Nüesch H, Stocker R F
Cell Tissue Res. 1975 Dec 10;164(3):331-55. doi: 10.1007/BF00223013.
In the moth Antheraea polyphemed at the onset of adult development. The subsequent breakdown of the isolated motor stulongated vesicles similar in structure to channels of smooth ER, appear in large numbers in the axoplasm. Their nature as well as the functional aspects of early axonal changes are discussed. From the 7th day onward two types of axonal breakdown become prominent. The first is characterized 0y swelling axon profiles, distorted vesicles and strongly shrunken mitochondria, uhile shrinking axon profiles containing tightly packed mitochondria and unaltered vesicles are typical of the second. Both types presumably take place independently of each other in different axon terminals. Axons and the contents of at least the first type are finally removed by transformation into lamellar bodies. Glial processes obviously behave independently of degenerating terminals; they loose any contact with them and never act as phagocytes for axon remnants. During the whole period of breakdown undifferentiated contacts between nerve fibers and muscle anlagen are present but synaptic structures as in normal developing dlm have never been observed. This fact, in comparison with earlier studies, suggests a lack of trophic nervous activity on the muscle anlagen tissue. A short time after removal of the isolated stumps new nerve tracts appear between dlm-fibers (which are, of course, strongly retarded in development). They are presumably sensory wing nerves which lack a guide structure to the central target, due to axotomy. Neuromuscular contacts or even junctions formed by axons of these nerves have occasionally been detected on the dlm. Their nature is discussed. Wallerian axon degeneration is compared to the normal, metamorphic breakdown of the innervation of the larval dlm-precursor. In contrast to the former, glial processes here remain in contact with the terminals. Glia and axons first swell. Then most glial processes are transformed into lamellar bodies whereas neurites shrink and become electron-dense. Axonal organelles remain intact for a long period.
在多音柞蚕蛾成虫发育开始时。随后分离出的运动神经元发生解体，出现大量结构类似于滑面内质网通道的拉长囊泡，存在于轴浆中。讨论了它们的性质以及早期轴突变化的功能方面。从第7天起，两种类型的轴突解体变得明显。第一种表现为轴突轮廓肿胀、囊泡变形和线粒体强烈收缩，而第二种则以含有紧密堆积线粒体和未改变囊泡的收缩轴突轮廓为典型特征。这两种类型可能在不同的轴突终末相互独立地发生。轴突以及至少第一种类型的内容物最终通过转化为板层小体而被清除。神经胶质突起显然与退化的终末独立行动；它们与终末失去任何接触，从不作为轴突残余物的吞噬细胞。在整个解体期间，神经纤维与肌肉原基之间存在未分化的接触，但从未观察到正常发育的双翅目幼虫中那样的突触结构。与早期研究相比，这一事实表明肌肉原基组织缺乏营养性神经活动。切除分离的残端后不久，在双翅目幼虫纤维（其发育当然严重滞后）之间出现了新的神经束。它们可能是感觉翅神经，由于轴突切断，缺乏通向中枢靶标的引导结构。这些神经的轴突偶尔在双翅目幼虫上检测到神经肌肉接触甚至连接。讨论了它们的性质。将瓦勒氏轴突退化与幼虫双翅目幼虫前体神经支配的正常变态解体进行了比较。与前者不同，这里的神经胶质突起与终末保持接触。神经胶质和轴突首先肿胀。然后大多数神经胶质突起转化为板层小体，而神经突收缩并变得电子致密。轴突细胞器在很长一段时间内保持完整。
