NEURONAL-ACTIVITY AND NEUROPEPTIDE GENE-TRANSCRIPTION IN THE BRAINS OF IMMUNE-CHALLENGED RATS
NEURONAL-ACTIVITY AND NEUROPEPTIDE GENE-TRANSCRIPTION IN THE BRAINS OF IMMUNE-CHALLENGED RATS
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DOI：
10.1111/j.1365-2826.1995.tb00788.x
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发表时间：
1995-07-01
影响因子：
3.2
通讯作者：
LAFLAMME, N
中科院分区：
文献类型：
--
作者：
RIVEST, S;LAFLAMME, N
本研究探讨了急性期反应的系统性免疫激活对各种即时早期基因（IEGs）和神经肽在清醒大鼠脑中的转录的影响。在单次腹膜内（i. p.）给药免疫活化剂脂多糖（LPS）或载体溶液后，处死成年雄性大鼠，将其脑切成30 μ m冠状切片。用S-35标记的核糖核酸探针原位杂交组织化学法检测编码IEGs c-fos和神经生长因子诱导B（NGFI-B）以及神经肽促肾上腺皮质激素释放因子（CRF）、催产素（OT）和加压素（AVP）的mRNA。这些神经肽的初级转录本（hernRNA）也被检测到使用内含子探针技术，和c-fos mRNA的共定位CRF，AVP，OT神经元内的免疫细胞化学和原位杂交技术相结合的手段确定在相同的脑切片。LPS处理后1h，下丘脑室旁核（PVN）小细胞区c-fos和NGFI-B基因均表达。内侧视前区/终板的血管器，视上核（SON），PVN的大细胞分裂，弓状核/正中隆起，蓝斑，孤束核，和最后区也表现出这两个成绩单3小时后内毒素管理的强信号。在下丘脑背内侧区、杏仁核中央核、结节乳头核腹侧部、被盖背外侧核、臂旁核外侧部、疑核背侧部和外侧网状核等结构中，c-fos表达量较小，但表达量明显。大部分脑核团c-fos和NGFI-B mRNA在注射LPS后3 h达高峰，6 h下降，9 ~ 12 h消失。在PVN的小细胞核中，c-fos主要表达在CRF免疫反应（IR）神经元中，而在该核的大细胞部分和SON中，该转录物共定位于许多OT-IR和少数AVP-IR神经元中。小细胞PVN中CRF mRNA的相对水平也显着增加6小时后LPS，但内毒素并没有改变这种压力相关的神经肽在其他脑区的基因表达。CRF初级转录物（hnRNA）证实了这一点，它只在PVN中表达，而不是在LPS处理的大鼠脑中的任何其他核中。虽然AVP和OT的mRNA水平没有显着改变，无论是在PVN或SON的免疫攻击的大鼠，因为在这些核中的每个转录物的高基础水平，LPS引起显着的诱导AVP hnRNA的parvoPVN。这些结果提供了证据表明，腹腔内注射内毒素可在脑的选择性结构中产生各种IEG转录物的强烈活化，这反过来可能在免疫输入整合到中枢神经系统中起决定性作用。这是可能的，刺激参与控制下丘脑-垂体-肾上腺轴在免疫挑战过程中的下丘脑核团的神经肽生物合成是这种整合的重要步骤。
The present study investigated the effect of the acute-phase response of a systemic immune activation on the transcription of various immediate early genes (IEGs) and neuropeptides in the brain of conscious rats. One, 3, 6, 9, and 12 h after a single intraperitoneal (i.p.) administration of either the immune activator lipopolysaccharide (LPS) or the vehicle solution, adult male rats were sacrificed and their brains cut in 30-mu m coronal sections. mRNA encoding the IEGs c-fos and nerve growth factor inducible-B (NGFI-B), and neuropeptides corticotropin-releasing factor (CRF), oxytocin (OT), and vasopressin (AVP) were assayed by in situ hybridization histochemistry using a S-35-labeled riboprobes. The primary transcripts (heteronuclear (hn)RNA) for these neuropeptides were also detected using intronic probe technology, and colocalization of c-fos mRNA within CRF, AVP, and OT neurons was determined by means of a combination of immunocytochemistry and in situ hybridization techniques on same the brain sections. One h after LPS treatment, both c-fos and NGFI-B genes were expressed in the parvocellular division of the paraventricular nucleus (PVN) of the hypothalamus. The medial preoptic area/organum vasculosum of the lamina terminalis, the supraoptic nucleus (SON), the magnocellular division of the PVN, the arcuate nucleus/median eminence, the locus coeruleus, the nucleus of the solitary tract, and the area postrema also exhibited a strong signal for these two transcripts 3 h after endotoxin administration. A smaller but a significant c-fos expression was observed in various structures, including the dorsomedial hypothalamic area, the central nucleus of the amygdala, the ventral part of the tuberomammillary nucleus, the laterodorsal tegmental nucleus, the external lateral part of the parabrachial nucleus, the dorsal division of the ambiguus nucleus, and the lateral reticular nucleus of LPS-injected rats. The signal for c-fos and NGFI-B mRNA in most of these brain nuclei reached a maximum at 3 h postinjection, declined at 6 h, and vanished 9 to 12 h after LPS treatment. In the parvocellular nucleus of the PVN, c-fos was largely expressed in CRF-immunoreactive (ir) neurons, whereas in the magnocellular part of that nucleus and in the SON, this transcript was colocalized in numerous OT-ir and few AVP-ir neurons. Relative levels of CRF mRNA in the parvocellular PVN were also significantly increased 6 h following LPS, but endotoxin did not alter the genetic expression of this stress-related neuropeptide in other brain regions. This was confirmed by the CRF primary transcript (hnRNA), which was expressed only in the PVN but not in any other nucleus in the brains of LPS-treated rats. Although AVP and OT mRNA levels were not significantly altered in either the PVN or the SON of immune-challenged rats because of the high basal levels of each transcript in these nuclei, LPS caused significant induction of AVP hnRNA in the parvoPVN. These results provide evidence that i.p. endotoxin administration can produce a strong activation of various IEG transcripts in selective structures of the brain, which could in turn play a determinant role in the integration of immune input to the central nervous system. It is possible that the stimulation of neuropeptide biosynthesis in the hypothalamic nuclei involved in the control of the hypothalamic-pituitary adrenal axis during immune challenge is an important step in this integration.