BDNF and Alzheimer disease: Animal studies demonstrated that neuropeptide Y increases significantly in hippocampus mouse Alzheimer’s disease and exerts neuroprotective effects through activation of PI3K-XBP1-induced Gip78/BiP pathway and inhibition of caspase-3 and caspase-4 activities, suppresses oxidative stress via inhibition of Aβ induced lipid peroxidation and modulates the level of BDNF [68].