Walch C, Schliebs R, Bigl V
Paul Flechsig Institute for Brain Research, Department of Neurochemistry, Karl Marx University, Leipzig, German Democratic Republic.
EXS. 1989;57:295-304. doi: 10.1007/978-3-0348-9138-7_29.
In order to evaluate the role of cholinergic cortical mechanisms in the shaping of visual cortical plasticity in more detail the present paper summarizes recent studies on the laminar distribution of muscarinic acetylcholine receptors, choline acetyltransferase, and sodium-dependent high-affinity choline uptake sites during postnatal ontogenesis of the visual cortex of monocularly derived rats using autoradiographic techniques as well as quantitative biochemical methods after separating the different cortical layers by a cryocut technique. The data are correlated to the laminar distribution of cholinergic fibers within the visual cortex as studied by the immunohistochemical visualization of choline acetyltransferase. The laminar distribution of cholinergic receptor binding in the visual cortex changes during ontogenesis. In adult rats, the highest muscarinic acetylcholine receptor density is found in layer I. The activity of the choline acetyltransferase is rather uniformly distributed in all cortical layers. Adult activity values are reached at the age of 25 days. In adult rats the enzyme activity is highest in layer V. In all visual cortical layers the highest 3H-hemicholinium-3 binding to choline uptake sites during the postnatal period studied is already detectable at the age of 10 days, then binding decreases sharply until day 25 at which age it nearly equals the value found in the adult brain. Binding sites exhibit highest density in layers I and IV of the adult rat visual cortex. Monocular deprivation resulted in significant changes in all three parameters studied with different cortical laminae preferentially affected. The data suggest that the normal laminar development of the modulatory function of cholinergic transmission in the rat visual cortex depends on the presence of physiological light stimulation.
为了更详细地评估胆碱能皮质机制在视觉皮质可塑性形成中的作用，本文总结了近期的研究，这些研究利用放射自显影技术以及在通过冷冻切片技术分离不同皮质层后采用定量生化方法，研究了单眼剥夺大鼠视觉皮质出生后个体发育过程中，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。这些数据与通过胆碱乙酰转移酶免疫组织化学可视化研究的视觉皮质内胆碱能纤维的层状分布相关。视觉皮质中胆碱能受体结合的层状分布在个体发育过程中发生变化。在成年大鼠中，I层毒蕈碱型乙酰胆碱受体密度最高。胆碱乙酰转移酶的活性在所有皮质层中分布较为均匀。在25日龄时达到成年活性值。在成年大鼠中，该酶活性在V层最高。在所研究的出生后时期，所有视觉皮质层中与胆碱摄取位点的最高3H-半胱氨酸-3结合在10日龄时已可检测到，然后结合急剧下降，直到25日龄，此时其值几乎等于成年大脑中的值。结合位点在成年大鼠视觉皮质的I层和IV层中密度最高。单眼剥夺导致所研究的所有三个参数发生显著变化，不同皮质层受到的影响尤为明显。数据表明，大鼠视觉皮质中胆碱能传递调节功能的正常层状发育取决于生理光刺激的存在。
