Pulido-Caballero J, Jiménez-Sampedro F, Echevarría-Aza D, Martínez-Millán L
Instituto de Neurociencias F. Olóriz, University of Granada, Spain.
Neuroscience. 1994 Apr;59(3):765-73. doi: 10.1016/0306-4522(94)90193-7.
Strings of vimentin-positive rosary-bead-like formations in the rabbit superior colliculus were studied. The size and distance between beads varied from one string to another, and within a given string. The formations were similar in number and distribution in the two superior colliculi. Successions of beads were found mainly in the medial and deep layers, and represented not more than 1% of the radial glial fibers. The strings were in continuity at deep levels with segments of varicose fibers of radial glia, which in turn were continuous with fibers of normal appearance. These observations suggest a temporal sequence of evolution, starting with the normal radial glial fiber, which acquires swellings that in turn give rise to discrete beads; in subsequent stages, the beads become smaller and more widely separated. In the newborn rabbit, these formations are seen mainly in laterobasal regions of the superior colliculus, and spread throughout the colliculus by the end of week one of postnatal life, becoming more numerous in medial regions. We suggest that these formations represent a mechanism of removal of at least part of the radial glial fibers, and discuss the possible relation between these formations and the transformation of radial glia into astrocytes.
对兔上丘中波形蛋白阳性的念珠状结构进行了研究。念珠的大小和间距在不同的串之间以及同一串内均有所不同。这两个上丘中的结构在数量和分布上相似。念珠序列主要见于内侧层和深层，占放射状胶质纤维的比例不超过1%。这些串在深层与放射状胶质曲张纤维段相连，而这些曲张纤维段又与外观正常的纤维相连。这些观察结果提示了一个时间上的演化顺序，始于正常的放射状胶质纤维，其出现肿胀，进而形成离散的念珠；在随后的阶段，念珠变得更小且间距更大。在新生兔中，这些结构主要见于上丘的外侧基部区域，在出生后第一周末遍布整个上丘，在内侧区域数量增多。我们认为这些结构代表了至少部分放射状胶质纤维的清除机制，并讨论了这些结构与放射状胶质向星形胶质细胞转化之间的可能关系。
