Noradrenergic innervation of pyramidal cells in the rat basolateral amygdala.
Noradrenergic innervation of pyramidal cells in the rat basolateral amygdala.
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DOI：
10.1016/j.neuroscience.2012.10.035
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发表时间：
2013-01-03
期刊：
影响因子：
3.3
通讯作者：
McDonald AJ
中科院分区：
文献类型：
--
作者：
Zhang J;Muller JF;McDonald AJ
杏仁核基底外侧复合体（BLC）接受来自蓝斑的密集去甲肾上腺素（NE）输入，在调节情绪记忆巩固中起关键作用。NE输入BLC的突触形成的程度，以及受神经支配的细胞类型的知识，将有助于了解NE如何调节BLC的活动。为了更好地了解BLC中NE回路的情况，本研究采用免疫组织化学双标记技术，在光镜和电镜水平上分析了基底外侧杏仁核（BLa）前亚部锥体细胞的NE轴突及其神经支配。NE轴突和BLa锥体细胞分别用去甲肾上腺素转运蛋白（NET）和钙/钙调蛋白依赖性蛋白激酶（CaMK）的抗体进行标记。使用NET和多巴胺-β-羟化酶（DBH）抗体的双重定位研究表明，几乎所有NE轴突和静脉曲张表达这两种蛋白质。BLa表现出中等密度的NET+纤维。NET+轴突连续切片重建的超微结构分析显示，只有约一半的NET+终端形成突触。突触后作用的主要靶点是小口径的CaMK+树突轴和锥体细胞棘。少数NET+终末与未标记的胞体和树突形成突触。这些结果表明，远端树突状结构域的BLa锥体细胞是NE终端在BLa的主要目标，和相对较低的突触发生率表明，从非突触终端的扩散可能是重要的去甲肾上腺素调制的BLa。
The basolateral nuclear complex of the amygdala (BLC) receives dense noradrenergic (NE) inputs from the locus coeruleus that plays a key role in modulating emotional memory consolidation. Knowledge of the extent of synapse formation by NE inputs to the BLC, as well as the cell types innervated, would contribute to an understanding of how NE modulates the activity of the BLC. To gain a better understanding of NE circuits in the BLC, dual-label immunohistochemistry was used at the light and electron microscopic levels in the present study to analyze NE axons and their innervation of pyramidal cells in the anterior subdivision of the basolateral amygdalar nucleus (BLa). NE axons and BLa pyramidal cells were labeled using antibodies to the norepinephrine transporter (NET) and Ca2+/calmodulin-dependent protein kinase (CaMK), respectively. Dual localization studies using antibodies to NET and dopamine-beta-hydroxylase (DBH) revealed that virtually all NE axons and varicosities expressed both proteins. The BLa exhibited a medium density of NET+ fibers. Ultrastructural analysis of serial section reconstructions of NET+ axons revealed that only about half of NET+ terminals formed synapses. The main postsynaptic targets were small-caliber CaMK+ dendritic shafts and spines of pyramidal cells. A smaller number of NET+ terminals formed synapses with unlabeled cell bodies and dendrites. These findings indicate that the distal dendritic domain of BLa pyramidal cells is the major target of NE terminals in the BLa, and the relatively low synaptic incidence suggests that diffusion from non-synaptic terminals may be important for noradrenergic modulation of the BLa.