Cagampang F R, Yang J, Nakayama Y, Fukuhara C, Inouye S T
Laboratory of Integrative Brain Function, Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo, Japan.
Brain Res Mol Brain Res. 1994 Jul;24(1-4):179-84. doi: 10.1016/0169-328x(94)90130-9.
Arginine-vasopressin (AVP) gene expression in the rat suprachiasmatic nucleus (SCN) is subject to daily rhythmic changes. To determine whether this variation is endogenously generated, temporal changes in the SCN AVP mRNA level in constant dark (DD) condition was compared with changes occurring under the light-dark (LD) condition. In both lighting conditions, the presence of a rhythm in AVP mRNA level was observed in the SCN. In LD condition, peak level of AVP mRNA was found during the latter part of the day (zeitgeber time or ZT 8) and trough value during the night at ZT 20. Correspondingly, peak level of AVP mRNA under DD condition was observed during the latter part of the subjective day (circadian time or CT 8) and a trough during the subjective night (CT 20). Under both lighting conditions, a rapid increase and decrease of mRNA around the peak time was also observed. On the other hand, no significant daily variation in AVP mRNA was found in the supraoptic nucleus in both LD and DD conditions. These results provide evidence that a rhythmic change in AVP mRNA level is regulated by a circadian clock intrinsic to the SCN. The phase relationship of AVP mRNA rhythm to peptide rhythm in the SCN is discussed.
大鼠视交叉上核（SCN）中精氨酸加压素（AVP）基因的表达呈现出每日节律性变化。为了确定这种变化是否是内源性产生的，将持续黑暗（DD）条件下SCN中AVP mRNA水平的时间变化与明暗（LD）条件下发生的变化进行了比较。在两种光照条件下，均在SCN中观察到AVP mRNA水平存在节律。在LD条件下，AVP mRNA的峰值出现在一天的后半段（授时时间或ZT 8），而谷值出现在夜间的ZT 20。相应地，在DD条件下，AVP mRNA的峰值出现在主观日的后半段（昼夜时间或CT 8），谷值出现在主观夜间（CT 20）。在两种光照条件下，在峰值时间左右还观察到mRNA的快速上升和下降。另一方面，在LD和DD条件下，视上核中AVP mRNA均未发现明显的每日变化。这些结果提供了证据，表明AVP mRNA水平的节律性变化受SCN内在生物钟的调节。本文还讨论了SCN中AVP mRNA节律与肽节律的相位关系。
