NMDA spikes in basal dendrites of cortical pyramidal neurons
NMDA spikes in basal dendrites of cortical pyramidal neurons
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DOI：
10.1038/35005094
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发表时间：
2000-03-16
期刊：
影响因子：
64.8
通讯作者：
Schiller, Y
中科院分区：
文献类型：
--
作者：
Schiller, J;Major, G;Schiller, Y
基底树突是支配皮质锥体神经元的突触输入的主要靶点（1）。目前，人们对这些细树突中的信号处理知之甚少。在这里，我们表明，集群相邻的基础输入的共激活启动局部树突棘波，这导致了5.9 +/- 1.5 mV（峰值）和64.4 +/- 19.8 ms（半宽度）电缆过滤的电压变化在索马，放大体细胞的电压响应226 +/-46%。这些尖峰伴随着大的钙瞬变限制在激活的树突状节段。与传统的钠或钙尖峰不同，这些尖峰主要由NMDA（N-甲基-D-天冬氨酸）受体通道介导，其贡献了至少80%的总电荷。这些NMDA尖峰的离子机制可能允许“动态尖峰起始区”，设置由谷氨酸预绑定到NMDA受体，这反过来又取决于最近和正在进行的活动在皮层网络的空间分布。此外，NMDA尖峰可能作为一个强大的机制，通过诱导长期加强共同激活的相邻输入的皮层网络的修改。
Basal dendrites are a major target for synaptic inputs innervating cortical pyramidal neurons(1). At present little is known about signal processing in these fine dendrites. Here we show that coactivation of clustered neighbouring basal inputs initiated local dendritic spikes, which resulted in a 5.9 +/- 1.5 mV (peak) and 64.4 +/- 19.8 ms (half-width) cable-filtered voltage change at the soma that amplified the somatic voltage response by 226 +/- 46%. These spikes were accompanied by large calcium transients restricted to the activated dendritic segment. In contrast to conventional sodium or calcium spikes, these spikes were mediated mostly by NMDA (N-methyl-D-aspartate) receptor channels, which contributed at least 80% of the total charge. The ionic mechanism of these NMDA spikes may allow 'dynamic spike-initiation zones', set by the spatial distribution of glutamate pre-bound to NMDA receptors, which in turn would depend on recent and ongoing activity in the cortical network. In addition, NMDA spikes may serve as a powerful mechanism for modification of the cortical network by inducing long-term strengthening of co-activated neighbouring inputs.