Linked Life Data

8240236

Source:http://linkedlifedata.com/resource/pubmed/id/8240236

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1993-12-3
pubmed:abstractText
We have previously shown that the hepoxilins are capable of increasing the intracellular free concentration of calcium ([Ca2+]i) in human neutrophils through a pertussis toxin-sensitive, extracellular calcium-independent pathway involving the mobilization of calcium from internal stores. A subsequent hepoxilin-induced and extracellular calcium-dependent influx of calcium is observed. In an effort to investigate further the role of these compounds in the human neutrophil, we investigated their potential effects on the action of known agonists such as formyl-methionine-leucine-phenylalanine (fMLP), platelet-activating factor (PAF) and leukotriene B4 (LTB4) on the mobilization of calcium. Hepoxilis dose-dependently inhibited the increases in [Ca2+]i induced by fMLP, PAF and LTB4. The hepoxilin concentration required for inhibition was around 100 ng/ml (3 x 10(-7) M). This concentration of hepoxilin did not cause any measurable change in [Ca2+]i. The extent of inhibition of the agonist-evoked rise in [Ca2+]i by hepoxilins was proportional to the increase in the calcium response evoked by hepoxilin beyond its threshold concentration. Additional experiments were carried out to investigate the mechanism for the hepoxilin effect. Using calcium-free medium and in the presence of sufficient amounts of thapsigargin (200 ng/ml) to maximally block the calcium pump (thereby achieving a constant rate of calcium leakage from stores), hepoxilin A3 increased further this rate of calcium leakage, indicating that hepoxilin acts by rapidly draining calcium from stores. Its potential (additional) thapsigargin-like action in blocking the pump, however, cannot be ruled out by these experiments. These observations suggest that the hepoxilins may serve an important negative regulatory function in the agonist-induced mobilization of calcium in these cells by depleting calcium stores.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-1320409, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-1400301, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-2001232, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-2106877, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-2171511, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-2177344, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-2787587, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-3140244, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-3748188, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-4179068, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-6087813, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-6250050, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-6406490, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-6429142, http://linkedlifedata.com/resource/pubmed/commentcorrection/8240236-7207461
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0264-6021
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
295 ( Pt 2)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
393-7
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Hepoxilin A3 inhibits the rise in free intracellular calcium evoked by formyl-methionyl-leucyl-phenylalanine, platelet-activating factor and leukotriene B4.
pubmed:affiliation
Research Institute, Hospital for Sick Children, Toronto, Canada.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't