Pinard C R, Muller J F, Mascagni F, McDonald A J
Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, 6439 Garner's Ferry Rd, VA Building 1, D-46, Columbia, SC 29208, USA.
Neuroscience. 2008 Dec 10;157(4):850-63. doi: 10.1016/j.neuroscience.2008.09.043. Epub 2008 Oct 2.
The basolateral nuclear complex of the amygdala (BLC) receives a dense dopaminergic innervation that plays a critical role in the formation of emotional memory. Dopamine has been shown to influence the activity of BLC GABAergic interneurons, which differentially control the activity of pyramidal cells. However, little is known about how dopaminergic inputs interface with different interneuronal subpopulations in this region. To address this question, dual-labeling immunohistochemical techniques were used at the light and electron microscopic levels to examine inputs from tyrosine hydroxylase-immunoreactive (TH+) dopaminergic terminals to two different interneuronal populations in the rat basolateral nucleus labeled using antibodies to parvalbumin (PV) or calretinin (CR). The basolateral nucleus exhibited a dense innervation by TH+ axons. Partial serial section reconstruction of TH+ terminals found that at least 43-50% of these terminals formed synaptic junctions in the basolateral nucleus. All of the synapses examined were symmetrical. In both TH/PV and TH/CR preparations the main targets of TH+ terminals were spines and distal dendrites of unlabeled cells. In sections dual-labeled for TH/PV 59% of the contacts of TH+ terminals with PV+ neurons were synapses, whereas in sections dual-labeled for TH/CR only 13% of the contacts of TH+ terminals with CR+ cells were synapses. In separate preparations examined in complete serial sections for TH+ basket-like innervation of PV+ perikarya, most (76.2%) of TH+ terminal contacts with PV+ perikarya were synapses. These findings suggest that PV+ interneurons, but not CR+ interneurons, are prominent synaptic targets of dopaminergic terminals in the BLC.
杏仁核基底外侧核复合体（BLC）接受密集的多巴胺能神经支配，这在情绪记忆形成中起关键作用。多巴胺已被证明会影响BLC GABA能中间神经元的活动，这些中间神经元可差异性地控制锥体细胞的活动。然而，关于多巴胺能输入如何与该区域不同的中间神经元亚群相互作用，我们知之甚少。为解决这个问题，我们在光镜和电镜水平上使用双标记免疫组化技术，来检测来自酪氨酸羟化酶免疫反应阳性（TH+）多巴胺能终末到大鼠基底外侧核中两个不同中间神经元群体的输入，这两个群体分别用小白蛋白（PV）或钙视网膜蛋白（CR）抗体进行标记。基底外侧核呈现出TH+轴突的密集神经支配。对TH+终末进行部分连续切片重建发现，这些终末中至少43%-50%在基底外侧核中形成了突触连接。所有检查的突触都是对称性的。在TH/PV和TH/CR标本中，TH+终末的主要靶点都是未标记细胞的棘突和远端树突。在TH/PV双标记切片中，TH+终末与PV+神经元的接触中有59%是突触，而在TH/CR双标记切片中，TH+终末与CR+细胞的接触中只有13%是突触。在对PV+胞体进行TH+篮状神经支配的完整连续切片检查的单独标本中，TH+终末与PV+胞体的大多数（76.2%）接触都是突触。这些发现表明，PV+中间神经元而非CR+中间神经元，是BLC中多巴胺能终末的主要突触靶点。
