Sharp F R, Sagar S M, Hicks K, Lowenstein D, Hisanaga K
Department of Neurology, University of California, San Francisco.
J Neurosci. 1991 Aug;11(8):2321-31. doi: 10.1523/JNEUROSCI.11-08-02321.1991.
The induction of c-fos mRNA was assessed using Northern blots and in situ hybridization in adult rats administered hypertonic saline (HS) and isotonic saline (IS). HS induced c-fos mRNA in magnocellular paraventricular nucleus (PVNm), parvocellular paraventricular nucleus (PVNp), supraoptic nucleus (SON), and lamina terminalis (LMT). This occurred within 5 min, peaked at 30-60 min, and disappeared by 180 min. Fos protein, detected using a specific monoclonal antibody, was maximal at 1-2 hr and disappeared 4-8 hr after HS administration. This confirms observations showing that the c-fos gene response is transient even in the presence of a continuing stimulus. In contrast, Fos-like immunoreactivity (FLI), detected using two polyclonal antisera, was observed in PVNm, PVNp, SON, and LMT for 1-24 hr during continuous osmotic stimulation. Moreover, FLI was observable in these structures for 7 d in rats administered HS and allowed to drink water ad libitum beginning 24 hr later. At times greater than 8 hr, FLI presumably represents Fos-related antigens (FRA), proteins immunologically and functionally related to Fos, whose expression is much more prolonged than authentic Fos following the osmotic stimulus. In addition to induction of c-fos expression in regions specifically involved in osmotic regulation, HS injections also induced c-fos in many other forebrain regions. In order to assess the induction of c-fos mRNA due to the "stress" of the injections, rats injected with isotonic saline were compared to uninjected controls. Isotonic saline injections induced c-fos mRNA in the PVNp, anterior hypothalamus, suprachiasmatic nucleus, cingulate gyrus, neocortex, ventral lateral septal nucleus, piriform cortex, hippocampal pyramidal and dentate granule neurons, paraventricular and intralaminar thalamic nuclei, bed nuclei of stria terminalis, cortical and medial amygdaloid nuclei, and other structures. In accord with other work, we interpret this pattern of c-fos expression to result from the stress of handling and injections. Since Fos and FRA probably bind to the promoters of target genes and regulate their expression, they likely mediate biochemical changes in the cells activated by the osmotic and stressful stimuli. Whereas the Fos signal is transient, FRA may act on target genes for the duration of the stimulus or longer.
在给成年大鼠注射高渗盐水（HS）和等渗盐水（IS）后，使用Northern印迹法和原位杂交技术评估c-fos mRNA的诱导情况。HS诱导了大细胞室旁核（PVNm）、小细胞室旁核（PVNp）、视上核（SON）和终板（LMT）中c-fos mRNA的表达。这种诱导在5分钟内发生，30 - 60分钟达到峰值，180分钟后消失。使用特异性单克隆抗体检测到的Fos蛋白在注射HS后1 - 2小时达到最大值，4 - 8小时后消失。这证实了即使在持续刺激存在的情况下，c-fos基因反应也是短暂的这一观察结果。相比之下，使用两种多克隆抗血清检测到的Fos样免疫反应性（FLI）在持续渗透刺激期间，在PVNm、PVNp、SON和LMT中持续1 - 24小时。此外，在注射HS并在24小时后允许自由饮水的大鼠中，这些结构中可观察到FLI长达7天。在大于8小时时，FLI可能代表Fos相关抗原（FRA），即与Fos在免疫和功能上相关的蛋白质，其表达在渗透刺激后比真正的Fos持续时间长得多。除了在专门参与渗透调节的区域诱导c-fos表达外，HS注射还在许多其他前脑区域诱导了c-fos表达。为了评估由于注射“应激”导致的c-fos mRNA诱导情况，将注射等渗盐水的大鼠与未注射的对照大鼠进行比较。等渗盐水注射在PVNp、下丘脑前部、视交叉上核、扣带回、新皮层、腹侧外侧隔核、梨状皮层、海马锥体细胞和齿状颗粒神经元、室旁和板内核、终纹床核、皮质和内侧杏仁核以及其他结构中诱导了c-fos mRNA的表达。与其他研究一致，我们将这种c-fos表达模式解释为处理和注射应激的结果。由于Fos和FRA可能与靶基因的启动子结合并调节其表达，它们可能介导了由渗透和应激刺激激活的细胞中的生化变化。虽然Fos信号是短暂的，但FRA可能在刺激持续期间或更长时间内作用于靶基因。
