Quantal Release of Serotonin from Platelets
Quantal Release of Serotonin from Platelets
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DOI：
10.1021/ac8024202
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发表时间：
2009-04-15
影响因子：
7.4
通讯作者：
Haynes, Christy L.
中科院分区：
文献类型：
--
作者：
Ge, Shencheng;White, James G.;Haynes, Christy L.
尽管已知血小板在止血中起关键作用，部分通过其摄取、储存和释放5-羟色胺来介导，但该过程仍有许多未探索的方面。本文采用单细胞安培法来表征血小板致密体颗粒中5-羟色胺的动态分泌。三维随机游走模拟的基础上，估计检测效率与碳纤维微电极和血小板之间的不同间距，很明显，检测到的电荷可能代表完全氧化的释放颗粒内容物，因此，是一个很好的方法来计算每个颗粒中的血清素浓度。使用基于透射电子显微镜（TEM）数据的测量电荷和体积估计值，5-羟色胺的颗粒浓度约为0.5 M。模拟的尖峰宽度显着窄于大多数测得的电流尖峰，清楚地表明，存储的血清素是高度相关的聚集体，而不是自由扩散的致密体颗粒。此外，通过改变细胞外缓冲液的温度和pH值，以调节从致密体颗粒向细胞外空间递送5-羟色胺的驱动力，很明显，尽管血小板化学信使的储存和分泌与其他分泌细胞相似，但仍存在一些重要的区别。
Even though platelets are known to play a critical role in hemostasis, mediated in part by their uptake, storage, and release of serotonin, there are many unexplored aspects of this process. Herein, single-cell amperometry is employed to characterize the dynamic secretion of serotonin from platelet dense-body granules. On the basis of a three-dimensional random walk simulation that estimates detection efficiency with varied spacing between the carbon-fiber microelectrode and the platelet, it is clear that the detected charge likely represents complete oxidation of the released granule contents and, thus, is a good method to calculate the serotonin concentration in each granule. Using the measured charge and volume estimates based on transmission electron microscopy (TEM) data, the granular concentration of serotonin is approximately 0.5 M. The simulated spike widths are significantly narrower than most of the measured amperometric spikes, clearly indicating that the stored serotonin is highly associated with an aggregate rather than freely diffusible within the dense-body granule. Additionally, by varying extracellular buffer temperature and pH to adjust the driving forces for serotonin delivery from the dense-body granules to the extracellular space, it is clear that, although platelet chemical messenger storage and secretion is similar to that of other secretory cells, there are some important distinctions.