Aguilar-Roblero R, Drucker-Colín R, Moore R Y
Departamento de Neurociencias, Universidad Nacional Autónoma de México, D.F.
Chronobiol Int. 1992 Aug;9(4):278-96. doi: 10.3109/07420529209064538.
We have studied the effects of fetal neuronal grafts on the temporal pattern of drinking behavior of suprachiasmatic nuclei (SCN)-lesioned adult rats. Additionally, in an independent set of animals, the immunohistochemical staining for vasopressin, vasoactive intestinal polypeptide, and neuropeptide Y and the retinal connections to the hypothalamus were studied. The behavioral experiments indicate that anterior hypothalamic transplants induced reorganization of the temporal pattern of drinking behavior when placed in the third ventricle of adult hosts bearing complete SCN lesions, but not when placed in a cavity in the occipital cortex. Such rhythmicity persists only when the animals were recorded under constant darkness but not under constant light, indicating that the restored rhythmicity was generated endogenously but that the oscillator was extremely sensitive to light. Fetal occipital cortex induced reorganization of the temporal pattern of previously arrhythmic hosts, but it disappeared when the animals were recorded under constant light or constant darkness. It is clear that this rhythmicity was exogenous. In contrast to the cortical transplants, the hypothalamic transplants showed a morphological organization similar to that found in the normal hypothalamus regardless of their placement in the host brain. From these observations it is concluded that development of neocortex is more affected by environmental factors than that of the hypothalamus. Both hypothalamic and cortical transplants induced sprouting of retinal fibers into the anterior hypothalamus and the grafted tissue. It is possible that such fibers could be the neuroanatomical substrate by which rhythmicity is induced by cortical tissue.
我们研究了胎儿神经元移植对损毁视交叉上核（SCN）的成年大鼠饮水行为时间模式的影响。此外，在另一组独立的动物中，研究了抗利尿激素、血管活性肠多肽、神经肽Y的免疫组织化学染色以及视网膜与下丘脑的连接。行为实验表明，将下丘脑前部移植体置于完全损毁SCN的成年宿主的第三脑室时，可诱导饮水行为时间模式的重组，但置于枕叶皮质的腔隙中时则不然。只有在持续黑暗条件下记录动物时，这种节律性才会持续，而在持续光照条件下则不会，这表明恢复的节律性是内源性产生的，但振荡器对光极为敏感。胎儿枕叶皮质可诱导先前无节律宿主的时间模式重组，但在持续光照或持续黑暗条件下记录动物时，这种重组消失。显然，这种节律性是外源性的。与皮质移植不同，无论置于宿主脑内何处，下丘脑移植都显示出与正常下丘脑相似的形态组织。从这些观察结果可以得出结论，新皮质的发育比下丘脑更容易受到环境因素的影响。下丘脑和皮质移植均诱导视网膜纤维向前部下丘脑和移植组织内生长。这些纤维有可能是皮质组织诱导节律性的神经解剖学基础。
