Rapid, experience-dependent changes in levels of synaptic zinc in primary somatosensory cortex of the adult mouse
Rapid, experience-dependent changes in levels of synaptic zinc in primary somatosensory cortex of the adult mouse
复制标题
DOI：
10.1523/jneurosci.22-07-02617.2002
复制
发表时间：
2002-04-01
影响因子：
5.3
通讯作者：
Dyck, RH
中科院分区：
文献类型：
--
作者：
Brown, CE;Dyck, RH
电生理学研究已经证实，成人大脑皮层在感觉外周受到扰动后，会立即发生功能重组。这些活动依赖性的修饰被认为是通过对现有连接的突触强度的快速调节来介导的。最近的研究表明，突触锌通过其调节谷氨酸能神经传递的强大能力，参与了皮层可塑性的活动依赖机制，如长期增强和长期抑制。为了研究突触锌在皮层可塑性中的作用，我们在拔须后不同时间点观察了成年小鼠初级体感皮层轴突末端锌的桶状分布变化。正常成年小鼠第4层桶区锌染色表现为桶间间隔强染色，桶孔低染色。在去除一排须后3小时至1周内，拔须后桶孔的锌染色显著增加。随着存活时间的延长，锌染色水平逐渐下降，在去除须后2-3周恢复到正常水平。在被剥夺的桶孔中，锌染色水平的增加与胡须再生时的长度呈高度负相关。这些结果表明，新皮层突触锌的水平受到感官体验变化的快速调节，并表明锌可能参与了通常发生在皮层的瞬时可塑性变化。
Electrophysiological studies have established that the adult cerebral cortex undergoes immediate functional reorganizations after perturbations of the sensory periphery. These activity-dependent modifications are thought to be mediated via the rapid regulation of the synaptic strength of existing connections. Recent studies have implicated synaptic zinc as contributing to activity-dependent mechanisms of cortical plasticity, such as long-term potentiation and long-term depression, by virtue of its potent ability to modulate glutamatergic neurotransmission. To investigate the role of synaptic zinc in cortical plasticity, we examined changes in the barrel-specific distribution of zinc in axon terminals innervating the primary somatosensory cortex of adult mice at different time points after whisker plucking. In layer IV of normal adult mice, zinc staining in the barrel field was characterized by intense staining in inter-barrel septae and low levels of staining in barrel hollows. Within 3 hr, and up to 1 week after the removal of a row of whiskers, zinc staining increased significantly in barrel hollows corresponding to the plucked whiskers. With longer survival times, levels of zinc staining gradually declined in deprived barrel hollows, returning to normal levels by 2-3 weeks after whisker removal. Increased levels of zinc staining in deprived barrel hollows were highly, negatively correlated with the length of whiskers as they regrew. These results indicate that levels of synaptic zinc in the neocortex are rapidly regulated by changes in sensory experience and suggest that zinc may participate in the plastic changes that normally occur in the cortex on a moment-to-moment basis.