Hypothalamic Projections to the Raphe Nuclei of the Medulla oblongata.

本研究采用顺行和逆行标记技术来阐明大鼠下丘脑向中缝髓核的下行投射。顺行标记技术。少量[<^3H>]亮氨酸单侧注射到下丘脑的各个部位。在下丘脑室旁核尾侧下丘脑背后区注射后，在白条核、锥体束静脉面和下舌束间核双侧可见丰富的特征性末端标记。在中缝隐核和同侧中缝大核中观察到明显但数量较少的标记。逆行标记技术。在中缝白白核注射WGA-HRP后，在下丘脑背侧腹内侧发现许多标记小神经元（6-13X9-22 <微> m），呈椭圆形。在通过下丘脑背内侧核的水平上，它们形成了一个明显而致密的细胞团。脊髓注射HRP后，标记神经元主要分布在下丘脑背侧背侧，大小较大（9-22X11-36 <微> m），呈椭圆形和三角形。在双标记实验中，分别在中缝苍白核和脊髓注射Fast Blue或True Blue和Nuclear Yellow。大量的蓝色荧光神经元主要位于下丘脑背区腹内侧，黄色荧光神经元主要位于下丘脑背区背侧。这些结果表明，下丘脑背区直接投射到中缝苍白核，投射到脊髓的神经元与投射到中缝苍白核的神经元不同。

The present study was undertaken using the anterograde and retograde labeling techniques to clarify the hypothalamic descending projections tothe medullary raphe nuclei in the rat.1. Anterograde labeling technique. A small amount of [ <^3H> ] leucine was injected unilaterally into various parts of the hypothalamus. Abundant and characteristic terminal labelings were observed bialterally in the nucleus raphe pallidus, the vental surface of the pyramidal tract and the nucleus interfascicularis hypoglossi, after injections into the dorsal posterior hypothalamic area caudal to the paraventricular hypothalamic nucleus. Conspicuous, but less numerous labelings were observed in the nucleus raphe obscurus and the ipsilateral raphe magnus.2. Retrograde labeling techniques. Following an injection of WGA-HRP in the nucleus raphe pallidus many labelled smalll neurons (6-13X9-22 <micro> m) with an oval shape were found in the ventromedial part of the dorsal hypothalamic area. At the level through the dorsomedial hypothalamic nucleus, they formed a distinct and compact cell cluster. Labelled neurons, which were large in size (9-22X11-36 <micro> m) with oval and triangular shapes, were found mainly in the dorsolateal part of the dorsal hypothalamic area after injections of HRP in the spinal cord. In a double-labeling experiment, Fast Blue or True Blue, and Nuclear Yellow were injected in the nucleus raphe pallidus and the spinal cord, respectively. A large number of blue-fluorescent neurons were located mostly in the ventromedial part of the dorsal hypothalamic area, while yellow-fluorescent ones were found in the dorsolateal part of the dorsal hypothalamic area.These results show that the dorsal hypothalamic area projects directly to the nucleus raphe pallidus, and that the neurons which project to the spinal cord differ from those which project to the nucleus raphe pallidus.