AMPA receptor and its role in astroglia

我们从胚胎大鼠大脑皮层制备了富含星形胶质细胞的培养物，并利用钙显像技术研究了星形胶质细胞中AMPA受体的激活情况。在我们的培养条件下，在一小部分细胞中观察到AMPA受体引起的细胞内钙浓度的增加。这种钙反应被PEPA和环噻嗪增强，AMPA受体的变构增强剂，两种药物的增强程度取决于细胞。这可能是由于AMPA受体的细胞依赖性异质性。在这些细胞中，用膜片钳记录AMPA受体介导的膜电流。目前的反应也被PEPA增强，并显示出内向整流的I-V关系，至少在我们测试的细胞中是这样。我们已经检查了神经胶质AMPA受体激活刺激的基因表达。为此，对胶质细胞培养的mRNA进行了定量RT-PCR。在我们的培养中，我们没有发现GDNF mRNA表达水平的显著增加。我们进一步研究了其他基因，并从其他脑区制备了神经胶质细胞，以期获得更多关于神经胶质AMPA受体的信息。

We have prepared astroglia-rich cultures from the embryonic rat cerebral cortex, and investigated activation of AMPA receptor in astroglia using calcium-imaging. In our culture condition, AMPA receptor-evoked increases in intracellular calcium concentration was observed in a small population of cells. This calcium responses were potentiated by PEPA and cyclothiazide, allosteric potentiators of AMPA receptors, and the extent of potentiation by two drugs depends upon cells. This is probably due to cell-dependent heterogeneity of AMPA receptors. In these cells, membrane currents mediated by AMPA receptors were recorded using patch clamp recordings.The current responses were also potentiated by PEPA, and show inwardly rectifying I-V relation, at least in the cells we tested. We have examined gene expression stimulated by the activation of glial AMPA receptors. For this purpose, quantitative RT-PCR was carried out for mRNA from glial cultures. We could not detect significant increases in expression of GDNF mRNA level in our cultures. We have further investigated on other gene, and prepared glial cells from other brain regions, in order to get further information on glial AMPA receptors.