BDNF expression induced by peripheral inflammation occurred in all types of cells. A–C, Double-immunostaining shows that BDNF immunostaining colocalized with the astrocyte marker GFAP (A, arrows), but also with the microglial marker Iba1 (B, arrows), and NeuN (C, arrows), a neuronal marker. Cells positive for BDNF, but negative for the relevant marker, were also observed and are indicated here with arrowheads. Scale bars: A, B, 20 μm; C, 50 μm.