Harada S, Imaki T, Chikada N, Naruse M, Demura H
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Brain Res. 1999 Mar 13;821(2):322-32. doi: 10.1016/s0006-8993(99)01124-5.
Nitric oxide (NO) is known to be involved in the modulation of neuroendocrine function. To clarify the role of different isoforms of NO synthase (NOS) in the neuroendocrine response to immune challenge, the expressions of neuronal NOS (nNOS) and inducible NOS (iNOS) genes in the hypothalamus following lipopolysaccharide (LPS) injection were examined using in situ hybridization. NOS activity was also determined by NADPH-diaphorase (NADPH-d) histochemistry. LPS (25 mg/kg) or sterile saline was injected intraperitoneally to male Wistar rats and the rats sacrificed 30 min, or 1, 2, 3, 5, 12 or 24 h after injection. nNOS mRNA expression in the paraventricular nucleus (PVN) was significantly increased 2 h after LPS injection. iNOS mRNA, which was not detected until 2 h after LPS injection, was significantly increased in the PVN 3 h after LPS injection. Both RNA expressions had returned to basal levels by 12 h after LPS injection. The number of NADPH-d positive cells was significantly increased 5 h after LPS injection. iNOS expression was more robust in parvocellular PVN, while nNOS was distributed mainly in the magnocellular PVN. Double in situ hybridization histochemistry revealed that some of the iNOS- (48.4%) or nNOS-positive cells (34. 3%) in the parvocellular PVN expressed CRF mRNA. The results demonstrate that LPS-induced sepsis causes significant increases in nNOS and iNOS gene expression with different time-courses and distributions, and that iNOS mRNA was more frequently co-localized with CRF-producing parvocellular neurons in the PVN. Thus, NO produced by iNOS and nNOS may play an important role in the neuroendocrine response to an immune challenge. Distinct differences in the distribution and time-course changes of iNOS and nNOS suggest different roles for the hypothalamic-pituitary-adrenal axis and/or neurohypophyseal system.
已知一氧化氮（NO）参与神经内分泌功能的调节。为阐明一氧化氮合酶（NOS）不同同工型在免疫应激神经内分泌反应中的作用，采用原位杂交技术检测了脂多糖（LPS）注射后下丘脑神经元型NOS（nNOS）和诱导型NOS（iNOS）基因的表达。还通过NADPH-黄递酶（NADPH-d）组织化学法测定了NOS活性。将LPS（25mg/kg）或无菌生理盐水腹腔注射给雄性Wistar大鼠，并在注射后30分钟、1、2、3、5、12或24小时处死大鼠。LPS注射后2小时，室旁核（PVN）中nNOS mRNA表达显著增加。LPS注射后2小时才检测到的iNOS mRNA，在LPS注射后3小时在PVN中显著增加。LPS注射后12小时，两种RNA表达均恢复到基础水平。LPS注射后5小时，NADPH-d阳性细胞数量显著增加。iNOS表达在小细胞性PVN中更强，而nNOS主要分布在大细胞性PVN中。双重原位杂交组织化学显示，小细胞性PVN中一些iNOS阳性细胞（48.4%）或nNOS阳性细胞（34.3%）表达促肾上腺皮质激素释放因子（CRF）mRNA。结果表明，LPS诱导的脓毒症导致nNOS和iNOS基因表达随时间进程和分布的显著增加，且iNOS mRNA更频繁地与PVN中产生CRF的小细胞神经元共定位。因此，iNOS和nNOS产生的NO可能在免疫应激的神经内分泌反应中起重要作用。iNOS和nNOS在分布和时间进程变化上的明显差异提示下丘脑-垂体-肾上腺轴和/或神经垂体系统具有不同作用。
