Figure 1: Cotinine protects neurons against Aβ toxicity by a mechanism independent of the nicotinic acetylcholine receptors. Embryonic cortical neurons after 7 DIV were treated with 5μM Aβ either alone or with cotinine (0.1, 1, 10 μM). After 24 h, cell viability was assessed using double calcein- AM and PI staining (Scale bar = 20 μm) (A). MTT analysis of cell viability of cells exposed to pre-aggregated Aβ1-42 solutions for 24 h at 37°C in absence or presence of cotinine alone or plus mecamylamine (B). The values were normalized against control values considered 100% and represent the mean ± S.E.M.. The differences of the mean were considered significant with p < 0.05 (*), p < 0.01 (**), p < 0.001 (***). ns (not significant).