Reuss S, Bürger K
Department of Anatomy, Johannes Gutenberg-University, Mainz, Germany.
Brain Res. 1994 Feb 28;638(1-2):189-95. doi: 10.1016/0006-8993(94)90649-1.
The immunohistochemical distribution of substance P (SP) in the hypothalamic suprachiasmatic nucleus (SCN) was studied in adult male and female Djungarian hamsters (Phodopus sungorus) held under either long or short photoperiods. Intact animals were killed by perfusion with a fixative at the middle of the light or dark periods, respectively. The tissue was processed by routine immunohistochemical methods. Perikarya exhibiting SP-like immunoreactivity (LI) were found in the SCN of animals of all groups. These cell bodies predominantly were restricted to a distinct portion of the nucleus extending less than 150 microns rostrocaudally and were often concentrated in its lateral aspect. SP-LI fibers were rarely observed in the SCN, however, other hypothalamic parts, e.g. anterior and paraventricular regions, exhibit strong SP-LI innervation patterns. Sex-related differences were not observed. Long-term exposure to short days decreased the number of neurons exhibiting SP-LI by approximately 60% when compared to long-day animals at both day- and nighttime. At night, SP-LI neurons were augmented in number by 34% (long-day group) and 56% (short-day group). Further, the numbers of SP-LI perikarya in the SCN of aged hamsters at day- and nighttime were augmented 3- to 4-fold when compared to adult animals. These results suggest that substance P in the SCN is involved in the regulation of circadian and seasonal mechanisms in this highly photoperiodic rodent species.
研究了长日照或短日照条件下成年雄性和雌性黑线毛足鼠下丘脑视交叉上核（SCN）中P物质（SP）的免疫组织化学分布。分别在光照期或黑暗期的中间，通过灌注固定剂处死完整的动物。组织采用常规免疫组织化学方法处理。在所有组动物的SCN中均发现了呈现SP样免疫反应性（LI）的神经元胞体。这些细胞体主要局限于核内一个明显的部分，其前后延伸小于150微米，且常集中于其外侧。然而，在SCN中很少观察到SP-LI纤维，而其他下丘脑部分，如前部和室旁区域，则呈现出强烈的SP-LI神经支配模式。未观察到性别相关差异。与长日照动物相比，长期暴露于短日照条件下，无论是在白天还是夜间，呈现SP-LI的神经元数量减少了约60%。在夜间，SP-LI神经元数量在长日照组增加了34%，在短日照组增加了56%。此外，与成年动物相比，老年仓鼠在白天和夜间SCN中SP-LI胞体的数量增加了3至4倍。这些结果表明，SCN中的P物质参与了这种高度光周期啮齿动物物种的昼夜节律和季节性机制的调节。
