Requirement for different Ca2+ pools in the activation of rabbit plateletsII. Phospholipase activity
| Autor: | J. O. Shaw, Roger M. Lyons |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
Blood Platelets
Platelet Aggregation Thromboxane Biophysics Arachidonic Acids Phospholipase Biochemistry chemistry.chemical_compound Thrombin Gallic Acid medicine Extracellular Animals Platelet Phosphatidylinositol Molecular Biology Arachidonic Acid Platelet-activating factor Thromboxane B2 EGTA chemistry Phospholipases Calcium Rabbits medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - General Subjects. 714:500-504 |
| ISSN: | 0304-4165 |
| DOI: | 10.1016/0304-4165(82)90160-x |
| Popis: | The effects of extracellular Ca2+ concentration and the putative antagonist of intracellular Ca2+ movement, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) on platelet phospholipase activity and thromboxane B2 synthesis were examined in rabbit platelets stimulated by platelet activating factor, thrombin and ionophore A23187. TMB-8 markedly inhibited the platelets stimulated by platelet activating factor, thrombin and ionophore A23187. TMB-8 markedly inhibited the platelet activating factor-induced decrease in [14C]arachidonate content in platelet phosphatidylcholine and phosphatidylinositol, while showing minimal effects on thrombin-induced phospholipase activation. A23187 stimulation of these processes was inhibited to an intermediate degree by TMB-8. In contrast, extracellular Ca2+ removal inhibited phospholipase activity to a similar degree with all three stimuli. Moreover, the threshold concentration of extracellular Ca2+ for phospholipase activation, as measured by thromboxane B2 synthesis, was similar for platelet activating factor- and thrombin-stimulated platelets. These data provide evidence that, while platelet activating factor and thrombin may, to some extent, have similar requirements for extracellular Ca2+, they utilize a TMB-8 sensitive step to different degrees during activation of platelet phospholipase. |
| Databáze: | OpenAIRE |
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