Riba-Bosch A, Pérez-Clausell J
Departament de Biologia Cel.lular, Universitat de Barcelona, Facultat de Biologia, Diagonal 645, ES-08071 Barcelona, Spain.
Neuroscience. 2004;125(3):803-18. doi: 10.1016/j.neuroscience.2004.02.017.
A pool of zinc is present in synaptic vesicles in a population of glutamatergic neurones. Zinc appears to modulate synaptic transmission and cause neuronal death. The status of vesicular zinc, neuronal death and glial reaction in the rat forebrain was analysed after a systemic injection of kainic acid in order to establish a model for future studies on zinc function. Rats received a systemic injection of kainic acid (10 mg/kg) and were killed 3, 6, 12, 24 and 48 h post-treatment. Timm's method and zinquin staining were used to detect zinc. Immunostaining for Fos-like proteins and staining with Fluoro-Jade B were used to detect cell reaction and degeneration, respectively. Glial fibrillary acidic protein and tomato lectin were used as glial markers. Zinquin staining for zinc rose transitorily in neuronal somata 6 h after injection (not observed at 24-48 h) in the piriform and entorhinal cortices, amygdala and hippocampus. In contrast sulphide/silver staining for zinc showed virtually no rise in cytoplasmic zinc (except in cornus ammonis field 1 of the hippocampus) 6 h after injection, and a decrease (bleaching) in some terminal fields starting 12 h after injection and increasing at 24-48 h. The areas most affected by the zinc bleaching were the olfactory bulb, piriform and entorhinal cortices, endopiriform and amygdaloid nuclei. Transitory Fos immunostaining (within neuronal nuclei) was observed between 3 and 12 h after kainate treatment in many telencephalic areas: olfactory bulb, cortex (piriform, hippocampal and neocortex) and amygdaloid nuclei. This was accompanied by changes in glial markers starting 3 h after injection. Fluoro-Jade B staining in neurones (degeneration) appeared 6 h after treatment and increased later. Degenerating areas generally coincided with those showing Fos immunoreactivity. Zinquin and sulphide/silver methods revealed various pools of zinc after kainate injection: a cytoplasmic pool and a terminal field (or vesicular) pool. Cytoplasmic zinc (zinquin) was coincident, in time and location, with cell degeneration, thus implicating zinc in cell death. This zinc may not have come from presynaptic stores, since no bleaching (sulphide/silver method) was observed 6 h after injection. Future experiments altering zinc pools (e.g. by chelating agents) may elucidate the function of zinc.
在一群谷氨酸能神经元的突触小泡中存在锌池。锌似乎可调节突触传递并导致神经元死亡。为了建立一个用于未来锌功能研究的模型，在对大鼠进行全身注射 kainic 酸后，分析了大鼠前脑的囊泡锌状态、神经元死亡和神经胶质反应。大鼠接受全身注射 kainic 酸（10mg/kg），并在治疗后 3、6、12、24 和 48 小时处死。采用 Timm 法和锌喹啉染色检测锌。分别使用 Fos 样蛋白免疫染色和 Fluoro-Jade B 染色检测细胞反应和变性。使用胶质纤维酸性蛋白和番茄凝集素作为神经胶质标记物。注射后 6 小时，在梨状皮质、内嗅皮质、杏仁核和海马体的神经元胞体中，锌喹啉染色显示锌短暂升高（在 24 - 48 小时未观察到）。相比之下硫化物/银染色显示，注射后 6 小时细胞质锌几乎没有升高（海马体的海马 Ammon 氏角 1 区除外），并且从注射后 12 小时开始，一些终末区域出现锌减少（褪色），并在 24 - 48 小时增加。受锌褪色影响最严重的区域是嗅球、梨状皮质和内嗅皮质、内梨状核和杏仁核。在 kainate 处理后 3 至 12 小时之间，在许多端脑区域观察到短暂的 Fos 免疫染色（在神经元核内）：嗅球、皮质（梨状、海马和新皮质）和杏仁核。这伴随着注射后 3 小时开始的神经胶质标记物变化。神经元中的 Fluoro-Jade B 染色（变性）在治疗后 6 小时出现并随后增加。变性区域通常与显示 Fos 免疫反应性的区域一致。锌喹啉和硫化物/银方法显示 kainate 注射后存在不同的锌池：细胞质池和终末区域（或囊泡）池。细胞质锌（锌喹啉）在时间和位置上与细胞变性一致，因此表明锌与细胞死亡有关。这种锌可能并非来自突触前储存，因为注射后 6 小时未观察到褪色（硫化物/银方法）。未来改变锌池的实验（例如通过螯合剂）可能会阐明锌的功能。
