Gene cascades in cell differentiation and plasticity

一氧化氮合成酶（NOS）有神经元型、诱导型和覆盖型三种同工型。eNOS和nNOS在中枢神经系统中组成性表达，参与神经元活动和神经元退行性疾病。采用地高辛标记的互补RNA探针，采用非放射性同位素原位杂交技术检测大鼠脑内表达nNOS mRNA的神经元的区域分布。在主要嗅球和副嗅球、胼胝体岛、杏仁核、丘脑室旁核、几个下丘脑核、外侧膝状核、后联合的大细胞核、上丘和下丘、侧背核和桥脚被盖核、梯形体核等离散区域观察到强烈阳性神经元的聚集。孤立束核和小脑。强染色的离体神经元主要分布于大脑皮层、基底节区和脑干，尤以髓质网状结构为主。在海马下丘脑，在齿状回颗粒细胞层和阿蒙角锥体细胞层中观察到中等染色的神经元几乎均匀分布，而在整个海马区域中观察到较强染色的孤立神经元。这些结果为神经元型一氧化氮合酶的功能和基因调控研究提供了良好的基础。

There are three isoforms of nitric oxide synthase (NOS), neuronal nNOS, inducible iNOS and enclotherial eNOS.eNOS and nNOS are expressed constitutively in CNS and are involved in neuronal activities and neuronal degenerative diseases. Regional distribution of neurons expressing nNOS mRNA in the rat brain was examined by non-radioisotope in situ hybridization, using digoxigenin-labeled complementary RNA probes. Clustering of intensely positive neurons was observed in discrete areas including the main and accessory olfactory bulbs, the islands of Calleja, the amygdala, the paraventricular nucleus of the thalamus, several hypothalamic nuclei, the lateral geniculate nucleus, the magnocellular nucleus of the posterior commissure, the superior and inferior colliculi, the laterodorsal and pedunculopontine tegmental nuclei, the nucleus of the trapezoid body, the nucleus of the solitary tract and the cerebellum. Strongly-stained isolated neurons were scattered mainly in the cerebral cortex, the basal ganglia and the brain stem, especially the medulla reticular formation. In the hyppocampus, an almost uniform distribution of moderately stained neurons was observed in the granular cell layer of the dentate gyrus and in the pyramidal cell layer of the ammon's horn, while more intensely stained isolated neurons were scattered over the entire hippocampal region. These observations can serve as a good basis for studies on function and gene regulation of neuronal nitric oxide synthase.