NGF and Alzheimer disease: To assess whether insulin resistance of cholinergic neurons can be rescued from NGF also in vivo, young adult 3×Tg-AD mice were nasally administered with NGF (NGF, 40 μg/mouse), insulin (INS, 0.125 IU/mouse) or vehicle (veh) by bilateral nasal drop (2.5 μl/nostril) and sacrificed 30 min later.