ENDOCYTOSIS AND AUTOPHAGY IN DYING NEURONS - AN ULTRASTRUCTURAL-STUDY IN CHICK-EMBRYOS
ENDOCYTOSIS AND AUTOPHAGY IN DYING NEURONS - AN ULTRASTRUCTURAL-STUDY IN CHICK-EMBRYOS
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DOI：
10.1002/cne.902830310
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发表时间：
1989-05-15
影响因子：
2.5
通讯作者：
CLARKE, PGH
中科院分区：
文献类型：
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作者：
HORNUNG, JP;KOPPEL, H;CLARKE, PGH
为了了解发育中的峡部视核中自然发生的神经元死亡，我们强调了其最可能的原因之一，未能从视网膜轴突终末区获得足够的营养维持，并对垂死的神经元进行了超结构研究。通过眼内注射秋水仙碱阻断了逆行营养维持，秋水仙碱导致所有峡部视神经元死亡，这是正常发育过程中发生的两种或多种细胞死亡中的一种。本文论述了这种细胞死亡的非常突出的细胞质方面，特别是外源辣根过氧化物酶和自噬的吸收。还存在核变化，其主要在随附的论文中论述（Clarke和Hornung，J. Comp. Neurol. 283：438-449，“89）。在索马和树突中均出现大量的胞质空泡，它们主要有三种，其中最小的（直径小于0.5 μ m）和非结构化的内容物，而较大的两种（1-2 μ m和2-7 μ m）是次级溶酶体（主要是残留体）。血管内注射辣根过氧化物酶标记的所有三种液泡，但不是游离的细胞质，表明摄取是通过内吞作用，而不是通过膜上的孔泄漏，我们未能检测到任何这样的孔证实。我们猜想，最小的空泡是初级内体，这些内体随后与中间类型的空泡融合，最大的空泡是由这些中间类型的空泡融合形成的。内吞作用的目的可能是将质膜逐段引导到溶酶体中进行破坏。
In an effort to understand naturally occurring neuronal death in the developing isthmo-optic nucleus, we have accentuated one of its most probably causes, failure to receive adequate trophic maintenance from the axonal terminal zone in the retina, and have studied the dying neurons ultrasructurally. Retrograde trophic maintenance was blocked by means of intraocularly injected colchicine, which caused all the isthmo-optic neurons to die by just one of the two or more kinds of cell death that they undergo during normal development. The present paper deals with the very prominent cytoplasmic aspects of this kind of cell death, notably the uptake of exogenous horseradish peroxidase and autophagy. There were also nuclear changes, which are dealt with mainly in the accompanying paper (Clarke and Hornung, J. Comp. Neurol. 283:438-449, ''89). Numerous cytoplasmic vacuoles occurred in both soma and dendrites, and they were of three main kinds, of which the smallest (less than 0.5 .mu.m diameter) and unstructured contents, whereas the larger two (1-2 .mu.m and 2-7 .mu.m)were secondary lysosomes (mostly residual bodies). Intravascularly injected horseradish peroxidase labeled all three kind of vacuole but not the free cytoplasm, indicating that the uptake was by endocytosis rather than leakage through holes in the membrane, as is confirmed by our failure to detect any such holes. We suspect that the smallest vacuoles are the primary endosomes, that these subsequently fuse with vacuoles of the intermediate kind, and that the largest vacuoles are formed by the fusion of these latter. The purpose of the endocytosis may be to channel the plasma membrane piecemeal into the lysosomes for destruction.