Relationship Between Morphological Plasticity Of Hippocampal Formation And Receptor EphA5 During Spatial Learning And Memory In Rats

PurposeThe relationship between the morphology plasticity and the expression changes of receptor EphA5 ofthe hippocampal formation in rats obtaineing the abilities of spatial discriminative learning and memory werestudied.MethodsSD male rats were randomly divided into three groups: the model group, the swimming group and thecontrol group. The animals of the model group were trained with the water maze. The methods of Timm stainused to test the fibers sprouting in the hippocampal formation. With the method of immunohistochemistry theexpression difference of receptor EphA5 in hippocampal formation was tested.Then the positive EphA5immunostaining particles under the subcellular level were localized with immunoelectronic microscopicmetheod.The datas were analyzed by the software of SPSS 10.0 for windows.Results1. The average latent, the average running time and the correct ratio of all three quotas of the model ratsreached the standard on references after trained for 7 days with the water maze.2. The rats in the model group showed sprouting moss fibers at the polymorphic layer in their hippocampalCA3 subfield with Timm stain method. Furthermore, the extent of nervous fibers sprouting reached to apeak on the 14th training day.The rate of sprouting moss fibers in model group was 88.8%, rate ofswinmming group is 22.2%. In control group, no rats were found sprouting moss fibers at the polymorphiclaye.3 Compared with the swimming and control group, the gray scale of positive EphA5 immunostaining particlesin model rats showed a descent trend but the quantity of positive cells showed a increase one in everysubfields of hippocampus.But there was no significant difference between the swimming and controlgroup. In model group after trained for 14 days, the expression of receptor EphA5 was significantlyenhanced compared with the others.4 The positive EphA5 immunostaining particles under the subcellular level were localized at cell membraneand terminal of synapse by electronic microscopic metheod.Conclusions 1. The animal model of spatial discriminative learning and memory can be established trained with watermaze.2. The plasticity changes of nervous fibers took place in hippocampus structures of rats when they obtainedthe function of spatial discriminative learning and memory.3. There is a correlated relationship between the receptor EphA5 and sprouting nervous fibers inhippocampus structure.