular acid-base status can influence Ca(2+)-dependent signalling events in resident alveolar m phi, especially during alkaline disruptions of pH(i).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0143-5221
pubmed:author
pubmed:issnType
Print
pubmed:volume
105
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21-8
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Cell alkalosis elevates cytosolic Ca2+ in rabbit resident alveolar macrophages.
pubmed:affiliation
Department of Internal Medicine, University of Texas Health Science Center, Houston, TX 77030, USA. thomas.heming@uth.tmc.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't