Endogenous zinc can be a modulator of glycinergic signaling pathway in the rat retina
Endogenous zinc can be a modulator of glycinergic signaling pathway in the rat retina
复制标题
DOI：
10.1007/s10735-005-1693-4
复制
发表时间：
2005-03
影响因子：
3.2
通讯作者：
M. Kaneda;K. Ishii;T. Akagi;T. Tatsukawa;T. Hashikawa
中科院分区：
文献类型：
--
作者：
M. Kaneda;K. Ishii;T. Akagi;T. Tatsukawa;T. Hashikawa
锌是海马体中海马能输入的调节剂。然而，在视网膜中，我们以前报道，内源性锌是存在于非谷氨酸能神经过程和早期的电生理研究表明，锌是抑制性信号通路，这是由甘氨酸和GABA介导的调制器。所有II无长突细胞，一个亚群的甘氨酸能无长突细胞，被确定为小白蛋白在大鼠视网膜的选择性免疫反应。因此，在本研究中，我们专注于是否锌是目前在AII无长突细胞使用银扩增结合免疫组织化学在大鼠视网膜。用膜片钳技术观察了锌对大鼠视网膜甘氨酸反应的影响。在超微结构水平上观察到银沉淀物与小清蛋白免疫反应性神经突起的关联。我们还发现，锌存在于神经过程，而不是小白蛋白免疫反应。当Zn ~（2+）浓度低于10 μM时，甘氨酸诱导的反应增强，但当Zn ~（2+）浓度大于50 μM时，甘氨酸诱导的反应受到抑制。我们的研究结果表明，视网膜神经元的神经过程中的锌调节抑制性信号通路，特别是在AII无长突细胞的甘氨酸受体介导的。
Zinc is a modulator of glutamatergic inputs in the hippocampus. In the retina, however, we previously reported that endogenous zinc is present in the non-glutamatergic neural processes and earlier electrophysiological studies suggest that zinc is a modulator of inhibitory signaling pathways, which are mediated by glycine and GABA. AII amacrine cells, a subpopulation of glycinergic amacrine cells, are identified by selective immunoreactivity for parvalbumin in the rat retina. In the present study, therefore, we focused on whether zinc is present in AII amacrine cells using silver amplification combined with immunohistochemistry in the rat retina. We also examined whether zinc modulate glycine response in the rat retina by the patch clamp technique. Association of silver precipitates with the parvalbumin-immunoreactive neural processes was observed at the ultrastructural level. We also found that zinc existed in the neural processes which were not parvalbumin-immunoreactive. Glycine-induced responses were augmented when the concentration of Zn2+was below 10 μM, but inhibited at Zn2+concentrations of 50 μM or more. Our results suggest the notion that zinc in neural processes of retinal neurons modulates the inhibitory signaling pathway, particularly that mediated by glycine receptors in AII amacrine cells.