Horton H L, Levitt P
Department of Anatomy, Medical College of Pennsylvania, Philadelphia 19129.
J Neurosci. 1988 Dec;8(12):4653-61. doi: 10.1523/JNEUROSCI.08-12-04653.1988.
The limbic system-associated membrane protein (LAMP) is a 64 kDa protein that, in the adult brain, is present in cortical and subcortical regions comprising the limbic system (Levitt, 1984). The developmental expression of LAMP was studied in fetal rat brains to determine the specific patterns of distribution and the cellular elements that exhibit LAMP immunoreactivity. Light microscopic immunocytochemical analysis revealed that LAMP is expressed on neurons and their growing axons early in fetal development, at a time coincident with pathway formation and differentiation of limbic system nuclei. In the forebrain, where limbic system structures are heavily concentrated, immunoreactivity appears on subpopulations of axons in a temporal sequence that correlates with the time of formation of pathways carrying limbic system axons. Thus, staining is evident first at embryonic day (E) 15 on fibers within the internal capsule coursing from the diencephalon to cortex. LAMP immunoreactivity appears over the next 3 d in the anterior commissure, fornix, and corpus callosum. Ultrastructural immunocytochemical analysis reveals dense surface staining of fascicles of developing axons and growth cones. The axonal staining is transient, disappearing during the second postnatal week of development. In cerebral cortex, cells in presumptive limbic cortical regions such as lateral perirhinal sulcal cortex and prefrontal cortex are LAMP immunoreactive from the inception of the cortical plate. These cortical regions are clearly delineated from surrounding unstained nonlimbic areas as early as E15. Thus, LAMP expression in the cortex may represent one of the earliest markers of specific cytoarchitectonic areas.(ABSTRACT TRUNCATED AT 250 WORDS)
边缘系统相关膜蛋白（LAMP）是一种64 kDa的蛋白质，在成人大脑中，存在于构成边缘系统的皮质和皮质下区域（莱维特，1984年）。研究了胎鼠脑中LAMP的发育表达，以确定其特定的分布模式以及表现出LAMP免疫反应性的细胞成分。光学显微镜免疫细胞化学分析显示，LAMP在胎儿发育早期就在神经元及其生长的轴突上表达，这一时期与边缘系统核团的通路形成和分化同时发生。在前脑，边缘系统结构高度集中，免疫反应性按时间顺序出现在轴突亚群上，这与携带边缘系统轴突的通路形成时间相关。因此，在胚胎第15天（E15），从间脑延伸至皮质的内囊纤维上首先出现染色。在接下来的3天里，前连合、穹窿和胼胝体出现LAMP免疫反应性。超微结构免疫细胞化学分析显示，发育中的轴突束和生长锥表面有密集染色。轴突染色是短暂的，在出生后第二周发育过程中消失。在大脑皮质，从皮质板形成开始，假定的边缘皮质区域如外侧嗅周沟皮质和前额叶皮质中的细胞就具有LAMP免疫反应性。早在E15时，这些皮质区域就与周围未染色的非边缘区域明显区分开来。因此，皮质中LAMP的表达可能代表特定细胞构筑区域的最早标志物之一。（摘要截短于250字）
