Smale L, Blanchard J, Moore R Y, Morin L P
Department of Psychiatry, State University of New York, Stony Brook 11794.
Brain Res. 1991 Nov 1;563(1-2):77-86. doi: 10.1016/0006-8993(91)91517-5.
The suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) are retinorecipient structures that play important roles in the expression of circadian rhythmicity. We examined these two structures in a diurnal ground squirrel, Spermophilus lateralis, using immunohistochemical techniques, and cholera toxin-bound horseradish peroxidase. A number of immunoreactive substances are distributed within the ground squirrel SCN in a pattern similar to that reported in many other mammals. These include vasopressin, vasoactive intestinal polypeptide, serotonin, neuropeptide Y (NPY), and glial fibrillary acidic protein. The squirrel SCN differs from that of most other species examined to date in two respects. First, a dense cluster of cells containing immunoreactive L-enkephalin (L-ENK-IR) is observed in the center of the SCN. Second, there is a contralateral, but no ipsilateral, projection from the retina to the SCN. In the lateral geniculate region there is a substantial region that contains NPY-immunoreactive cells and receives a bilateral retinal projection. This region is assumed to be homologous with the IGL described in other mammals. Cells containing L-ENK-IR are distributed throughout the LGN in groups that overlap, but which have a distinctly different distribution than the more extensive groups of NPY-IR cells.
视交叉上核（SCN）和膝间小叶（IGL）是视网膜接受结构，在昼夜节律性表达中起重要作用。我们使用免疫组织化学技术和霍乱毒素结合辣根过氧化物酶，在一种昼行性地松鼠（侧纹黄鼠）中检查了这两个结构。许多免疫反应性物质以与许多其他哺乳动物中报道的模式相似的方式分布在松鼠的视交叉上核内。这些物质包括血管加压素、血管活性肠多肽、5-羟色胺、神经肽Y（NPY）和胶质纤维酸性蛋白。松鼠的视交叉上核在两个方面与迄今为止检查的大多数其他物种不同。首先，在视交叉上核的中心观察到一群密集的含有免疫反应性亮氨酸脑啡肽（L-ENK-IR）的细胞。其次，从视网膜到视交叉上核存在对侧投射，但没有同侧投射。在外侧膝状体区域，有一个相当大的区域含有NPY免疫反应性细胞，并接受双侧视网膜投射。该区域被认为与其他哺乳动物中描述的膝间小叶同源。含有L-ENK-IR的细胞成群分布在整个外侧膝状体核中，这些群相互重叠，但分布与更广泛的NPY-IR细胞群明显不同。
