Gottlieb M, Matute C
Departamento de Neurociencias, Universidad del País Vasco, Vizcaya, Spain.
J Cereb Blood Flow Metab. 1997 Mar;17(3):290-300. doi: 10.1097/00004647-199703000-00006.
We examined by immunohistochemistry the expression of ionotropic glutamate receptor subunits (GluRs) in glial cells of the rat dorsal hippocampus 3 to 28 days after transient forebrain ischemia. In general, the expression of GluRs at all time points studied underwent a drastic reduction that was primarily restricted to the CA1 region. In addition to the disappearance of GluRs as a result of neuronal cell death, we observed their expression in reactive glial cells. The time course of expression and the subunits involved were different for astrocytes and microglia. Reactive astrocytes exhibited kainate, GluR5-7, and N-methyl-D-aspartate (NMDA), NR2A/B, receptor subunits, both of which were maximally expressed approximately 4 weeks after ischemia. In contrast, reactive microglia expressed GluR4 and NR1 subunits, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and NMDA receptor subtypes, respectively, with maximal expression observed between 3 and 7 days after ischemia. These results demonstrate that specific types of GluRs are expressed in reactive glial cells after ischemia and that, overall, their expression levels peak around or after the periods of maximal astrogliosis and microgliosis. Thus, modulation of GluR expression may be one of the molecular components accompanying the gliotic process.
我们通过免疫组织化学方法检测了短暂性前脑缺血后3至28天大鼠背侧海马神经胶质细胞中离子型谷氨酸受体亚基（GluRs）的表达。总体而言，在所研究的所有时间点，GluRs的表达都大幅降低，且主要局限于CA1区。除了由于神经元细胞死亡导致GluRs消失外，我们还观察到它们在反应性神经胶质细胞中的表达。星形胶质细胞和小胶质细胞的表达时间进程及所涉及的亚基有所不同。反应性星形胶质细胞表现出海藻酸、GluR5 - 7以及N - 甲基 - D - 天冬氨酸（NMDA）、NR2A/B受体亚基的表达，两者在缺血后约4周时表达量最高。相比之下，反应性小胶质细胞分别表达GluR4和NR1亚基、α - 氨基 - 3 - 羟基 - 5 - 甲基 - 4 - 异恶唑丙酸（AMPA）和NMDA受体亚型，在缺血后3至7天观察到表达量最高。这些结果表明，缺血后特定类型的GluRs在反应性神经胶质细胞中表达，并且总体而言，它们的表达水平在星形胶质细胞增生和小胶质细胞增生的高峰期或之后达到峰值。因此，GluR表达的调节可能是胶质化过程伴随的分子组成部分之一。
