Sumová Alena, Illnerová Helena
Department of Neurohumoral Regulations, Institute of Physiology, Academy of Sciences of Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
Brain Res. 2005 Jun 28;1048(1-2):161-9. doi: 10.1016/j.brainres.2005.04.061.
To ascertain how photic stimuli disturbing overt circadian rhythms affect the endogenous rhythmicity of the suprachiasmatic nucleus (SCN), rats were subjected to constant light (LL) or to a 9-h light pulse encompassing midnight, and rhythms of abundance of the c-Fos-immunoreactive (c-Fos-ir) and the PER1-immunoreactive (PER1-ir) cells were studied during the first 1-2 cycles following release into LL or darkness (DD) within the whole SCN as well as in its ventrolateral (vl) and the dorsomedial (dm) part. LL seemingly abolished the c-Fos rhythm in the whole SCN, while the rhythm persisted in the vl- and dm-SCN. In the dm-SCN, the rhythm of c-Fos-ir was phase-delayed by about 4 h in LL, whereas the rhythm of PER1-ir was affected just slightly. In the vl-SCN, the rhythm of c-Fos photo-induction might be delayed by 5-6 h as compared with the reported rhythm [A. Sumova and H. Illnerova, Am. J. Physiol. 274 (1998) R857-R863], whereas the PER1 profile appeared to be out of phase with that in DD. After a 9-h light pulse encompassing midnight, the rhythm of PER1-ir in the dm-SCN changed just slightly, whereas the PER1 rhythm in the vl-SCN was abolished and there was just an indication of extension of elevated PER1-ir. Altogether, the data indicate that photic stimuli disturbing circadian rhythms affect more dramatically the vl- than the dm-SCN rhythmicity within the first cycles and that in the dm-SCN shifting of the c-Fos rhythm proceeds more rapidly than that of the Per1 rhythm.
为了确定干扰明显昼夜节律的光刺激如何影响视交叉上核（SCN）的内源性节律，将大鼠置于持续光照（LL）或包含午夜的9小时光脉冲环境中，并在整个SCN以及其腹外侧（vl）和背内侧（dm）部分释放到LL或黑暗（DD）后的前1 - 2个周期内，研究c-Fos免疫反应性（c-Fos-ir）和PER1免疫反应性（PER1-ir）细胞丰度的节律。LL似乎消除了整个SCN中的c-Fos节律，而该节律在vl-SCN和dm-SCN中持续存在。在dm-SCN中，LL条件下c-Fos-ir的节律相位延迟约4小时，而PER1-ir的节律仅受到轻微影响。在vl-SCN中，与报道的节律相比，c-Fos光诱导的节律可能延迟5 - 6小时[A. Sumova和H. Illnerova，《美国生理学杂志》274（1998）R857 - R863]，而PER1的分布似乎与DD中的情况不同步。在包含午夜的9小时光脉冲后，dm-SCN中PER1-ir的节律变化轻微，而vl-SCN中的PER1节律被消除，仅显示出PER1-ir升高有延长的迹象。总之，数据表明，干扰昼夜节律的光刺激在最初的周期内对vl-SCN节律性的影响比对dm-SCN节律性的影响更显著，并且在dm-SCN中，c-Fos节律的变化比Per1节律的变化更快。
