White J G, Clawson C C
Diagn Histopathol. 1982 Jan-Mar;5(1):3-10.
Recent investigations have suggested that channels of the surface connected open canalicular system are the major source of membrane contributing to increased surface area of platelets following activation or uptake of particulates. However, study of large latex particle phagocytosis suggested that channels filled with spherules become dilated and lose connections with the outer surface, but do not become extruded onto the platelet membrane. The present study has employed electron dense tracers, freeze-fracture and transmission electron microscopy to follow the uptake of small latex spherules by blood platelets. Small particles were rapidly incorporated into the numerous channels without causing significant changes in surface or internal morphology. Intramembranous particles on both E and P faces in replicas of freeze-fractured platelets were unaffected by ingestion of latex spherules. Prolonged exposure to small latex particles caused platelets to lose their discoid form. The irregular spheres contained two or three dilated vacuoles filled with latex and a reduced number of single channels. Results of this and previous studies suggest that channels of the open canalicular system are internalized in platelets after phagocytosis, and are not extruded onto the platelet surface.
最近的研究表明，表面连接的开放小管系统的通道是血小板在激活或摄取颗粒后导致表面积增加的膜的主要来源。然而，对大乳胶颗粒吞噬作用的研究表明，充满小球体的通道会扩张并与外表面失去连接，但不会被挤出到血小板膜上。本研究采用电子致密示踪剂、冷冻断裂和透射电子显微镜来追踪血小板对小乳胶球体的摄取。小颗粒迅速被纳入众多通道，而不会引起表面或内部形态的显著变化。冷冻断裂血小板复制品中E面和P面上的膜内颗粒不受乳胶球体摄取的影响。长时间暴露于小乳胶颗粒会使血小板失去盘状形态。不规则球体包含两到三个充满乳胶的扩张液泡和数量减少的单通道。本研究及先前研究的结果表明，开放小管系统的通道在吞噬作用后会内化于血小板中，而不会被挤出到血小板表面。
