Linked Life Data

2997148

Source:http://linkedlifedata.com/resource/pubmed/id/2997148

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
1985-11-29
pubmed:abstractText
We have observed previously that removal of extraplatelet Na+ blocks platelet secretion of dense granule contents in response to epinephrine, ADP, and 0.004 unit/ml thrombin, all agents which must mobilize arachidonic acid for its subsequent conversion to cyclooxygenase products in order to elicit platelet secretion. The present studies demonstrate that removal of extraplatelet Na+ blocks arachidonic acid mobilization in response to epinephrine, ADP, and 0.004 unit/ml thrombin without altering arachidonic acid conversion to thromboxane A2. The data also provide several lines of evidence which suggest that the blockade of arachidonic acid release due to removal of extraplatelet Na+ is a manifestation of blockade of Na+/H+ exchange system. 1) There is a concentration-dependent effect of extraplatelet Na+ (EC50 congruent to 55 mM) on [3H]arachidonic acid release such that mobilization is observed when [Na+]o greater than [Na+]i. 2) Increasing extraplatelet [H+] (i.e. decreasing extraplatelet pH from pH 7.35 to 6.8) causes a concentration-dependent decline in stimulus-provoked [3H]arachidonic acid release. 3) Ethylisopropylamiloride and other potent 5-amino analogs of amiloride block [3H]arachidonic acid release with a potency that parallels their effects on Na+/H+ exchange in other cellular systems. None of the above manipulations alter primary aggregation induced by epinephrine, ADP, or 0.004 unit/ml thrombin, indicating that stimulus-receptor binding, subsequent exposure of fibrinogen receptors, and fibrinogen-mediated platelet-platelet cross-linking are not significantly inhibited by [3H]arachidonic acid release in response to greater than 0.1 unit/ml thrombin, a stimulus that can elicit platelet secretion in the absence of products of the cyclooxygenase pathway. Therefore, Na+/H+ exchange may selectively modulate arachidonic acid mobilization in response to the so-called "weak agonists," agonists that require this mobilization to effect vigorous platelet aggregation and dense granule secretion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Diphosphate, http://linkedlifedata.com/resource/pubmed/chemical/Amiloride, http://linkedlifedata.com/resource/pubmed/chemical/Arachidonic Acid, http://linkedlifedata.com/resource/pubmed/chemical/Arachidonic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Epinephrine, http://linkedlifedata.com/resource/pubmed/chemical/Serotonin, http://linkedlifedata.com/resource/pubmed/chemical/Sodium, http://linkedlifedata.com/resource/pubmed/chemical/Sodium-Hydrogen Antiporter, http://linkedlifedata.com/resource/pubmed/chemical/Thrombin, http://linkedlifedata.com/resource/pubmed/chemical/Thromboxanes, http://linkedlifedata.com/resource/pubmed/chemical/ethylisopropylamiloride
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
260
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12910-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Inhibitors of Na+/H+ exchange block stimulus-provoked arachidonic acid release in human platelets. Selective effects on platelet activation by epinephrine, ADP, and lower concentrations of thrombin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't