Effects of extracellular Ca2+ and the intracellular Ca2+ antagonist 8-(N,N-diethylamino) octyl-3,4,5-trimethoxybenzoate on rabbit platelet conversion of arachidonic acid into thromboxane
| Autor: | J. O. Shaw |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
Blood Platelets
Intracellular Fluid Arachidonic Acid Thromboxane Thromboxanes Rabbit (nuclear engineering) Arachidonic Acids Biology Biochemistry Thromboxane B2 chemistry.chemical_compound Endocrinology chemistry Gallic Acid Ca2 antagonist Extracellular Animals Calcium Arachidonic acid Platelet Rabbits Extracellular Space Intracellular |
| Zdroj: | Prostaglandins. 21:571-579 |
| ISSN: | 0090-6980 |
| DOI: | 10.1016/0090-6980(81)90005-8 |
| Popis: | The regulatory role of Ca2+ on the conversion of arachidonic acid (AA) into thromboxane B2 (TXB2) was examined in washed rabbit platelets, whose secretory processes are known to have requirements for extracellular Ca2+. Varying the extracellular free Ca2+ [Caf2+] concentration from less than 10(-8) M to 10(-3) M had no significant effect on the synthesis of immunoreactive TXB2 by rabbit platelets incubated with 1-4 microM AA. On the other hand, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), a putative antagonist of intracellular Ca2+ movement, inhibited AA-stimulated synthesis of TXB2 in a concentration dependent manner--an effect which could be partially overcome by increasing the AA concentration. The TMB-8 inhibition could not be reversed by increasing the [Ca2+f]. Studies examining platelet metabolism of 14C-AA and 14C-prostaglandin H2 demonstrated that TMB-8 inhibited platelet cyclooxygenase, but not thromboxane synthetase. These studies demonstrate the absence of a requirement for [Ca2+f] but suggest the presence of a TMB-8 sensitive intracellular Ca2+ pool in the rabbit platelet synthesis of TXB2 from AA. |
| Databáze: | OpenAIRE |
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