Catania M V, Bellomo M, Giuffrida R, Giuffrida R, Stella A M, Albanese V
Istituto di Bioimmagini e Fisiopatologia del Sistema Nervoso Centrale, Consiglio Nazionale dell Ricerche, Catania, Italy.
Eur J Neurosci. 1998 Nov;10(11):3479-90. doi: 10.1046/j.1460-9568.1998.00356.x.
Recent studies suggest a functional diversity of native alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate-type glutamate receptor channels (AMPARs). In several types of interneurons, AMPARs are characterized by higher Ca2+ permeability and faster kinetics than AMPARs in principal cells. We studied the expression profile of AMPAR subunits in the hippocampal parvalbumin (PV)- and calretinin (CR)-positive cells, which represent different populations of non-principal cells. To this end, non-radioactive in situ hybridization with AMPAR subunit specific cRNAs was combined with immunocytochemistry for PV or CR. Double-immunolabelling using antibodies against AMPAR subunits and PV or CR was also performed. PV-containing neurons represent a fairly homogeneous population of cells expressing high levels of GluR-A and GluR-D mRNAs, moderate levels of GluR-C and low levels of GluR-B mRNAs in all the examined regions of hippocampus. The vast majority of CR-containing cells have a much lower expression of GluR-A, -C and -D mRNA than PV-positive neurons, although similarly featuring low levels of GluR-B mRNA. Only a subpopulation of CR-containing cells, the spiny neurons of the dentate gyrus and CA3 region of the hippocampus were characterized by a strong expression of GluR-A and -D subunit mRNAs. The differential pattern found for the AMPAR subunit mRNA expression was confirmed by immunocytochemistry at protein level. Despite the common feature of low GluR-B subunit expression, PV- and CR-containing interneurons differ with respect to the density and combination of their expressed AMPAR subunits. The different combination of subunits might subserve different properties of the AMPA channels featured by these cell types, with implications for the functioning of the hippocampal network.
近期研究表明，天然α-氨基-3-羟基-5-甲基-4-异恶唑丙酸型谷氨酸受体通道（AMPARs）具有功能多样性。在几种类型的中间神经元中，与主细胞中的AMPARs相比，AMPARs具有更高的Ca2+通透性和更快的动力学特性。我们研究了海马小白蛋白（PV）和钙视网膜蛋白（CR）阳性细胞中AMPAR亚基的表达谱，这些细胞代表了不同群体的非主细胞。为此，将针对AMPAR亚基特异性cRNAs的非放射性原位杂交与针对PV或CR的免疫细胞化学相结合。还使用针对AMPAR亚基和PV或CR的抗体进行了双重免疫标记。在海马所有被检查区域中，含PV的神经元代表了一个相当同质的细胞群体，它们高水平表达GluR-A和GluR-D mRNA，中等水平表达GluR-C mRNA，低水平表达GluR-B mRNA。绝大多数含CR的细胞中，GluR-A、-C和-D mRNA的表达比PV阳性神经元低得多，尽管同样具有低水平的GluR-B mRNA。只有含CR细胞的一个亚群，即海马齿状回和CA3区的棘状神经元，其特征是强烈表达GluR-A和-D亚基mRNA。通过蛋白质水平的免疫细胞化学证实了AMPAR亚基mRNA表达的差异模式。尽管存在GluR-B亚基低表达的共同特征，但含PV和含CR的中间神经元在其表达的AMPAR亚基的密度和组合方面存在差异。亚基的不同组合可能有助于这些细胞类型所具有的AMPA通道的不同特性，这对海马网络的功能具有重要意义。
