在皮质轴突终末的亚群中,VGLUT1和VGAT被分选到同一群突触小泡中。
VGLUT1 and VGAT are sorted to the same population of synaptic vesicles in subsets of cortical axon terminals.
作者信息
Fattorini Giorgia, Verderio Claudia, Melone Marcello, Giovedì Silvia, Benfenati Fabio, Matteoli Michela, Conti Fiorenzo
机构信息
Department of Neuroscience, Università Politecnica delle Marche, Ancona, Italy.
出版信息
J Neurochem. 2009 Sep;110(5):1538-46. doi: 10.1111/j.1471-4159.2009.06251.x. Epub 2009 Jul 15.
Glutamate and GABA mediate most of the excitatory and inhibitory synaptic transmission; they are taken up and accumulated in synaptic vesicles by specific vesicular transporters named VGLUT1-3 and VGAT, respectively. Recent studies show that VGLUT2 and VGLUT3 are co-expressed with VGAT. Because of the relevance this information has for our understanding of synaptic physiology and plasticity, we investigated whether VGLUT1 and VGAT are co-expressed in rat cortical neurons. In cortical cultures and layer V cortical terminals we observed a population of terminals expressing VGLUT1 and VGAT. Post-embedding immunogold studies showed that VGLUT1+/VGAT+ terminals formed both symmetric and asymmetric synapses. Triple-labeling studies revealed GABAergic synapses expressing VGLUT1 and glutamatergic synapses expressing VGAT. Immunoisolation studies showed that anti-VGAT immunoisolated vesicles contained VGLUT1 and anti-VGLUT1 immunoisolated vesicles contained VGAT. Finally, vesicles containing VGAT resident in glutamatergic terminals undergo active recycling. In conclusion, we demonstrate that in neocortex VGLUT1 and VGAT are co-expressed in a subset of axon terminals forming both symmetric and asymmetric synapses, that VGLUT1 and VGAT are sorted to the same vesicles and that vesicles at synapses expressing the vesicular heterotransporter participate in the exo-endocytotic cycle.
谷氨酸和γ-氨基丁酸(GABA)介导了大部分兴奋性和抑制性突触传递;它们分别通过名为VGLUT1 - 3和VGAT的特定囊泡转运体被摄取并积累在突触小泡中。最近的研究表明,VGLUT2和VGLUT3与VGAT共同表达。鉴于此信息对于我们理解突触生理学和可塑性的相关性,我们研究了VGLUT1和VGAT在大鼠皮层神经元中是否共同表达。在皮层培养物和V层皮层终末中,我们观察到一群表达VGLUT1和VGAT的终末。包埋后免疫金研究表明,VGLUT1 + / VGAT +终末形成了对称和不对称突触。三重标记研究揭示了表达VGLUT1的GABA能突触和表达VGAT的谷氨酸能突触。免疫分离研究表明,抗VGAT免疫分离的囊泡含有VGLUT1,抗VGLUT1免疫分离的囊泡含有VGAT。最后,存在于谷氨酸能终末中的含有VGAT的囊泡进行活跃的再循环。总之,我们证明在新皮层中,VGLUT1和VGAT在形成对称和不对称突触的轴突终末亚群中共同表达,VGLUT1和VGAT被分选到相同的囊泡中,并且在表达囊泡异源转运体的突触处的囊泡参与胞吐 - 内吞循环。