Walch C, Schliebs R
Paul Flechsig Institute for Brain Research, Department of Neurochemistry, Karl Marx University, Leipzig, G.D.R.
Neurochem Int. 1989;14(3):337-46. doi: 10.1016/0197-0186(89)90060-0.
The laminar distribution of muscarinic acetylcholine receptors, choline acetyltransferase, and sodium-dependent high-affinity choline uptake sites was studied in individual layers of rat visual cortex at 10, 15, 25 and 90 days of age, using a cryocut technique to separate the different cortical layers. Muscarinic acetylcholine receptor density in layer I rises sharply from postnatal day 10 to day 25, and then it continues to increase more gradually until adulthood. In layers II-V, receptor density increases slightly from day 10 to day 15, then it rises sharply until day 25 and continues decreasing up to day 90. In layer VI, muscarinic receptor binding increases markedly from postnatal day 10 to day 25, at which age the adult level is reached. Only slight developmental changes in the dissociation constants were observed in layers I-VI. The activity of the choline acetyltransferase rises in all cortical layers slightly from day 10 to day 15 followed by a sharp increase until day 25, at which age already the adult activity level is reached. In all visual cortical layers, the highest [(3)H]hemicholinium-3 binding to choline uptake sites during the postnatal period studied is already detectable at 10 days of age, then binding decreases sharply until day 25 at which age it nearly equals the value found in the adult. No essential developmental changes in the laminar pattern of choline acetyltransferase activity and choline uptake sites in rat visual cortex are observed, whereas the laminar distribution of muscarinic acetylcholine receptor density at 25 days of age is significantly different to that detectable in adulthood. The developmental changes in the laminar pattern of muscarinic receptors which represent the target structures that receive cholinergic input, might reflect changes of the cholinergic activity in the visual cortical layers during postnatal development.
利用冷冻切片技术分离大鼠视皮层的不同层，研究了10、15、25和90日龄大鼠视皮层各层中毒蕈碱型乙酰胆碱受体、胆碱乙酰转移酶和钠依赖性高亲和力胆碱摄取位点的层状分布。I层中毒蕈碱型乙酰胆碱受体密度从出生后第10天到第25天急剧上升，然后继续逐渐增加直至成年。在II - V层中，受体密度从第10天到第15天略有增加，然后急剧上升直至第25天，并持续下降至第90天。在VI层中，毒蕈碱受体结合从出生后第10天到第25天显著增加，在该年龄达到成年水平。在I - VI层中仅观察到解离常数的轻微发育变化。胆碱乙酰转移酶的活性在所有皮层层中从第10天到第15天略有上升，随后急剧增加直至第25天，在该年龄已达到成年活性水平。在所有视皮层层中，在所研究的出生后时期，与胆碱摄取位点的最高[³H]半胱氨酸-3结合在10日龄时就已可检测到，然后结合急剧下降直至第25天，在该年龄其几乎等于成年时的值。未观察到大鼠视皮层中胆碱乙酰转移酶活性和胆碱摄取位点的层状模式有本质的发育变化，而25日龄时毒蕈碱型乙酰胆碱受体密度的层状分布与成年时可检测到的分布显著不同。作为接受胆碱能输入的靶结构的毒蕈碱受体层状模式的发育变化，可能反映了出生后发育过程中视皮层层中胆碱能活性的变化。
