Functional thalamocortical synapse reorganization from subplate to layer IV during postnatal development in the reeler-like mutant rat (Shaking rat Kawasaki)
Functional thalamocortical synapse reorganization from subplate to layer IV during postnatal development in the reeler-like mutant rat (Shaking rat Kawasaki)
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DOI：
10.1523/jneurosci.4023-04.2005
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发表时间：
2005-02-09
影响因子：
5.3
通讯作者：
Molnár, Z
中科院分区：
文献类型：
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作者：
Higashi, S;Hioki, K;Molnár, Z
丘脑轴突和亚板神经元之间的瞬时突触形成被认为在丘脑皮质靶向中很重要。川崎震动大鼠 (SRK) 逆转了在卷轴小鼠中观察到的皮质分层，提供了一个有趣的模型系统来测试这一想法。在 SRK 丘脑皮质切片制剂中使用电压敏感染料进行光学记录，研究了激发的空间和时间模式。出生后第 0 天 (P0)，在对应于野生型 (WT) 大鼠亚板的细胞层中 SRK 超板内引发了强烈的光学反应。到 P3 时，这种反应迅速下降到由 IV 层细胞组成的深层皮质层，如胚胎第 17 天的 5-溴-2'-脱氧尿苷生日鉴定。在出生后的前 3 天，亚板和皮质板反应都存在，但到了 P7，亚板反应被废除。追踪 SRK 中的单个轴突表明，在 P0-P3 时，大量丘脑皮质轴突到达超板，而到 P7-P10 时，上升轴突发育出侧枝进入下层或中层皮质。突触电流也通过全细胞记录在 WT 亚板细胞和 SRK 浅表皮层细胞中得到证实。这些电流是单突触引发的，因为部分 AMPA 电流阻断不会改变潜伏期。这些结果表明，WT 和 SRK 中丘脑轴突和亚板（超板）神经元之间突触形成的一般发育模式非常相似，皮层中的单个丘脑乔木在出生后早期发育过程中进行了相当大的重塑，以找到 IV 层等效神经元。
Transient synapse formation between thalamic axons and subplate neurons is thought to be important in thalamocortical targeting. Shaking rat Kawasaki (SRK), having reversed cortical layering similarly observed in reeler mouse, provides an interesting model system to test this idea. The spatial and temporal pattern of excitation was investigated using optical recording with voltage- sensitive dyes in thalamocortical slice preparations from SRK. At postnatal day 0 ( P0), a strong optical response was elicited within the superplate of the SRK in the cell layer corresponding to subplate in wild- type ( WT) rats. By P3, this response rapidly descended into deep cortical layers comprised of layer IV cells, as identified with 5-bromo-2'-deoxyuridine birthdating at embryonic day 17. During the first 3 postnatal days, both the subplate and cortical plate responses were present, but by P7, the subplate response was abolished. Tracing individual axons in SRK revealed that at P0-P3, a large number of thalamocortical axons reach the superplate, and by P7-P10, the ascending axons develop side branches into the lower or middle cortical layers. Synaptic currents were also demonstrated in WT subplate cells and in SRK superficial cortical cells using whole- cell recording. These currents were elicited monosynaptically, because partial AMPA current blockade did not modify the latencies. These results suggest that the general developmental pattern of synapse formation between thalamic axons and subplate ( superplate) neurons in WT and SRK is very similar, and individual thalamic arbors in cortex are considerably remodeled during early postnatal development to find layer IV equivalent neurons.