Effects of specific α7 nAChR agonist and antagonist on TNF-α production by activated rat microglial cultures. Microglial cells were subcultured for 24 h in 10% FCS-containing medium, which was replaced with fresh medium before stimulation. Nicotine (0.1–1 μM) and/or α-Bgtx were added 30 min before LPS stimulation (10 ng/ml). Supernatants were collected after 4 h and analyzed for TNF-α content. Data are shown as mean ± SEM for 3 independent experiments, run in duplicate. *p < 0.03 vs LPS.