GABA and glutamate are not colocalized in mossy fiber terminals of developing rodent hippocampus

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• 作者：Guoxiang Xiong ; Lei Zhang ; Jelena Mojsilovic-Petrovic ; Edguardo Arroyo ; Jaclynn Elkind ; Suhali Kundu ; Brian Johnson ; Colin J. Smith ; Noam A. Cohen ; Sean M. Grady ; Akiva S. Cohen
• 关键词：Granule cell ; Vesicular glutamate transporter ; Vesicular GABA transporter ; Immunofluorescence ; Synaptic button
• 刊名：Brain Research
• 出版年：2012
• 出版时间：20 September, 2012
• 年：2012
• 卷：1474
• 期：Complete
• 页码：40-49
• 全文大小：3594 K

文摘

It has been hypothesized that, in the developing rodent hippocampus, mossy fiber terminals release GABA together with glutamate. Here, we used transgenic glutamic acid decarboxylase-67 (GAD67)-GFP expressing mice and multi-label immunohistochemistry to address whether glutamatergic and GABAergic markers are colocalized. We demonstrate that in the dentate gyrus, interneurons positive for GABA/GAD are sparsely distributed along the edge of the hilus, in a different pattern from that of the densely packed granule cells. Co-staining for synaptophysin and vesicular glutamate transporter1 (VGLUT1) in postnatal day 14 brain sections from both mice and rats showed mossy fiber terminals as a group of large (2-5 ¦Ìm in diameter) VGLUT1-positive excitatory presynaptic terminals in the stratum lucidum of area CA3a/b. Furthermore, co-staining for synaptophysin and vesicular GABA transporter (VGAT) revealed a group of small-sized (¡«0.5 ¦Ìm in diameter) inhibitory presynaptic terminals in the same area where identified mossy fiber terminals were present. The two types of terminals appeared to be mutually exclusive, and showed no colocalization. Thus, our results do not support the hypothesis that GABA is released as a neurotransmitter from mossy fiber terminals during development.