Roberts M H, Bernstein M F, Moore R Y
Brain Res. 1987 Mar;429(1):59-66. doi: 10.1016/0165-3806(87)90138-6.
The capacity of the rat anterior hypothalamus, and particularly the suprachiasmatic nucleus (SCN), to develop and differentiate when removed from its normal environment was examined in this study using light and electron microscopy. The hypothalamus from fetuses ranging in age from embryonic day 12 (E 12) to E 16 was transplanted to the anterior chamber of the eye of adult rats. In initial experiments, we found that transplants from E 15 fetuses and older routinely differentiated into fields of neurons with extensive neuropil with an appearance similar to the anterior hypothalamic area. Groups of small, compactly organized neurons were observed only occasionally in this tissue. Ultrastructural analysis of these transplants typically revealed well-differentiated neuronal perikarya and neuropil with a complex synaptic organization similar in appearance to the normal rat anterior hypothalamic area. Occasionally both mature and immature tissue coexisted in some of the transplants. Tissue from young embryos (E 12-14) frequently showed development of a compact, small neuron nucleus with the cytoarchitectonic appearance of the SCN. At least 45 days were required after transplantation for the successful differentiation to occur in this situation. The SCN in these transplants displayed vasoactive intestinal polypeptide-immunoreactive cells and fibers surrounded by vasopressin-immunoreactive cells and fibers, similar to the pattern observed in the normal adult SCN. Our results indicate that the anterior hypothalamus will differentiate normally in oculo and that the phenotypic specification of the SCN occurs prior to the birthdate of its component neurons.
在本研究中，使用光学显微镜和电子显微镜检查了大鼠前下丘脑，特别是视交叉上核（SCN）在脱离其正常环境时发育和分化的能力。将年龄从胚胎第12天（E12）到E16的胎儿下丘脑移植到成年大鼠的眼前房。在最初的实验中，我们发现来自E15及更大胎儿的移植组织通常会分化为具有广泛神经毡的神经元区域，其外观类似于前下丘脑区域。在该组织中仅偶尔观察到成组的、紧密排列的小神经元。对这些移植组织的超微结构分析通常显示出分化良好的神经元胞体和具有复杂突触组织的神经毡，其外观与正常大鼠前下丘脑区域相似。在一些移植组织中偶尔会同时存在成熟和未成熟组织。来自年轻胚胎（E12 - 14）的组织经常显示出具有SCN细胞构筑外观的紧密、小神经元核的发育。在这种情况下，移植后至少需要45天才能成功分化。这些移植组织中的SCN显示出血管活性肠肽免疫反应性细胞和纤维，周围环绕着加压素免疫反应性细胞和纤维，类似于在正常成年SCN中观察到的模式。我们的结果表明，前下丘脑在眼内会正常分化，并且SCN的表型特化在其组成神经元出生之前就已发生。
