出生前后胆碱乙酰转移酶在大鼠脑内定位的研究

Localization of choline aceyltransferase during ante partum and postnatal development in the rat brain

为探讨大鼠胚胎及生后发育期间脑内胆碱乙酰转移酶(choline acetyltransferase,ChAT)的变化规律,本研究采用免疫组织化学方法,观察了胚胎和生后大鼠脑内ChAT样(ChAT-like immunoreactive,ChAT-LI)神经元表达的数量和灰度值。结果显示:ChAT-LI产物主要表达在细胞体、纤维及其末梢。ChAT-LI神经元最先在胚胎第12d(embryonic day12,E12),出现于端脑;E14时可见于隔核和中缝核;E16时内嗅区出现ChAT-LI神经元;E18时出现于视前区节细胞层;E20时,海马内部可见部分ChAT-LI纤维;生后第0d(postnatal day0,P0),少量带有生长锥的ChAT-LI纤维出现于海马;P5时,海马内出现ChAT-LI神经元,且ChAT-LI纤维进一步增加;P10时,海马、内嗅区和穹隆等结构中都可见ChAT-LI神经元胞体及纤维。上述结果提示:胆碱能神经元在出生前后的大鼠脑内,尤其是在海马记忆回路的发育过程中存在一定的变化规律,它们可能是学习记忆等功能的结构基础。

To study the distribution of choline acetyhranoferase （CHAT） in the brain during ante partum and postnatal development, we used immunohistochemi and image processing techniques to observe and analyze the quantity and optical density of cholinergic neurons in several structures of the brain. The results showed that ChAT-fike immunoreactive （-LI） structures were mainly distributed in the cholinergic neurons, mostly in the cell bodies, fibers, and terminals. During the embryonic development, cholinergic cells firstly appeared in telencephalon at embryonic day 12 （El2）, raphe nuclei and septal nuclei at El4, entol＂hinal mea at El6, ganglion cell layer of preoptic region at El8 ,respectively. However, ChAT-LI fibers appeared in the hippocampus around E20. At postnatal day 0 （PO） , a few unbranched ChAT-LI fibers, capped with growth cones, were already visible in the hippocampus. At P5, a few faint ChAT-LI neurons appcared in the hippocampus with increasing positive fibers. At P10, neurons and fibers in the hippocampus, entorhinsl area, fornix shewed strong positive staining. The present results suggested that there are certain temporal regularity of the appearance of cholinergic neuron in the brain, especially in the hippocampus memory circuit during development, which might be related to the development of learning and memory function in the nervous system.