INJURY-INDUCED VESICULATION AND MEMBRANE REDISTRIBUTION IN SQUID GIANT-AXON
INJURY-INDUCED VESICULATION AND MEMBRANE REDISTRIBUTION IN SQUID GIANT-AXON
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DOI：
10.1016/0005-2736(90)90135-b
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发表时间：
1990-04-30
期刊：
影响因子：
--
通讯作者：
STEIN, PG
中科院分区：
文献类型：
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作者：
FISHMAN, HM;TEWARI, KP;STEIN, PG
在海水中，通过切割或拉伸损伤鱿鱼的巨大轴突，可启动下列未见报道的过程：(1)在距损伤部位轴突几毫米处的腋下区域形成小泡，随后(2)小泡融合，形成大的小泡(直径20-50微米)，形成“轴小体”，最后(3)轴体向损伤部位迁移并聚集。有些轴小体从切端长出，直径可达250微米。轴突损伤后，除非外液中存在二价阳离子(10 MM)，否则不会形成轴突。对钙离子的需求和其他离子的作用类似于切断的鱿鱼轴突的细胞骨架收缩(Gallant，P.E.(1988)J.Neurosci)。8,1479-1484)和蟑螂横断轴突电封闭(Yawo，H.和Kuro，M.(1985)J.Neurosci)。5、1626-1632)。轴小体可能由来自不同来源(如轴膜、细胞器和雪旺细胞)的膜组成；然而，轴体形成定位于轴膜内区以及对二价阳离子的形成依赖表明主要参与内质网池的形成。从横断轴突的切断端自发释放的轴小体切除斑块的膜片钳显示12-pS K+通道，并提示其他通道类型。损伤诱导的囊泡形成和膜的重新分布似乎是轴突变性或修复和再生之前的短期(几分钟到几小时)的基本过程。中轴体的形成为研究离子通道和其他细胞器的膜过程提供了膜制剂。
Injury of isolated squid giant axons in sea water by cutting or stretching initiates the following unreported processes: (i) vesiculation in the subaxolemmal region extending along the axon several mm from the site of injury, followed by (ii) vesicular fusions that results in the formation of large vesicles (20-50 .mu.m diameter), ''axosomes'', and finally (iii) axosomal migration to and accumulation at the injury site. Some axosomes emerge from a cut end, attaining sizes up to 250 .mu.m in diameter. Axosomes did not form after axonal injury unless divalent cations (Ca2+ or Mg2+) were present (10 mM) in the external solution. The requirement for Ca2+ and the action of other ions are similar to that for cut-end cytoskeletal constriction in transected squid axons (Gallant, P.E. (1988) J. Neurosci. 8, 1479-1484) and for electrical sealing in transected axons of the cockroach (Yawo, H. and Kuno, M. (1985) J. Neurosci. 5, 1626-1632). Axosomes probably consist of membrane from different sources (e.g., axolemma, organelles and Schwann cells); however, localization of axosomal formation to the inner region of the axolemma and the formation dependence on divalent cations suggest prinicipal involvement of cisternae of endoplasmic reticulum. Patch clamp of excised patches from axosomes liberated spontaneously from cut ends of transected axons showed a 12-pS K+ channel and gave indications of other channel types. Injury-induced vesiculation and membrane redistribution seem to be fundamental processes in the short-term (minutes to hours) that precede axonal degeneration or repair and regeneration. Axosomal formation provides a membrane preparations for the study of ion channels and other membrane process from inaccessible organelles.