Objective To observe the expression of ? APP and SS in the hippocampus of the rat mode ls with the deficits of learning and memory function, and investigate its mechanism.Methods Using immunohistochemistry (IHC), we detected the expressions of ? amyloid precursorprotein(? APP) and somatostatin(SS) in the hippocampus of the rat brains,using HE staining method, we observed the shapes and structures of pyramidal cell layer neurons in hippocampus of the rats in the experimental group and the controls.Results The learning and memory functions were lower significantly in the experimental group than in the controls ( P