Immunohistochemical verification of tdTomato-expressing cells as GAD65-positive interneurons in GAD65-tdTomato mice.

<p>An antibody raised against GAD65 (green) was used to identify tdTomato-positive cells as GABAergic neurons in 2.5 month old mice. <b>A:</b> cortex; <b>B:</b> hippocampus; <b>C:</b> brainstem; <b>D:</b> olfactory bulb. All nuclei were stained with DAPI (blue). Arrows highlight examples of cells expressing both tdTomato and GAD65. The scale bar corresponds to 50 μm and applies to all panels. <b>E:</b> Quantification of cells expressing tdTomato in the absence of GAD65-immunoreactivity (red); GAD65-positive cells lacking tdTomato fluorescence (green) as well as neurons simultaneously expressing tdTomato and endogenous GAD65 (yellow). While 10% to 20% of GAD65 expressing neurons do not express tdTomato, almost all cells showing tdTomato fluorescence are indeed GAD65-positive GABAergic neurons.