Bailly Y J, Schoen S W, Mariani J, Kreutzberg G W, Delhaye-Bouchaud N
Laboratoire de Neurobiologie du Développement, Institut des Neurosciences (URA 1488), CNRS et Université Pierre et Marie Curie, Paris, France.
Synapse. 1998 Jul;29(3):279-92. doi: 10.1002/(SICI)1098-2396(199807)29:3<279::AID-SYN11>3.0.CO;2-O.
During postnatal development of the rodent cerebellum, a transient enzyme activity of ecto-5'-nucleotidase has been shown in the asymmetrical synapses of Purkinje cells. The alterations of the afferent circuitry and microenvironment of the ectopic Purkinje cells present in the cerebellum of the reeler mutant mouse could enlighten parameters that influence the synaptic 5'-nucleotidase activity of these cells. Ecto-enzyme cytochemistry reveals intense 5'-nucleotidase activity in 43% of synapses of the Purkinje cells throughout the cortex and the core of the reeler cerebellar vermis, although the molecular layer displays large areas with less than 1% of labelled synapses. However, enzymatic labelling is found in considerably more Purkinje cells synapses (73%) throughout the granular layer and the subcortical mass. Climbing fiber synapses of monoinnervated Purkinje cells are labelled by 5'-nucleotidase activity in the molecular layer, as well as asymmetrical synapses made on the subjacent ectopic Purkinje cells by the multiple climbing fibers and by the heterologous afferences. The non-innervated dendritic spines of these cells are also labelled, suggesting that 5'-nucleotidase activity at postsynaptic sites of reeler Purkinje cells does not depend on the presynaptic innervation. Rather, 5'-nucleotidase enzyme activity is enhanced at theses sites when the Purkinje cells have not achieved chemodifferentiation but have conserved immature wiring, i.e., low parallel fiber and multiple climbing fiber inputs.
在啮齿动物小脑的出生后发育过程中，已在浦肯野细胞的不对称突触中发现了ecto-5'-核苷酸酶的瞬时酶活性。reeler突变小鼠小脑中异位浦肯野细胞的传入神经回路和微环境的改变，可能会揭示影响这些细胞突触5'-核苷酸酶活性的参数。外切酶细胞化学显示，在整个reeler小脑蚓部的皮质和核心区域，43%的浦肯野细胞突触中有强烈的5'-核苷酸酶活性，尽管分子层中大片区域的标记突触少于1%。然而，在颗粒层和皮质下区域的更多浦肯野细胞突触（73%）中发现了酶标记。单突触浦肯野细胞的攀缘纤维突触在分子层中被5'-核苷酸酶活性标记，以及由多条攀缘纤维和异源传入神经在相邻异位浦肯野细胞上形成的不对称突触也被标记。这些细胞未受神经支配的树突棘也被标记，这表明reeler浦肯野细胞突触后位点的5'-核苷酸酶活性不依赖于突触前神经支配。相反，当浦肯野细胞尚未实现化学分化但保留了不成熟的神经连接，即低平行纤维和多条攀缘纤维输入时，这些位点的5'-核苷酸酶活性会增强。
