Effect of amphetamine on learning ability and GFAP-positive cells structure of hippocampal formation in rats

Objective To explore the effect of amphetamine on learning ability and GFAP-positive cells structure and subcell structure in hippocampal formation in rats.Methods The male SD rats were injected amphetamine into muscle as model of drug abuse.The ability of spatial discriminative learning was assessed by water maze.Immunohistochemical method was used to identify the changes in astrocytes morphology and change of GFAP expression;and ultrastructure of GFAP-positive cells was observed with electronic microscopy.Results The results from the spatial discriminative learning ability:From day 1 to 14,the mean running time and the mean latency in the amphetamine group was shorter than that of the saline group (P0.05),from day 14 to 28,the correct ratio in the amphetamine group was much lower,and was further lower from day 29 to 42,the mean running time was increased compared with the saline group (P 0.05);The result of immunohistochemical method:Astrocytes are mainly distributed in the polymorphic layer and molecular layer of the hippocampus and dentate gyrus in the swimming group.The distribution pattern in saline group was the same as that of the swimming group,but the number of astrocytes were increased in different subfield of hippocampus (P0.05),and the processes of astrocytes were longer and larger,with more branches in saline group.There was also an increase in the saline group (P0.05).The number of astrocytes in the amphetamine group rats were significantly increased compared with the saline group or the swimming group (P0.05),and the processes of astrocytes were more longer and larger,with more branches compared with the saline group.The result of ultrastructure by electronic microscope:Hyperplasia and hypertrophy of astrocytes were found,and the degenerative astrocytes were also found.Conclusion Our results suggested that amphetamine can cause proliferation and damage of astrocytes in rat hippocampal formation.