Gap junctions among dendrites of cortical GABAergic neurons establish a dense and widespread intercolumnar network
Gap junctions among dendrites of cortical GABAergic neurons establish a dense and widespread intercolumnar network
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DOI：
10.1523/jneurosci.4076-05.2006
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发表时间：
2006-03-29
影响因子：
5.3
通讯作者：
Galuske, RAW
中科院分区：
文献类型：
--
作者：
Fukuda, T;Kosaka, T;Galuske, RAW
间隙连接在皮层gaba能中间神经元之间是常见的，但对其沿树突分布的数量知之甚少。在这里，我们提供了直接的形态学证据，表明猫视觉皮层第2/3层含有小蛋白的gaba能神经元通过树突间隙连接形成密集而广泛的网络。应用connexin36免疫组织化学和共聚焦激光扫描显微镜（CLSM）观察了小白蛋白神经元的间隙连接偶联网络。connexin36免疫阳性点和间隙连接的直接对应关系在CLSM和电镜检查中得到证实。具有大体细胞的单个小白蛋白神经元（>= 200 μ m(2)）与其他细胞形成60.3 +/- 12.2（平均+/- SD）的间隙连接，这些接触不仅限于近端树突，而且发生在距离体细胞380 μ m的距离上。在对大型小白蛋白神经元的shll分析中，21.9个+/- 7.9个间隙连接位于体细胞50 μ m以内，21.7个+/- 7.6个间隙连接位于50 - 100 μ m之间，11.2个+/- 4.7个连接位于100 - 150 μ m之间，5.6个+/- 3.6个连接位于更远的节段。串行连接的神经元可以通过多个间隙连接以无限的方式横向追踪。与取向偏好柱的比较表明，细小蛋白免疫反应细胞的分布是随机的，它们的大树突场重叠很大，覆盖了不同的取向柱。本文提出，这种密集和均匀的中间神经元电耦合支持具有不同特征偏好的神经元群体的精确同步，从而为分布式表征的生成提供了一个时间框架。
Gap junctions are common between cortical GABAergic interneurons but little is known about their quantitative distribution along dendritic profiles. Here, we provide direct morphological evidence that parvalbumin-containing GABAergic neurons in layer 2/3 of the cat visual cortex form dense and far-ranging networks through dendritic gap junctions. Gap junction- coupled networks of parvalbumin neurons were visualized using connexin36 immunohistochemistry and confocal laser-scanning microscopy (CLSM). The direct correspondence of connexin36-immunopositve puncta and gap junctions was confirmed by examining the same structures in both CLSM and electron microscopy. Single parvalbumin neurons with large somata (>= 200 mu m(2)) formed 60.3 +/- 12.2 (mean +/- SD) gap junctions with other cells whereby these contacts were not restricted to proximal dendrites but occurred at distances of up to 380 mu m from the soma. In a Sholl analysis of large-type parvalbumin neurons, 21.9 +/- 7.9 gap junctions were within 50 mu m of the soma, 21.7 +/- 7.6 gap junctions in a segment between 50 and 100 mu m, 11.2 +/- 4.7 junctions between 100 and 150 mu m, and 5.6 +/- 3.6 junctions were in more distal segments. Serially interconnected neurons could be traced laterally in a boundless manner through multiple gap junctions. Comparison to the orientation-preference columns revealed that parvalbumin-immunoreactive cells distribute randomly whereby their large dendritic fields overlap considerably and cover different orientation columns. It is proposed that this dense and homogeneous electrical coupling of interneurons supports the precise synchronization of neuronal populations with differing feature preferences thereby providing a temporal frame for the generation of distributed representations.