Rendu F, Brohard-Bohn B
U428 INSERM, Faculté de Pharmacie, 4 Avenue de l'Observatoire, 75006-Paris, France.
Platelets. 2001 Aug;12(5):261-73. doi: 10.1080/09537100120068170.
Although anucleated, blood platelets are highly organized cells rich in different types of organelles. Three specific granule populations store different types of constituents, some of which are at high concentrations. Platelets thus transport some specific compounds through the whole body. During circulation, platelets are reactive to various stimuli and release the materials stored in the specific granules. This 'release reaction' is an important step of primary haemostasis. Energy and messengers required for platelet reactivity are provided by mitochondria and the dense tubular system. Each granule population has specific properties concerning both the structure and the role played by the released constituents. Dense granules contain small non-protein molecules that are secreted to recruit other platelets. alpha-Granules contain large adhesive and healing proteins. Lysosomes contain hydrolases able to eliminate the circulating platelet aggregate. The extrusion of storage granules' content to the platelet's environment occurs according to regulated secretion events: movements of granules, apposition and fusion of granule and plasma membranes. Typical platelet disorders resulting from a storage granule abnormality are referred to as a storage pool defect and are characterized by a prolonged bleeding time.
尽管无细胞核，但血小板是高度有组织的细胞，富含不同类型的细胞器。三种特定的颗粒群体储存不同类型的成分，其中一些成分浓度很高。血小板因此将一些特定化合物输送到全身。在循环过程中，血小板对各种刺激有反应，并释放储存在特定颗粒中的物质。这种“释放反应”是初级止血的重要步骤。血小板反应所需的能量和信使由线粒体和致密管状系统提供。每个颗粒群体在结构和所释放成分的作用方面都有特定的特性。致密颗粒含有小的非蛋白质分子，这些分子被分泌出来以招募其他血小板。α颗粒含有大型粘附和愈合蛋白。溶酶体含有能够消除循环中的血小板聚集体的水解酶。储存颗粒内容物向血小板周围环境的挤出是根据调节性分泌事件发生的：颗粒的移动、颗粒与质膜的并置和融合。由储存颗粒异常导致的典型血小板疾病被称为储存池缺陷，其特征是出血时间延长。
