Exuberant thalamocortical axon arborization in cortex-specific NMDAR1 knockout mice
Exuberant thalamocortical axon arborization in cortex-specific NMDAR1 knockout mice
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DOI：
10.1002/cne.20481
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发表时间：
2005-05-16
影响因子：
2.5
通讯作者：
Erzurumlu, RS
中科院分区：
文献类型：
--
作者：
Lee, LJ;Iwasato, T;Erzurumlu, RS
在啮齿动物的躯体感觉系统中发展胡须特异性神经模式需要NMDAR(NMDAR)介导的活动。在皮层特异性NR1基因敲除(CxNR1KO)小鼠中，虽然丘脑皮质传入(TCA)在初级躯体感觉(Barrel)皮质中形成了基本的胡须特定模式，但IV层细胞不发育桶或将其树突定向到TCA。为了确定突触后NMDAR在突触前传入发育和桶状皮质模式中的作用，我们研究了出生后1-7天的CxNR1KO小鼠的单个TCA树枝。CxNR1KO小鼠和对照组小鼠一样，稀疏分枝的TCA侵入P1的皮质板。在对照组动物中，TCA逐渐细化成片状终末，主要局限于第IV层。在CxNR1KO小鼠中，TCA在P3-7之间发育出更广泛的乔木。从P3开始，它们的侧向范围是对照组的两倍。到P7时，CxNR1KO TCA在第IV层和第VI层的分支点和终末数显著少于对照组，而在第II/III层和第V层的分支点和终末数明显多于对照组。在扩张的终端乔木内，CxNR1KO TCA在IV层形成焦点终端密度，对应于原始的晶须特定斑块。鉴于丘脑NMDAR在CxNR1KO小鼠中是不存在的，目前的结果表明，突触后NMDAR在突触前传入乔木和发育中的桶形皮质中的胡须特异性图案的提炼中发挥着重要作用。(C)2005年Wiley-Liss，Inc.
Development of whisker-specific neural patterns in the rodent somatosensory system requires NMDA receptor (NMDAR)-mediated activity. In cortex-specific NR1 knockout (CxNR1KO) mice, while thalamocortical afferents (TCAs) develop rudimentary whisker specific patterns in the primary somatosensory (barrel) cortex, layer IV cells do not develop barrels or orient their dendrites towards TCAs. To determine the role of postsynaptic NMDARs in presynaptic afferent development and patterning in the barrel cortex, we examined the single TCA arbors in CxNR1KO mice between postnatal days (P) 1-7. Sparsely branched TCAs invade the cortical plate on P1 in CxNR1KO mice as in control mice. In control animals, TCAs progressively elaborate patchy terminals, mostly restricted to layer IV. In CxNR1KO mice, TCAs develop far more extensive arbors between P3-7. Their lateral extent is twice that of controls from P3 onwards. By P7, CxNR1KO TCAs have significantly fewer branch points and terminal endings in layers IV and VI but more in layers II/III and V than control mouse TCAs. Within expansive terminal arbors, CxNR1KO TCAs develop focal terminal densities in layer IV, corresponding to the rudimentary whisker-specific patches. Given that thalamic NMDARs are spared in CxNR1KO mice, the present results show that postsynaptic NMDARs play an important role in refinement of presynaptic afferent arbors and whisker-specific patterning in the developing barrel cortex. (c) 2005 Wiley-Liss, Inc.