Activation of rabbit platelet phospholipase and thromboxane synthesis by 1-o-hexadecyl/octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (platelet activating factor)
| Autor: | Donald J. Hanahan, Susan J. Klusick, J. O. Shaw |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Blood Platelets
Serotonin medicine.medical_specialty Thromboxane Biophysics Arachidonic Acids Phospholipase Biochemistry Serotonin secretion Glycerides chemistry.chemical_compound Endocrinology Internal medicine medicine Animals Platelet Platelet Activating Factor Phospholipids Dose-Response Relationship Drug Platelet-activating factor Lysophosphatidylcholines Thromboxanes Phosphatidic acid Thromboxane B2 Kinetics chemistry Phospholipases Arachidonic acid Rabbits |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism. 663:222-229 |
| ISSN: | 0005-2760 |
| DOI: | 10.1016/0005-2760(81)90208-3 |
| Popis: | 1-O-Hexadecyl/octadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (AGEPC), structurally identical with platelet activating factor, is a potent stimulus for rabbit platelet aggregation and serotonin secretion. AGEPC at concentrations between 10(-10) and 10(-8) M induced stimulation of rabbit platelet synthesis of thromboxane B2. The dose vs. response curve for platelet thromboxane B2 synthesis was displaced slightly towards higher stimulus concentrations compared to [3H]serotonin secretion, with half-maximal concentrations of 2.5 . 10(-9) and 8 . 10(-10) M, respectively. Rates of thromboxane B2 synthesis and secretion were similar with a t 1/2 max of 4.0-4.5 s for both processes. AGEPC induced a decrease in platelet [14C]arachidonic acid in both phosphatidylinositol and phosphatidylcholine, although [14C]arachidonic acid turnover in phosphatidylcholine was not observed below 1 . 10(-8) M AGEPC. Concomitantly, this decrease in phospholipid [14C]arachidonic acid was associated with a marked increase of radiolabel in platelet diacylglycerol and phosphatidic acid 15 s after AGEPC addition, suggesting the possibility of a phospholipase C-diacylglycerol lipase mechanism of fatty acid cleavage. As observed previously with secretion and aggregation, removal of the 2-acetyl group from AGEPC abrogated all capacity of this molecule to stimulate platelet phospholipase. This study indicates that AGEPC (or platelet activating factor) activation of rabbit platelet phospholipase occurs in a time-course and concentration range similar to that required for [3H]serotonin secretion. |
| Databáze: | OpenAIRE |
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