Deurveilher Samuel, Semba Kazue
Department of Anatomy and Neurobiology, Faculty of Medicine, Dalhousie University, 5850 College Street, NS B3H 1X5, Halifax, Canada.
Brain Res. 2003 Oct 10;987(1):100-6. doi: 10.1016/s0006-8993(03)03295-5.
We recently showed, using dual tract-tracing, that the suprachiasmatic nucleus (SCN), the site of the principal circadian clock in mammals, may have indirect projections to the sleep-promoting ventrolateral preoptic nucleus (VLPO) via relays in the medial preoptic area (MPA), dorsomedial hypothalamic nucleus (DMH), and, to a lesser extent, the subparaventricular zone (SPVZ). Here, we found that the injection of the rostral MPA, the periventricular nucleus/medial SPVZ, and the caudal DMH with a mixture of anterograde and retrograde tracers resulted in dense anterograde labeling in the median preoptic nucleus (MnPO), another key sleep-promoting nucleus in the preoptic region. The retrograde labeling in the SCN was evident as previously reported. The injections in either the MPA or the DMH produced similar densities of varicose fibers between the MnPO and the VLPO, while the injections in the SPVZ yielded a greater density of varicose fibers in the MnPO than in the VLPO. These results suggest that the MPA and DMH are potential relay nuclei to mediate SCN output to the MnPO, as well as to the VLPO, for the circadian control of sleep-wake states.
我们最近利用双束示踪法表明，哺乳动物主要昼夜节律钟所在的视交叉上核（SCN）可能通过内侧视前区（MPA）、下丘脑背内侧核（DMH）以及程度较轻的室旁下区（SPVZ）的中继，间接投射到促进睡眠的腹外侧视前核（VLPO）。在此，我们发现，向头端MPA、室周核/内侧SPVZ以及尾端DMH注射顺行和逆行示踪剂混合物后，在视前正中核（MnPO）出现了密集的顺行标记，MnPO是视前区另一个促进睡眠的关键核团。SCN中的逆行标记如先前报道的那样明显。向MPA或DMH注射示踪剂后，MnPO和VLPO之间曲张纤维的密度相似，而向SPVZ注射示踪剂后，MnPO中曲张纤维的密度高于VLPO。这些结果表明，MPA和DMH是潜在的中继核，可介导SCN向MnPO以及VLPO的输出，以实现昼夜节律对睡眠-觉醒状态的控制。
