Linked Life Data

1849943

Source:http://linkedlifedata.com/resource/pubmed/id/1849943

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1991-5-23
pubmed:abstractText
For superoxide (O2-) responses of human neutrophils stimulated by FMLP, experiments were designed to assess the requirement of extracellular calcium [( Ca2+]o) for priming of O2- responses by platelet-activating factor (PAF), PMA, or ionomycin. Although priming by PMA did not require [Ca2+]o, there was, as expected, a requirement for [Ca2+]o for the optimal priming effects of PAF and ionomycin. The ED50 value for [Ca2+]o in the priming function of PAF was 105 microM. The [Ca2+]o-dependent priming with ionomycin was bimodal with two ED50 values for [Ca2+]o of 90 microM and 3.2 mM. Optimal priming by PAF required at least 4-min exposure of cells to [Ca2+]o. Cells primed by PAF exhibited faster initial rates of O2-production after addition of FMLP, but the duration of O2- production was not prolonged. Whereas PAF-primed responses to FMLP are usually associated with increases in intracellular calcium [( Ca2+]i) after addition of FMLP, two conditions were found in which O2- responses to FMLP in PAF-primed cells occurred in the absence of any detectable increase in [Ca2+]i. When cells were loaded with the calcium chelator, bis-(O-aminophenoxy)-ethane-H,N,N',N'-tetraacetic acid, and then primed with PAF, normal amounts of inositol 1,4,5-trisphosphate were formed, but no increase in [Ca2+]i occurred after addition of FMLP even though the cells exhibited a fully primed O2- response; in Ca2(+)-depleted and ionomycin-permeabilized cells that were primed with PAF and then stimulated with FMLP, O2- was generated in amounts comparable to reference control (primed) cells, but there was suppressed production of inositol 1,4,5-trisphosphate and no increase in [Ca2+]i after addition of FMLP to PAF-primed cells. These data confirm the requirement of [Ca2+]o for optimal priming of neutrophils by PAF and ionomycin (but not cells primed by PMA) and indicate that, under certain conditions, generation of O2- in response to FMLP in PAF-primed neutrophils can occur independent of any increase in [Ca2+]i.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
146
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3124-31
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Superoxide responses to formyl-methionyl-leucyl-phenylalanine in primed neutrophils. Role of intracellular and extracellular calcium.
pubmed:affiliation
Department of Pathology, University of Michigan Medical School, Ann Arbor 48109.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.