大鼠孤束核内NT-LI成分生后发育和衰老变化的光镜和电镜观察

用免疫细胞化学和电镜相结合技术,在光镜和电镜水平对生后4天、15天、30天、90天、300天和760天6组大鼠孤束核内神经降压肽样免疫反应(NT-LI)成分的生后发育和衰老变化进行了定量研究。光镜下孤束核内NT-LI胞体和终末主要分布于最后区平面,多见于背侧亚核、内侧亚核和连合核内。电镜下内侧亚核内可见NT-LI胞体、树突、轴突及终末。6组大鼠孤束核内NT-LI细胞均数和内侧亚核内NT-LI终末密度及其突触密度均以生后4天至15天间增长最快,NT-LI细胞数在生后15天达到最高,NT-LI终末及突触密度在生后90天达到最高。三者在生后300天时均明显减少。发育期内侧亚核内NT-LI终末构成的突触以Gray Ⅰ型为主,至老年期则变为Gray Ⅱ型占优势。发育期内侧亚核内以含清亮囊泡伴颗粒囊泡的NT-LI终末为主,老年期此类终末明显减少。只含清亮囊泡的NT-LI终末从生后至老年变化不明显。

A LIGHT AND ELECTRON MICROSCOPIC OBSERVATION OF THE POSTNATAL ONTOGENY AND AGING CHANGES OF NT-LI COMPONENTS IN THE NUCLEUS OF SOLITARY TRACT OF THE RAT

The ontogenic and aging changes of neurotensin-like immunoreactive (NT-LI) components in the nuclei of solitary tract (Sol) of six groups of rats of postnatal day 4, 15, 30, 90, 300, 760 were studied quantitively by the immunocytochemical method combined with the electron microscopy, the NT-LI ceils and terminals in the Sol were predominantly distributed at the area postrema level, most of which were observed in the dorsal subnucleus, medial subnueleus (SolM) and commissural nucleus. Under the electron microscope, NT-LI substance was found in perikarya, dendrites, axons and axon terminals. The density of NT-LI terminals and that of synapses which NT-LI terminals formed in the SolM increased as remarkably as the mean of NT-LI cell number in the Sol from postnatal day 4 to 15,but NT-LI cell number reached its maximum at postnatal day 15 and NT-LI terminals and synapses at postnatal day 90. All of these decreased obviously at postnatal day 300. The number of Gray type Ⅰ synapses which NT-LI terminals formd was much more than that of Gray type Ⅱ synapses during developing stage and the proportion of the latter was large during aging stage. The number of the NT-LI terminals with clear vesicles and granular ones was much more during developing stage and declined during aging stage. The number of the NT-LI terminals with clear vesicles only didn't change remarkably form postnatal. 4 to old age. Our results indicated that NT-LI components showed remarkable changes after birth in the Sol.