Nakic M, Mitrovic N, Sperk G, Schachner M
Department of Neurobiology, Swiss Federal Institute of Technology, Hönggerberg, Zürich, Switzerland.
J Neurosci Res. 1996 May 15;44(4):355-62. doi: 10.1002/(SICI)1097-4547(19960515)44:4<355::AID-JNR7>3.0.CO;2-B.
Kainic acid-induced limbic seizures enhance expression of tenascin-C (TN) in the hippocampus of adult rats. TN mRNA was detectable by in situ hybridization in many granule cells in the dentate gyrus 4.5 hr after kainic acid injection but not in saline-injected animals (controls) or in animals killed 2 or 24 hr after injection. Thirty days after kainic acid injection, TN mRNA was detectable only in pyramidal cells of CA3 and CA1. At the protein level, TN was detectable by immunocytochemistry in control animals in the strata oriens and lacunosum moleculare of CA1, in the molecular layer, and within a narrow area at the inner surface of the granule cell layer in the dentate gyrus. Twenty-four hours after kainic acid injection, TN immunoreactivity was enhanced in these areas and throughout the granule cell layer. Thirty days after kainic acid injection, TN immunoreactivity was downregulated in these areas, while it was prominent in the stratum oriens and in clusters of immunoreactivity in the stratum lucidum of CA3. Western blot analysis of the hippocampus showed a peak of TN expression 24 hr after kainic acid injection. These observations show that TN expression is upregulated in predominantly neuronal cells already by 4.5 hr after kainic acid injection, coincident with activation of granule cells and sprouting of axon terminals, whereas the remaining TN expression 30 days after injection relates to pyramidal cells in CA1 and CA3, coincident with an astroglial response, as marked by a strong expression of glial fibrillary acidic protein.
海藻酸诱导的边缘叶癫痫发作可增强成年大鼠海马中腱生蛋白-C（TN）的表达。在注射海藻酸4.5小时后，通过原位杂交可在齿状回的许多颗粒细胞中检测到TN mRNA，但在注射生理盐水的动物（对照组）或注射后2小时或24小时处死的动物中未检测到。注射海藻酸30天后，仅在CA3和CA1的锥体细胞中可检测到TN mRNA。在蛋白质水平上，通过免疫细胞化学在对照组动物的CA1的海马床层和分子层、分子层以及齿状回颗粒细胞层内表面的狭窄区域中可检测到TN。注射海藻酸24小时后，这些区域以及整个颗粒细胞层中的TN免疫反应性增强。注射海藻酸30天后，这些区域中的TN免疫反应性下调，而它在海马床层和CA3透明层中的免疫反应性簇中很突出。对海马进行蛋白质印迹分析显示，注射海藻酸24小时后TN表达达到峰值。这些观察结果表明，在注射海藻酸后4.5小时，主要在神经元细胞中TN表达上调，这与颗粒细胞的激活和轴突终末的出芽同时发生，而注射后30天剩余的TN表达与CA1和CA3中的锥体细胞有关，这与星形胶质细胞反应同时发生，如通过胶质纤维酸性蛋白的强烈表达所标记。
