Owen N E, Le Breton G C
Am J Physiol. 1981 Oct;241(4):H613-9. doi: 10.1152/ajpheart.1981.241.4.H613.
Binding of intracellular Ca2+ was measured in intact human blood platelets using the fluorescent Ca2+ probe, chlortetracycline, and a photon-counting microspectrofluorometer. Low doses of epinephrine, A23187, or prostaglandin endoperoxide analog U46619 induced a release of intraplatelet membrane-bound Ca2+. When platelet transmembrane Ca2+ flux was blocked by verapamil or ethylenediaminetetraacetic acid (EDTA), Ca2+ mobilization in response to epinephrine was inhibited, whereas A23187- or U46619-induced Ca2+ release was unchanged. When indomethacin was used to inhibit cyclo-oxygenase activity, Ca2+ mobilization in response to epinephrine or U46619 was partially blocked, whereas Ca2+ release in response to A23187 was unaltered. The relationship between platelet cyclic adenosine 3',5'-monophosphate (cAMP) and intraplatelet Ca2+ binding was also investigated. Prostaglandin E1 or prostacyclin was found to markedly elevate cAMP as well as enhance platelet Ca2+ binding. These effects were augmented by inhibition of phosphodiesterase activity using RO201724. The relationship between cAMP and Ca2+ binding was linear in the range of 10-60 pmoles cAmP/ml platelet-rich plasma. In addition the increase in cAMP stimulated by prostaglandin E1 or prostacyclin reduced the ability of epinephrine, A23187, or U46619 to induce intraplatelet Ca2+ mobilization.
使用荧光钙探针氯四环素和光子计数显微分光荧光计，在完整的人血小板中测量细胞内钙离子的结合情况。低剂量的肾上腺素、A23187或前列腺素内过氧化物类似物U46619可诱导血小板内与膜结合的钙离子释放。当血小板跨膜钙通量被维拉帕米或乙二胺四乙酸（EDTA）阻断时，肾上腺素诱导的钙离子动员受到抑制，而A23187或U46619诱导的钙离子释放未改变。当使用吲哚美辛抑制环氧化酶活性时，肾上腺素或U46619诱导的钙离子动员被部分阻断，而A23187诱导的钙离子释放未改变。还研究了血小板环磷酸腺苷（cAMP）与血小板内钙离子结合之间的关系。发现前列腺素E1或前列环素可显著升高cAMP，并增强血小板钙离子结合。使用RO201724抑制磷酸二酯酶活性可增强这些作用。在10 - 60皮摩尔cAMP/毫升富血小板血浆范围内，cAMP与钙离子结合之间的关系呈线性。此外，前列腺素E1或前列环素刺激引起的cAMP增加降低了肾上腺素、A23187或U46619诱导血小板内钙离子动员的能力。
