VGLUT2 immunoreactivity in TRPM5-GFP and GAD67-GFP mice. Laser scanning confocal images illustrate the expression of GFP under the control of the TRPM5 promoter (green), VGLUT2 (red) and P2X2 (blue) in circumvallate papillae (CV; A-D), fungiform papillae (FF; E-H). Panels I-K represent VGLUT2 immunoreactivity in GAD67-GFP mice. In fungiform and circumvallate taste buds, VGLUT2 is not expressed in taste cells but only in nerve fibers surrounding these taste cells. Moreover, the VGLUT2-positive fibers are co-localized with P2X2 fibers, a marker for gustatory fibers. Each figure represents merged images from a Z-series.