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Synaptic and vesicular co‐localization of the glutamate transporters VGLUT1 and VGLUT2 in the mouse hippocampus
Author(s) -
Herzog Etienne,
Takamori Shigeo,
Jahn Reinhard,
Brose Nils,
Wojcik Sonja M.
Publication year - 2006
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2006.04144.x
Subject(s) - glutamatergic , synaptic vesicle , neuroscience , hippocampal formation , vesicle , biology , hippocampus , glutamate receptor , synapse , chemistry , microbiology and biotechnology , biochemistry , receptor , membrane
Vesicular glutamate transporters (VGLUTs) are essential to glutamatergic synapses and determine the glutamatergic phenotype of neurones. The three known VGLUT isoforms display nearly identical uptake characteristics, but the associated expression domains in the adult rodent brain are largely segregated. Indeed, indirect evidence obtained in young VGLUT1‐deficient mice indicated that in cells that co‐express VGLUT1 and VGLUT2, the transporters may be targeted to different synaptic vesicles, which may populate different types of synapses formed by the same neurone. Direct evidence for a systematic segregation of VGLUT1 and VGLUT2 to distinct synapses and vesicles is lacking, and the mechanisms that may convey this segregation are not known. We show here that VGLUT1 and VGLUT2 are co‐localized in many layers of the young hippocampus. Strikingly, VGLUT2 co‐localizes with VGLUT1 in the mossy fibers at early stages. Furthermore, we show that a fraction of VGLUT1 and VGLUT2 is carried by the same vesicles at these stages. Hence, hippocampal neurones co‐expressing VGLUT1 and VGLUT2 do not appear to sort them to separate vesicle pools. As the number of transporter molecules per vesicle affects quantal size, the developmental window where VGLUT1 and VGLUT2 are co‐expressed may allow for greater plasticity in the control of quantal release.