Western blot and fluorescent immunostaining of α7 nAChR in rat microglial cultures. A: Proteins from microglial cultures and PC12 cells were analysed by western blot (50 ug/lane) using specific polyclonal anti AChRα7 antibodies. B: microglial cells were pre-incubated in the absence (B, left panel) or presence of 500 μM nicotine (B, right panel) for 10 min and then incubated with FITC-labeleled-α-Bgtx (1.5 μg/ml) for 15 min at 4°C. A strong binding of α-Bgtx was observed on the cell surface of microglial cells. Nicotine pre-treatment resulted in a marked reduction of the intensity of binding.