Dipartimento Scienze Mediche di Base, Sezione di Anatomia e Istologia, Università Bari, Italy.
BMC Neurosci. 2011 Nov 17;12:118. doi: 10.1186/1471-2202-12-118.
The aim of this study was to assess the distribution of key SNARE proteins in glutamatergic and GABAergic synapses of the adult rat cerebellar cortex using light microscopy immunohistochemical techniques. Analysis was made of co-localizations of vGluT-1 and vGluT-2, vesicular transporters of glutamate and markers of glutamatergic synapses, or GAD, the GABA synthetic enzyme and marker of GABAergic synapses, with VAMP-2, SNAP-25A/B and syntaxin-1.
The examined SNARE proteins were found to be diffusely expressed in glutamatergic synapses, whereas they were rarely observed in GABAergic synapses. However, among glutamatergic synapses, subpopulations which did not contain VAMP-2, SNAP-25A/B and syntaxin-1 were detected. They included virtually all the synapses established by terminals of climbing fibres (immunoreactive for vGluT-2) and some synapses established by terminals of parallel and mossy fibres (immunoreactive for vGluT-1, and for vGluT-1 and 2, respectively). The only GABA synapses expressing the SNARE proteins studied were the synapses established by axon terminals of basket neurons.
The present study supplies a detailed morphological description of VAMP-2, SNAP-25A/B and syntaxin-1 in the different types of glutamatergic and GABAergic synapses of the rat cerebellar cortex. The examined SNARE proteins characterize most of glutamatergic synapses and only one type of GABAergic synapses. In the subpopulations of glutamatergic and GABAergic synapses lacking the SNARE protein isoforms examined, alternative mechanisms for regulating trafficking of synaptic vesicles may be hypothesized, possibly mediated by different isoforms or homologous proteins.
本研究旨在使用光镜免疫组织化学技术评估成年大鼠小脑皮质谷氨酸能和 GABA 能突触中关键 SNARE 蛋白的分布。分析了谷氨酸转运体 vGluT-1 和 vGluT-2（谷氨酸的囊泡转运体）与谷氨酸能突触标志物，或 GABA 合成酶 GAD（GABA 能突触的标志物）与 VAMP-2、SNAP-25A/B 和 syntaxin-1 的共定位。
所研究的 SNARE 蛋白在谷氨酸能突触中广泛表达，而在 GABA 能突触中很少观察到。然而，在谷氨酸能突触中，检测到不包含 VAMP-2、SNAP-25A/B 和 syntaxin-1 的亚群。它们包括几乎所有由 climbing 纤维末端建立的突触（对 vGluT-2 呈免疫反应性）和由平行纤维和苔藓纤维末端建立的一些突触（对 vGluT-1 呈免疫反应性，对 vGluT-1 和 vGluT-2 分别呈免疫反应性）。唯一表达所研究 SNARE 蛋白的 GABA 突触是 basket 神经元轴突末端建立的突触。
本研究提供了大鼠小脑皮质不同类型谷氨酸能和 GABA 能突触中 VAMP-2、SNAP-25A/B 和 syntaxin-1 的详细形态描述。所研究的 SNARE 蛋白可表征大多数谷氨酸能突触和仅一种 GABA 能突触。在缺乏所研究的 SNARE 蛋白同工型的谷氨酸能和 GABA 能突触亚群中，可能假设存在调节囊泡转运的替代机制，可能由不同同工型或同源蛋白介导。
