Section of Psychiatry, Department of Clinical Neuroscience, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.
Brain Res. 2011 Feb 23;1375:1-6. doi: 10.1016/j.brainres.2010.11.085. Epub 2010 Dec 4.
Using pentylenetetrazol (PTZ) kindling, we collected hippocampal tissue from standard response and kindling resistant animals, measuring hippocampal mRNA with real-time PCR of glutamate transporters GLAST, GLT-1, and EAAC1 and the sodium-coupled neutral amino acid transporter (SNAT) 1, SNAT2, and SNAT3. In addition, we measured mRNA of glutamine synthetase (GS), phosphate-activated glutaminase (PAG), glutamic acid decarboxylase (GAD) 1, GAD2, and vesicular inhibitory amino acid transporter (VIAAT). Fully kindled animals had decreased expression of mRNA in the hippocampus for GLAST and GAD2 compared with saline injected control. mRNA for SNAT1, SNAT2, SNAT3, GS, and VIAAT was increased. After induction of generalized tonic-clonic seizures by PTZ there were no differences in mRNA at 24h after seizures, equaling baseline quantities except for GAD1, which was decreased. When levels were measured at 30days after a PTZ induced convulsive seizure, we found increased levels of GLT-1, SNAT1 and GS, but decreased levels of GAD1. When these animals, serving as control for the 30day interval between the last convulsive seizure in the kindled experimental group, were analyzed, we found that GLT-1, SNAT3, GAD1 and VIAAT differed in that GLT-1 was decreased and the others increased. Animals found resistant to kindling had strikingly different mRNA patterns, with markedly up-regulated mRNA of proteins that transport glutamate into neurons and glia; SNAT1 was up regulated as well. Up-regulation of genes in kindling resistant animals supports the hypothesis that clearance of glutamate, conversion to glutamine and transport of glutamine into neurons, has the effect of raising the threshold for convulsive seizures and attenuating kindling.
使用戊四氮（PTZ）点燃，我们从标准反应和点燃抗性动物中收集海马组织，使用实时 PCR 测量谷氨酸转运体 GLAST、GLT-1 和 EAAC1 以及钠偶联中性氨基酸转运体（SNAT）1、SNAT2 和 SNAT3 的海马 mRNA。此外，我们还测量了谷氨酰胺合成酶（GS）、磷酸激活谷氨酰胺酶（PAG）、谷氨酸脱羧酶（GAD）1、GAD2 和囊泡抑制性氨基酸转运体（VIAAT）的 mRNA。与盐水注射对照相比，完全点燃的动物的海马中 GLAST 和 GAD2 的 mRNA 表达降低。SNAT1、SNAT2、SNAT3、GS 和 VIAAT 的 mRNA 增加。在 PTZ 诱导全身性强直-阵挛性发作后，除 GAD1 减少外，发作后 24 小时的 mRNA 没有差异，与基线量相等。当在 PTZ 诱导的强直-阵挛性发作后 30 天测量水平时，我们发现 GLT-1、SNAT1 和 GS 的水平增加，但 GAD1 的水平降低。当这些动物作为点燃实验组最后一次强直-阵挛性发作后 30 天间隔的对照进行分析时，我们发现 GLT-1、SNAT3、GAD1 和 VIAAT 不同，GLT-1 降低，其他增加。对点燃具有抗性的动物具有明显不同的 mRNA 模式，表明将谷氨酸转运到神经元和神经胶质细胞的蛋白质的 mRNA 上调；SNAT1 也上调。点燃抗性动物中基因的上调支持这样的假设，即谷氨酸的清除、转化为谷氨酰胺以及谷氨酰胺向神经元的转运，具有提高惊厥发作阈值和减弱点燃的作用。
