Structural changes at synapses after delayed perfusion fixation in different regions of the mouse brain
Structural changes at synapses after delayed perfusion fixation in different regions of the mouse brain
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DOI：
10.1002/cne.21276
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发表时间：
2007-04-10
影响因子：
2.5
通讯作者：
Reese, Thomas S.
中科院分区：
文献类型：
--
作者：
Tao-Cheng, Jung-Hwa;Gallant, Paul E.;Reese, Thomas S.
我们最近在电子显微镜下发现，在类缺血条件下，来自海马区培养的突触后密度(PSD)经历了快速的结构变化。在这里，我们报告了类似的结构变化发生在延迟后，经心脏灌流固定小鼠的大脑。延迟灌流固定，一种模拟缺血应激的情况，导致来自海马区(CA1)、大脑皮层(III层)和小脑皮层(浦肯野棘区)的PSD的厚度分别增加70%、90%和23%。随着PSD的增厚，大脑皮质脊椎中PSD相关的(α-钙钙调素依赖的蛋白激酶II，α-CaMKII)标记的数量比浦肯野棘中增加得更多。虽然延迟固定后Purkinje PSD仅有轻微增厚，但它们变得高度弯曲，许多形成直径类似于80 nm的亚PSD球，标记为CaMKII。延迟灌流固定还可在锥体细胞胞体内产生更多的CaMKII胞浆(直径约110 nm)，而浦肯野细胞胞浆中CaMKII胞浆胞团直径较小。因此，短暂的灌注固定延迟会在PSD和神经元SoMas产生细胞特有的结构变化。浦肯野细胞对延迟灌流固定的反应略有不同，可能是由于它们在PSD上CaMKII和CaMKII结合蛋白的水平较低。我们在这里提出了一系列的结构变化，这些变化标志着灌注固定延迟，从而提供了在实验性脑结构研究中评估灌注固定质量的标准，并阐明了代谢应激后在完整脑中发生的细微变化。
We recently showed by electron microscopy that the postsynaptic density (PSD) from hippocampal cultures undergoes rapid structural changes after ischemia-like conditions. Here we report that similar structural changes occur after delay in transcardial perfusion fixation of the mouse brain. Delay in perfusion fixation, a condition that mimics ischemic stress, resulted in 70%, 90%, and 23% increases in the thickness of PSDs from the hippocampus (CA1), cerebral cortex (layer III), and cerebellar cortex (Purkinje spines), respectively. In step with PSD thickening, the amount of PSD-associated (alpha-calcium calmodulin-dependent protein kinase II (alpha- CaMKII) label increased more in cerebral cortical spines than in Purkinje spines. Although the Purkinje PSDs thickened only slightly after delayed fixation, they became highly curved, and many formed sub-PSD spheres similar to 80 nm in diameter that labeled for CaMKII. Delayed perfusion fixation also produced more cytoplamic CaMKII clusters (similar to 110 nm in diameter) in the somas of pyramidal cells (from hippocampus and cerebral cortex) than in Purkinje cells. Thus a short delay in perfusion fixation produces cell-specific structural changes at PSDs and neuronal somas. Purkinje cells respond somewhat differently to delayed perfusion fixation, perhaps owing to their lower levels of CaMKII, and CaMKII binding proteins at PSDs. We present here a catalogue of structural changes that signal a perfusion fixation delay, thereby providing criteria by which to assess perfusion fixation quality in experimental structural studies of brain and to shed light on the subtle changes that occur in intact brain following metabolic stress.