Sollars P J, Pickard G E
Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Chronobiol Int. 1998 Sep;15(5):513-33. doi: 10.3109/07420529808998705.
Destruction of the hypothalamic suprachiasmatic nucleus (SCN) disrupts circadian behavior. Transplanting SCN tissue from fetal donors into SCN-lesioned recipients can restore circadian behavior to the arrhythmic hosts. In the transplantation model employing fetal hamster donors and SCN-lesioned hamsters as hosts, the period of the restored circadian behavior is hamster-typical. However, when fetal rat anterior hypothalamic tissue containing the SCN is implanted into SCN-lesioned rats, the period of the restored circadian rhythm is only rarely typical of that of the intact rat. The use of an anterior hypothalamic heterograft model provides new approaches to donor specificity of restored circadian behavior and with the aid of species-specific markers, provides a means for assessing connectivity between the graft and the host. Using an antibody that stains rat and mouse neuronal tissue but not hamster neurons, it has been demonstrated that rat and mouse anterior hypothalamic heterografts containing the SCN send numerous processes into the host (hamster) neuropil surrounding the graft, consistent with graft efferents reported in other hypothalamic transplantation models in which graft and host tissue can be differentiated (i.e., Brattleboro rat and hypogonadal mouse). Moreover, SCN neurons within anterior hypothalamic grafts send an appropriately restricted set of efferent projections to the host brain which may participate in the functional recovery of circadian locomotor activity.
下丘脑视交叉上核（SCN）的破坏会扰乱昼夜节律行为。将来自胎儿供体的SCN组织移植到SCN损伤的受体中，可以使节律紊乱的宿主恢复昼夜节律行为。在使用胎儿仓鼠供体和SCN损伤的仓鼠作为宿主的移植模型中，恢复的昼夜节律行为的周期是仓鼠典型的。然而，当将含有SCN的胎儿大鼠下丘脑前部组织植入SCN损伤的大鼠中时，恢复的昼夜节律的周期很少是完整大鼠的典型周期。下丘脑前部异种移植模型的使用为恢复的昼夜节律行为的供体特异性提供了新方法，并借助物种特异性标记物，提供了一种评估移植物与宿主之间连接性的手段。使用一种能对大鼠和小鼠神经元组织染色但不能对仓鼠神经元染色的抗体，已证明含有SCN的大鼠和小鼠下丘脑前部异种移植物向移植物周围的宿主（仓鼠）神经毡发出许多突起，这与其他下丘脑移植模型中报道的移植物传出纤维一致，在这些模型中移植物和宿主组织可以区分（即布拉特洛维大鼠和性腺功能减退小鼠）。此外，下丘脑前部移植物中的SCN神经元向宿主脑发出一组适当受限的传出投射，这可能参与昼夜运动活动的功能恢复。
