Abstract: Objective To observe the effect of Sinisan on the learning and memorial ability and the expression of synaptohydin in the hippocampus of exercise-fatigue rats. Methods Rats were made into the fatigue model by Exhaustive Swimming. Learning and memorial ability of the rats were observed by moving-back with current stimulation experiment; expression of synaptohydin protein in hippocampus of exercise-fatigue rats treated with Sinisan for 10 days were detected by immunohistochemistry technique and compared to control group and model group.Results The moving-back time and the error times of the exercise-fatigue rats as follows: model group(73.00±61.96) s/(1.67±1.15), control group(144.25±57.14) s/(0.50±0.80)，Sinisan group (166.17±47.92) s/(0.38±0.49). Comparison of mean optical density of synaptohydin protein in hippocampus of rats in different groups as follows: control group (0.2636±0.10654) and Sinisan group (0.2555±0.163380) were higher than the model group (0.0474±0.1837)(P<0.05). The synaptohydin staining Results showed that synaptohydin-positive granules around the neuron in hippocampus of rats in control group were the darkest and densest, the Sinisan group were darker than the model group rats.Conclusion Sinisan could improve the learning and memorial ability and increase the synaptohydin protein in the hippocampus of the exercise-fatigue rats.

Key words: exercise-fatigue, hippocampus, synaptohydin