Organization of GABAA receptor α-subunit clustering in the developing rat neocortex and hippocampus
Organization of GABAA receptor α-subunit clustering in the developing rat neocortex and hippocampus
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DOI：
10.1111/j.0953-816x.2004.03349.x
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发表时间：
2004-05-01
影响因子：
3.4
通讯作者：
Poulter, MO
中科院分区：
文献类型：
--
作者：
Hutcheon, B;Fritschy, JM;Poulter, MO
我们比较了出生后5-10天和30-40天大鼠新皮质和海马中γ -氨基丁酸（GABA）受体α 1、α 2、α 3和α 5亚基蛋白团的表达和共表达，以了解脑成熟过程中抑制性受体的重组情况。荧光标记亚基簇的大小、强度、密度和共定位模式是通过一种新的二维交叉相关分析在反卷积数字图像中确定的。交叉相关分析允许基于染色强度的GABA(A)受体亚基簇的无偏鉴定。集群规模随着发展而增加；只有齿状回（DG）的alpha2簇变小。α - 5亚基簇密度随脑区的成熟而增加或减少。对于其他亚单位，簇密度保持相当稳定，但有例外（皮层第5层的alpha2簇增加，而门窝的alpha3簇减少）。α 1亚基与其他亚基的共定位是独特的，与不同发育时期亚基丰度的总体变化无关。因此，尽管alpha2亚基在DG中的表达增加，但这些簇与alpha1的共定位减少了。相比之下，随着alpha5亚基在皮层和CA1中的表达下降，alpha5亚基簇与alpha1的共定位更加明显。alpha3与alpha1的共定位在第6层也变得更大。在成人大脑中，并不是所有的聚类都与突触有关，因为许多α -亚单位聚类并不与突触素共定位。总的来说，这些数据表明GABA(A)受体聚集的调节是突触和突触外的，可能反映了复杂的细胞运输机制。
We compared the expression and co-expression of alpha1, alpha2, alpha3, and alpha5-subunit protein clusters of the gamma-aminobutyric acid (GABA)(A) receptor in the neocortex and hippocampus of rat at postnatal days (PND) 5-10 and 30-40 in order to understand how inhibitory receptors reorganize during brain maturation. The size, intensity, density and pattern of co-localization of fluorescently tagged subunit clusters were determined in deconvolved digital images using a novel 2D cross-correlational analysis. The cross-correlation analysis allowed an unbiased identification of GABA(A) receptor subunit clusters based on staining intensity. Cluster size increased through development; only the alpha2 clusters in dentate gyrus (DG) decreased in size. alpha5-subunit cluster density either increased or decreased with maturation depending on the brain region. For the other subunits, the cluster density remained rather constant, with noted exceptions (increase in alpha2 clusters in cortical layer 5 but a decrease of alpha3 clusters in hilus). The co-localization of alpha1-subunit with the others was unique and not correlated to overall changes in subunit abundance between developmental epoques. So, although alpha2-subunit expression went up in the DG, the clusters became less co-localized with alpha1. In contrast, alpha5-subunit clusters became more co-localized with alpha1 as the alpha5-subunit expression declined in cortex and CA1. The co-localization of alpha3 with alpha1 also became greater in layer 6. In the adult brain not all clustering was associated with synapses, as many alpha-subunit clusters did not co-localize with synaptophysin. Overall, these data indicate that the regulation of GABA(A) receptor clustering is both synaptic and extrasynaptic, presumably reflecting complex cellular trafficking mechanisms.