Shape and cytoplasmic filaments in control and lidocaine-treated human platelets.
Shape and cytoplasmic filaments in control and lidocaine-treated human platelets.
复制标题
对照和利多卡因处理的人血小板的形状和细胞质丝。
作者：
V. Nachmias;J. Sullender;A. Asch
为了检查血小板的内部结构，我们使用了负染色技术后，快速裂解的凝胶过滤的血小板在电子显微镜网格。通过制备程序活化的血小板在细胞体中含有细（7-8 nm）细丝的内部网络，在微刺中与平行细丝连续。纤维结合HMM-S1形成箭头结构。在微刺中的细丝的紧密束具有惊人的轴向周期性类似于在含有肌肉调节蛋白的肌动蛋白类晶体中看到的周期性。几乎完整的微管环有时存在于或邻近于具有形成的微刺的裂解细胞;它们表现为连续的环。利多卡因（30 mM）可逆地抑制和逆转70%或更多的血小板群体中的微粒形成，即使在腺苷二磷酸添加。处理的血小板呈球形，而不是盘状，缺乏细丝网络和微管，含有无定形或颗粒状的内部细胞质。束厚0.3毫米长的细丝，类似于肌球蛋白聚集体，形成在体外从纯化的血小板肌球蛋白只看到。在处理的储存细胞中，而不是在对照中。我们的结论是，利多卡因抑制微刺与细丝束的解体，重组的微刺涉及重新组装成束的细丝，微管是不是一个强制性的一部分微刺。
In order to examine the internal structure of platelets we used a negative stain technique following rapid lysis of gel-filtered platelets on electron microscope grids. Platelets activated by the preparative procedure contained an internal network of thin (7-8 nm) filaments in the body of the cells, continuous with parallel filaments in the microspikes. The filaments bound HMM-S1 to form arrowhead structures. The tight bundles of thin filaments in the microspikes possessed a striking axial periodicity similar to the periodicity seen in actin paracrystals containing muscle regulatory proteins. Nearly complete microtubule circlets were sometimes present in or adjacent to lysing cells with formed microspikes; they appeared as continuous loops. Lidocaine (30 mM) reversibly suppressed and reversed microspike formation in 70% or more of platelet populations even after adenosine diphosphate addition. Treated platelets were spherical, not discoid, lacked the thin-filament network and microtubules and contained an amorphous or granular internal cytoplasm. Bundles of thick 0.3-Mm long filaments, similar to myosin aggregates, formed in vitro from purified platelet myosin were seen only. in treated stored cells, and not in controls. We conclude that lidocaine suppression of microspikes is correlated with disassembly of thin-filament bundles, that reformation of microspikes involves reassembly of filaments into bundles, and that microtubules are not an obligatory part of microspikes.