Lehman M N, Silver R, Gladstone W R, Kahn R M, Gibson M, Bittman E L
J Neurosci. 1987 Jun;7(6):1626-38. doi: 10.1523/JNEUROSCI.07-06-01626.1987.
It is well established that overt circadian rhythms are permanently disrupted following lesions of the hamster hypothalamic suprachiasmatic nucleus (SCN). In the present study, we show that implantations of brain grafts containing the fetal SCN reestablish circadian rhythms of locomotor activity in adult hamsters previously made arrhythmic by SCN lesions. The restoration of free-running rhythms in conditions of constant darkness is correlated with the presence in the graft of neuropeptides normally present in the SCN of unlesioned hamsters, including vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), and vasopressin (VP). In several recipients, grafts were found to receive retinal input, and appeared to send efferents into the host brain. Not all functions of the SCN were reinstated by the graft: animals with restored locomotor rhythms did not show gonadal regression in the absence of light, and failed to synchronize (entrain) to light intensities to which SCN-intact animals responded.
众所周知，仓鼠下丘脑视交叉上核（SCN）受损后，明显的昼夜节律会被永久性破坏。在本研究中，我们发现，将含有胎儿SCN的脑移植片植入成年仓鼠后，这些仓鼠此前因SCN损伤而失去节律的运动活动昼夜节律得以重建。在持续黑暗条件下自由运行节律的恢复与移植片中存在正常情况下未受损仓鼠SCN中含有的神经肽有关，这些神经肽包括血管活性肠肽（VIP）、神经肽Y（NPY）和加压素（VP）。在一些受体中，发现移植片接受视网膜输入，并且似乎向宿主脑发出传出纤维。移植片并未恢复SCN的所有功能：运动节律恢复的动物在无光照时未出现性腺退化，并且未能与SCN完整的动物所响应的光照强度同步（同步化）。
