RESUMEN
Objective To observe the depositing regions of the cerebral neurons containing A?_ 42 neurons and to study the effects of ginkgo leaf extracts and dioyridamole injection on the memory,the deposition of A?_ 42 in the brain of Alzheimer's disease(AD) model rats induced by aluminium chloride(AlCl_3).Methods The experimental AD model of rats was established by 30% AlCl_3.The rats of treatment group received ginkgo leaf extracts and dioyridamole injection for consecutive six months.Latent period and the intensity of electric shock was evaluated by a passive-avoidence test before and after administration respectively.The morphology and the number of A?_ 42 neurons of the model rats brain by light microscope observation as well as immnohistochemistry.Results (1)After treatment,latent period of the rats prolonged and the intensity of electric shock reduced as compared with AlCl_3 group.(2)The depositing regions of A?_ 42 were found mainly in pyramidal cell layer of CA_1 hippocampus formation and polymorphical cell layer of dentate gyrus,external main stratum of entorhinal region and Ⅲ,Ⅵ,Ⅴ cell layer of cortex(parietal,temporal).The color of A?_ 42 positive substance was brown or brown yellow in the cytoplasm and its dendrites or branches.Significant reducing of A?_ 42 neurons occurred in treatment group(hippocampus P0.05).Conclusion Ginkgo leaf extracts and dioyridamole injection can improve the AD model rats ability of learn and memorizing,which mechanisms are achived by preventing A? from depositing and clearing deposited A?.