Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1994-9-13
|
| pubmed:abstractText |
The Ca2+ responses of rat platelets are dominated by the influx of extracellular Ca2+ across the plasma membrane [Heemskerk, J. W. M., Feijge, M. A. H., Rietman, E. & Hornstra, G. (1991) FEBS Lett. 284, 223], which allows the study of Ca2+ entry into these cells by measuring increases in cytosolic Ca2+ concentration, [Ca2+]i. Several pieces of evidence indicated that, as in human platelets [Sage, S. O., Reast, R., & Rink, T. J. (1990) Biochem. J. 265, 675-680; Alonso, M., Alvarez, J., Montero, M., Sanchez, A. & García-Sancho, J. (1991) Biochem. J. 280, 783-789], agonist-stimulated Ca2+ entry was linked to the mobilisation of Ca2+ from intracellular stores: there was good correlation between the potency of receptor agonists in elevating [Ca2+]i in the presence or absence of external CaCl2; agonist-induced Ca2+ entry was inhibited to a similar degree as internal mobilisation by activators of cAMP-dependent or cGMP-dependent protein kinase or by the phospholipase C inhibitor, U73122; thapsigargin (an inhibitor of endomembrane Ca(2+)-ATPases) evoked store depletion and Ca2+ entry, which were both reduced by prior activation of cAMP-dependent or cGMP-dependent protein kinase but were not affected by U73122. In platelets with depleted Ca2+ stores, the addition of CaCl2 resulted in a considerable entry of Ca2+ which was insensitive to cAMP-dependent and cGMP-dependent protein kinase activation. In control platelets with full Ca2+ stores, CaCl2 potentiated the thrombin-induced generation of myo-inositol phosphates, suggesting that Ca2+ entry potentiated phospholipase C activity. Taken together, these results indicate that Ca2+ entry in rat platelets, (a) is mostly secondary to store depletion, (b) is not directly downregulated by cAMP-dependent and cGMP-dependent protein kinase, but indirectly by inhibition of store depletion, (c) can proceed in the absence of phospholipase C activation, but is stimulated by this activity probably by increased mobilisation of Ca2+ from the stores. These results lead to the concept that a major part of receptor-mediated Ca2+ entry in rat platelets is regulated in an indirect way by factors that stimulate or inhibit the degree of Ca2+ mobilisation from the internal stores.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/1-(6-((3-methoxyestra-1,3,5(10)-trie...,
http://linkedlifedata.com/resource/pubmed/chemical/15-Hydroxy-11 alpha,9...,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Chloride,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium-Transporting ATPases,
http://linkedlifedata.com/resource/pubmed/chemical/Cyclic AMP-Dependent Protein Kinases,
http://linkedlifedata.com/resource/pubmed/chemical/Cyclic GMP-Dependent Protein Kinases,
http://linkedlifedata.com/resource/pubmed/chemical/Egtazic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Estrenes,
http://linkedlifedata.com/resource/pubmed/chemical/Prostaglandin Endoperoxides...,
http://linkedlifedata.com/resource/pubmed/chemical/Pyrrolidinones,
http://linkedlifedata.com/resource/pubmed/chemical/Terpenes,
http://linkedlifedata.com/resource/pubmed/chemical/Thapsigargin,
http://linkedlifedata.com/resource/pubmed/chemical/Thrombin,
http://linkedlifedata.com/resource/pubmed/chemical/Thromboxane A2,
http://linkedlifedata.com/resource/pubmed/chemical/Type C Phospholipases
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0014-2956
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
15
|
| pubmed:volume |
223
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
543-51
|
| pubmed:dateRevised |
2010-11-18
|
| pubmed:meshHeading |
pubmed-meshheading:8055924-15-Hydroxy-11 alpha,9...,
pubmed-meshheading:8055924-Animals,
pubmed-meshheading:8055924-Blood Platelets,
pubmed-meshheading:8055924-Calcium,
pubmed-meshheading:8055924-Calcium Chloride,
pubmed-meshheading:8055924-Calcium-Transporting ATPases,
pubmed-meshheading:8055924-Cyclic AMP-Dependent Protein Kinases,
pubmed-meshheading:8055924-Cyclic GMP-Dependent Protein Kinases,
pubmed-meshheading:8055924-Drug Synergism,
pubmed-meshheading:8055924-Egtazic Acid,
pubmed-meshheading:8055924-Estrenes,
pubmed-meshheading:8055924-Male,
pubmed-meshheading:8055924-Platelet Activation,
pubmed-meshheading:8055924-Prostaglandin Endoperoxides, Synthetic,
pubmed-meshheading:8055924-Pyrrolidinones,
pubmed-meshheading:8055924-Rats,
pubmed-meshheading:8055924-Rats, Wistar,
pubmed-meshheading:8055924-Terpenes,
pubmed-meshheading:8055924-Thapsigargin,
pubmed-meshheading:8055924-Thrombin,
pubmed-meshheading:8055924-Thromboxane A2,
pubmed-meshheading:8055924-Type C Phospholipases
|
| pubmed:year |
1994
|
| pubmed:articleTitle |
Indirect regulation of Ca2+ entry by cAMP-dependent and cGMP-dependent protein kinases and phospholipase C in rat platelets.
|
| pubmed:affiliation |
Department of Human Biology, University of Limburg, Masstricht, The Netherlands.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|