一氧化氮合酶神经元在大鼠下丘脑中的分布观察

目的：观察大鼠下丘脑各核团内一氧化氮合酶（NOS）阳性神经元的形态及分布特征。方法：用黄递酶组织化学染色方法观测NOS神经元在大鼠下丘脑各核团中的分布。结果：视上核、室旁核内密集的NOS阳性神经元为大细胞型神经分泌神经元；其他核团内的阳性神经元主要为小细胞型神经分泌神经元，其中弓状核最密集，视前内侧核、Broca斜带核水平支次之，视前室周核、视前腹前核和视前外侧区内的密度最低。第三脑室室管膜上皮下见一些NOS阳性“触液神经元”，其胞体或突起伸向室管膜上皮，甚至嵌入其中。在弓状核、视前内侧束内有密集的NOS阳性神经纤维。结论：下丘脑各核团内NOS神经元的分布有差异。NO在下丘脑神经内分泌调节系统中起重要作用。

The Distribution of NOS-Positive Neurons in the Rat Hypothalamus

Objective:To study the morphology and distribution of neurons containing nitric oxide synthase (NOS)in the hypothalamic nucleus of the rat. Methods:NADPH diaphorase histochemistry method was used to investigate the distribution of NOS positive neurons in the hypothalamic nucleus of the rat. Results:In the paraventricular nucleus and supraoptic nucleus the NOS positive neurons were magnocellular neurosecretory type; and in others nucleus were microcellular neuroscretory type. The arcuate nucleus, the medical preoptic nucleus and nucleus horizontal limb diagonal band, the periventricular preoptic nucleus, anteroventral preoptic nucleus, lateral preoptic area were in descending order of the density of NOS. Beneath the ependymal cells of the third ventricle, NOS positive cerebrospinal fluid contacting neurons were founded, their cell bodies and dendrites extended toward the apendyma or even ingress into the ependymal cells. The density of NOS positive fibers also could be seen in the arcuate nucleus and medial forebrain bundle. Conclusion:The distribution of NOS neurons in the hypothalamic nucleus is different from each other. NO plays an important role in the regulation of the hypothalamic neuroendocrine system.