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Acta Physiologica 2009; Volume 196, Supplement 671
Scandinavian Physiological Society’s Annual Meeting
8/14/2009-8/16/2009
Uppsala, Sweden
VGLUT1 IN ASTROCYTES IN DIFFERENT BRAIN REGIONS
Abstract number: L32
ORMEL1 L, BERGERSEN1 LH, VOLTERRA1 A, GUNDERSEN1 V
1CMBN and department of anatomy, Sognsvannsveien 9, 0317 Oslo, Norway. [email protected]
The vesicular glutamate transporters (VGLUTs) are necessary for neuronal exocytosis of glutamate. Using the intravesicular proton gradient the VGLUTs carry glutamate into vesicles, enabeling the terminals to exocytose vesicles loaded with glutamate. VGLUTs have been detected in astrocytic synaptic like microvesicles (SLMVs) only in the dentate molecular layers. Here we examine whether the presence of VGLUT1 in astrocytes is a phenomenon that occurs in other brain regions than the dentate molecular layers. For qualitative analysis we used 40 ìm thick sections from perfusion fixed rat brain. The brain regions selected for this study were frontal cortex, striatum, molecular layer and stratum radiatum of the hippocampus. Using immunoflourescence histochemistry, the sections were labeled for glutamin synthetase (astrocytic marker) and VGLUT1. Z-stacks were obtained by confocal microscopy. The quantitative measurements were achieved by immunogold labeling, using sections from the same rat brain regions as in the qualitative analysis. The sections were labeled for GLT (astrocytic marker) and VGLUT1. Point density of VGLUT1 in astrocytes was measured in the electron micrographs. In all the investigated brain regions confocal Z- stacks showed VGLUT1 inside astrocytic processes. In accordance with this, the quantitative immunogold data showed a significant level (p<0,001) of VGLUT1 in astrocytic processes. VGLUT1 was associated with SLMVs in the astrocytic processes from all brain regions included in the study. Our findings suggest that astrocytes in several brain regions are able to load vesicles with glutamate prior to exocytosis.
To cite this abstract, please use the following information:
Acta Physiologica 2009; Volume 196, Supplement 671 :L32