Ong W Y, Garey L J, Tan K K
Department of Anatomy, National University of Singapore, Singapore.
Exp Brain Res. 1997 Jan;113(1):117-29. doi: 10.1007/BF02454147.
The distributions of the kainate/DL-alpha-amino-3-hydroxy-5-methylisoxazolepropionic acid (KA/ AMPA) receptors GluR1 and calcium-activated neutral protease II (calpain II) in the hippocampus of normal and kainate-lesioned rats were studied by immunocytochemistry. There was a reduction in GluR1 immunoreactivity and a slight increase in calpain II immunoreactivity on the dendrites of pyramidal neurons in CA fields affected by the kainate at 18 h postinjection. Calpain II immunore-activity was associated with amyloid fibrils at electron microscopy. These fibrils were most often intracellular, in membrane-bound profiles, some of which were contacted by axon terminals and were identified as degenerating dendrites. There was extensive destruction of mitochondrial membranes in degenerating profiles, and accumulations of amyloid fibrils were often localised in mitochondria in a calpain-positive profile. This was unlike other, calpain-negative degenerating profiles, that contained tubulovesicular profiles or multilamellar bodies, where mitochondrial membranes were preserved. Many more calpain-positive profiles were observed at electron microscopy 6 days after kainate injection. The enzyme was present in macrophages and astrocytes in lesioned areas.
通过免疫细胞化学方法研究了正常大鼠和经红藻氨酸损伤的大鼠海马中红藻氨酸/α-氨基-3-羟基-5-甲基异恶唑丙酸（KA/AMPA）受体GluR1和钙激活中性蛋白酶II（钙蛋白酶II）的分布情况。注射红藻氨酸18小时后，在受红藻氨酸影响的CA区锥体神经元树突上，GluR1免疫反应性降低，钙蛋白酶II免疫反应性略有增加。在电子显微镜下，钙蛋白酶II免疫反应性与淀粉样纤维有关。这些纤维最常位于细胞内，呈膜结合形态，其中一些与轴突终末接触，并被鉴定为退化的树突。在退化形态中，线粒体膜遭到广泛破坏，淀粉样纤维聚积物常常定位于钙蛋白酶阳性形态的线粒体中。这与其他不含微管泡状结构或多层小体的钙蛋白酶阴性退化形态不同，后者的线粒体膜是完整的。在注射红藻氨酸6天后的电子显微镜观察中，发现了更多的钙蛋白酶阳性形态。该酶存在于损伤区域的巨噬细胞和星形胶质细胞中。
