Glial fibrillary acidic protein is strongly and specifically expressed in astrocytes and certain other astroglia present in the brain. The protein was targeted in the section of rat hypothalamus featured in this confocal image with rabbit anti-GFAP primary antibodies followed by goat anti-rabbit secondary antibodies conjugated to Alexa Fluor 568. The intermediate filament protein vimentin was also targeted in the tissue section with a mouse anti-vimentin antibody detected with a goat anti-mouse secondary antibody conjugated to Alexa Fluor 488. Cell nuclei were counterstained with DRAQ5 (pseudocolored blue). Images were recorded with a 40x oil immersion objective using a zoom factor of 1.8 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser, the 543-nanometer line from a green helium-neon laser, and the 633-nanometer line of a red helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles unless otherwise noted above.