Boscia Francesca, Ferraguti Francesco, Moroni Flavio, Annunziato Lucio, Pellegrini-Giampietro Domenico E
Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples "Federico II", Via S. Pansini 5, 80131 Naples, Italy.
Neuropharmacology. 2008 Sep;55(4):428-39. doi: 10.1016/j.neuropharm.2008.04.024. Epub 2008 May 14.
Recent studies have demonstrated a functional interaction between group I metabotropic glutamate (mGlu) receptors and the cannabinoid system in the modulation of synaptic transmission. By using antisera directed against mGlu1alpha and CB1 cannabinoid receptors, we examined their distribution in the CA1 region of rat organotypic hippocampal slice cultures. Immunoreactive mGlu1alpha and CB1 elements were localized in non-principal cells, with a labeling distribution that was very similar to the pattern previously observed in the adult rat brain. Double-immunofluorescence staining and confocal microscopy showed that a subset of interneurons, mainly located in the stratum radiatum, was double-labeled for both mGlu1alpha and CB1 receptors. Co-localization of the two receptor subtypes was confirmed in hippocampal sections from adult rat brain. By using the "mirror technique" in adjacent sections, we observed that the double-labeled cells for mGlu1alpha and CB1 receptors were also immunopositive for the cholecystokinin peptide. Quantitative analysis revealed that in the stratum radiatum the majority (92%) of the CB1-positive cells and 19% of the mGlu1alpha-positive cells expressed both receptors. Triple immunofluorescence staining showed partial co-labeling of mGlu1alpha- and CB1-immunopositive cells with the vesicular glutamate transporter 3 or calbindin. Our results demonstrate that mGlu1alpha and CB1 receptors co-exist in a subpopulation of inhibitory neurons in the stratum radiatum of the hippocampus that is suggestive of the Schaffer collateral-associated interneurons. Hence, additional functional mechanisms underlying the cooperation between these two receptor subtypes may exist.
最近的研究表明，I 型代谢型谷氨酸（mGlu）受体与大麻素系统在调节突触传递方面存在功能相互作用。通过使用针对 mGlu1α 和 CB1 大麻素受体的抗血清，我们检测了它们在大鼠器官型海马切片培养物 CA1 区的分布。免疫反应性 mGlu1α 和 CB1 元件定位于非主细胞中，其标记分布与先前在成年大鼠脑中观察到的模式非常相似。双重免疫荧光染色和共聚焦显微镜显示，主要位于辐射层的一部分中间神经元同时被 mGlu1α 和 CB1 受体双重标记。在成年大鼠脑的海马切片中证实了这两种受体亚型的共定位。通过在相邻切片中使用“镜像技术”，我们观察到 mGlu1α 和 CB1 受体的双重标记细胞对胆囊收缩素肽也呈免疫阳性。定量分析显示，在辐射层中，大多数（92%）CB1 阳性细胞和 19% 的 mGlu1α 阳性细胞表达了这两种受体。三重免疫荧光染色显示 mGlu1α 和 CB1 免疫阳性细胞与囊泡谷氨酸转运体 3 或钙结合蛋白存在部分共标记。我们的结果表明，mGlu1α 和 CB1 受体共存于海马辐射层中一部分抑制性神经元中，提示这些神经元与谢弗侧支相关。因此，这两种受体亚型之间合作的潜在功能机制可能还有其他。
