Nacimiento W, Kreutzberg G W
Max-Planck-Institute for Psychiatry, Department of Neuromorphology, Martinsried, Federal Republic of Germany.
Exp Neurol. 1990 Sep;109(3):362-73. doi: 10.1016/s0014-4886(05)80028-7.
5'-Nucleotidase, a prominent nucleoside-producing ectoenzyme of glial plasma membranes, was studied by enzyme cytochemistry in the superior cervical ganglion of the rat under normal conditions and after pre- and postganglionic axotomy. In normal ganglia 5'-nucleotidase was restricted to capillary endothelial cells, localized both on the luminal surface and in pinocytotic vesicles. Following preganglionic axotomy, the number of enzyme-positive endothelial vesicles increased, whereas no 5'-nucleotidase was found on reactive Schwann cells during phagocytosis of degenerating preganglionic axon terminals. After postganglionic axotomy an even stronger increase in enzyme-containing endothelial vesicles occurred. In addition, 5'-nucleotidase activity became detectable on the plasma membrane of Schwann cells and proliferating satellite cells, which participate in the detachment of synapses from axotomized neurons. Fibroblasts in the endoneuronal connective tissue of regenerating ganglia also exhibited 5'-nucleotidase on their surface. The results obtained suggest that 5'-nucleotidase may be related to specific metabolic requirements of Schwann and satellite cells during regeneration and that these requirements differ from those of reactive Schwann cells after denervation of the ganglion. Postoperative changes in 5'-nucleotidase activity on endothelial cells and fibroblasts of the ganglion indicate an involvement of these cells in metabolic response elicited by pre- or postganglionic axotomy.
5'-核苷酸酶是神经胶质细胞质膜上一种重要的产生核苷的胞外酶，本研究采用酶细胞化学方法，在正常条件下以及节前和节后轴突切断后，对大鼠颈上神经节中的该酶进行了研究。在正常神经节中，5'-核苷酸酶仅限于毛细血管内皮细胞，定位于管腔表面和吞饮小泡中。节前轴突切断后，酶阳性内皮小泡的数量增加，而在吞噬变性节前轴突终末的过程中，未发现反应性雪旺细胞上有5'-核苷酸酶。节后轴突切断后，含酶内皮小泡的增加更为明显。此外，在雪旺细胞和增殖的卫星细胞的质膜上可检测到5'-核苷酸酶活性，这些细胞参与了轴突切断的神经元突触的脱离。再生神经节神经内膜结缔组织中的成纤维细胞表面也表现出5'-核苷酸酶活性。所得结果表明，5'-核苷酸酶可能与再生过程中雪旺细胞和卫星细胞的特定代谢需求有关，且这些需求与神经节去神经支配后反应性雪旺细胞的需求不同。神经节内皮细胞和成纤维细胞上5'-核苷酸酶活性的术后变化表明，这些细胞参与了节前或节后轴突切断引发的代谢反应。
