White J G, Estensen R D
Am J Pathol. 1974 Mar;74(3):453-66.
Phorbol myristate acetate (PMA), the active principle of croton oil, is a potent platelet aggregating agent. A previous electron microscopic study indicated that PMA caused selective labilization of platelet granules. The present investigation has employed cytochemical procedures to clarify problems concerning the action of PMA on platelets. Results of this study confirm the suggestion that vacuoles in PMA-treated platelets derive primarily from granules, and demonstrate that the swollen vacuoles are continuous with channels of the open canalicular system (OCS) and surrounding plasma. Despite loss of the barrier separating vacuolated granules from the OCS, the contents of the organelles were not extruded from the PMA aggregated platelets. Stabilization of platelet surface membranes did not inhibit the action of PMA on platelet granules, and examination of replicas of freeze-fractured PMA platelets failed to reveal any specific injury produced by the agent. The findings have elucidated some of the effects of PMA on platelet structure, but have not solved the basic mechanism of drug action.
佛波醇肉豆蔻酸酯乙酸酯（PMA）是巴豆油的活性成分，是一种强效的血小板聚集剂。先前的电子显微镜研究表明，PMA会导致血小板颗粒选择性不稳定。本研究采用细胞化学方法来阐明有关PMA对血小板作用的问题。这项研究的结果证实了以下观点：经PMA处理的血小板中的空泡主要来源于颗粒，并表明肿胀的空泡与开放小管系统（OCS）的通道和周围血浆相连。尽管分隔空泡化颗粒与OCS的屏障消失，但细胞器的内容物并未从PMA聚集的血小板中挤出。血小板表面膜的稳定化并未抑制PMA对血小板颗粒的作用，对冷冻断裂的PMA血小板复制品的检查未能发现该试剂产生的任何特异性损伤。这些发现阐明了PMA对血小板结构的一些影响，但尚未解决药物作用的基本机制。
