Vesicular glutamate transporters VGLUT1 and VGLUT2 in the developing mouse barrel cortex

Abstract

Three vesicular glutamate transporters have been identified in mammals. Two of them, VGLUT1 and VGLUT2, define the glutamatergic phenotype and their distribution in the brain is almost complementary. In the present study we examined the distribution and expression levels of these two VGLUTs during postnatal development of the mouse barrel cortex. We also investigated changes in the localization of VGLUT1 and VGLUT2 within particular compartments of the barrel field (barrels/septa) during its development. We found differences in the time course of developmental expression, with VGLUT1 peaking around P14, while VGLUT2 increased gradually until adulthood. Over the examined period (P3 - adult) both transporters had stronger expression in the barrel interiors, and in this compartment VGLUT2 dominated, whereas in the inter-barrel septa VGLUT1 dominated over VGLUT2. Furthermore, we found that some nerve terminals in the barrel cortex coexpressed both transporters until adulthood. Colocalization was observed within the barrels, but not within the septa.

Differential Inputs to the Perisomatic and Distal-Dendritic Compartments of VIP-Positive Neurons in Layer 2/3 of the Mouse Barrel Cortex

“…We developed a new procedure for fluorescence visualization of CO activity to identify barrels and septa through comparison with VGluT2 immunofluorescence and DAPI counterstaining (Figures 9A–G). VGluT2-immunoreactivity, which is more densely distributed in barrels than in septa (Figures 9B,E; Liguz-Lecznar and Skangiel-Kramska, 2007), as well as VGAT- and PV-positive axon terminals, showed significantly higher densities in barrels than in septa (Figures 9H,I). In contrast, SOM- and VIP-positive axon terminals were more abundant in septa (Figure 9I).…”

Gene Expression Identifies Distinct Ascending Glutamatergic Pathways to Frequency-Organized Auditory Cortex in the Rat Brain

“…Prior studies suggest coexpression of VGLUT1 and VGLUT2 allow for high response magnitudes and rates at corresponding synapses. VGLUT2 is expressed early in development and current theories suggest the highly reliable glutamate release associated with VGLUT2 is needed to establish thalamocortical sensory pathways (Nakamura et al, 2005;Liguz-Lecznar and Skangiel-Kramska, 2007). The sensitivity and magnitude of thalamocortical sensory responses increase during development (Zhang et al, 2001).…”

A developmental cell-type switch in cortical interneurons leads to a selective defect in cortical oscillations

“…Fluorescence images were taken using LSM710 confocal laser-scanning microscope (Zeiss). VGluT2 staining was used to visualize barrel structures of the somatosensory barrel cortex, based on the dense labelling of axon terminals from thalamocortical projections49. The specific interneuron cell types were counted manually using FIJI image processing software.…”