He Y, Janssen W G, Morrison J H
Fishberg Research Center for Neurobiology and Neurobiology of Aging Laboratories, Mount Sinai School of Medicine, New York, NY 10029, USA.
Brain Res. 1999 May 8;827(1-2):51-62. doi: 10.1016/s0006-8993(99)01264-0.
The cellular and ultrastructural distribution patterns of the AMPA glutamate receptor subunit, GluR2, were determined in the rat basolateral amygdala. GluR2 immunoreactivity was widely and uniformly distributed in the basolateral nucleus, with both pyramidal and non-pyramidal neurons labelled. In fact, double label immunohistochemical analyses demonstrated that over 90% of the GABAergic interneurons were labelled for GluR2. Electron microscopic analyses further confirmed the presence of GluR2 in the soma and dendrites of GABAergic interneurons as well as in the soma, spines and dendritic shafts of pyramidal cells. As in our parallel study in the rat hippocampus, immunogold analyses revealed that GluR2 immunoreactivity was frequently preferentially located at asymmetric synapses on both pyramidal cell spines and shafts, as well as the dendritic processes and soma of GABAergic interneurons. However, the number of immunogold particles per labelled synapse on GABAergic neurons was significantly lower than at similar labelled asymmetric synapses on spines of presumed pyramidal cells. Given that the presence of GluR2 within the AMPA receptor complex decreases calcium flux, these data indicate that GABAergic local circuit neurons might possess AMPA receptors with higher calcium permeability on average than pyramidal cells, as has been suggested for hippocampus. Such cell class-specific differences in the subunit representation and resultant channel properties of AMPA receptors have implications for response properties as well as selective vulnerability of neurons within the basolateral nucleus of the amygdala.
在大鼠基底外侧杏仁核中确定了AMPA型谷氨酸受体亚基GluR2的细胞和超微结构分布模式。GluR2免疫反应性广泛且均匀地分布于基底外侧核，锥体细胞和非锥体细胞均有标记。事实上，双重标记免疫组织化学分析表明，超过90%的GABA能中间神经元被标记为GluR2。电子显微镜分析进一步证实了GABA能中间神经元的胞体和树突以及锥体细胞的胞体、棘突和树突干中存在GluR2。正如我们在大鼠海马体的平行研究中一样，免疫金分析显示，GluR2免疫反应性经常优先位于锥体细胞棘突和树突干以及GABA能中间神经元的树突突起和胞体上的不对称突触处。然而，GABA能神经元上每个标记突触的免疫金颗粒数量明显低于假定锥体细胞棘突上类似标记的不对称突触处。鉴于AMPA受体复合物中GluR2的存在会降低钙通量，这些数据表明，GABA能局部回路神经元可能平均拥有比锥体细胞具有更高钙通透性的AMPA受体，正如海马体所显示的那样。AMPA受体亚基表达及由此产生的通道特性的这种细胞类别特异性差异对杏仁核基底外侧核内神经元的反应特性以及选择性易损性具有影响。
