Activation of α7nAChR with nicotine protects hippocampal neurons from Aβ fibers. (A) Hippocampal neurons (10 DIV) were expose to Aβ1–40 fibers 5 mM for 6 h in the absence or presence of nicotine 10 μM. The immunostainings of the protein neurofilament (NF) shows the loss of dendrites, and the presynaptic protein SV-2, show a significant reduction upon exposure to Aβ. Nicotine is able to overturn the damage cause by Aβ. This reversion is specific to the nicotinic receptor since this protective effect was blocked by α-bungarotoxin (100 nM). (B) These effects are observed by western-blot of the total levels of total β-catenin, in which the reduction of β-catenin is prevented by nicotine and blocked with α-BTX.