Chronic Running Exercise Promotes Spatial Learning and Memory in Rats

BACKGROUND: Exercise has beneficial effects on brain function, and induces constructional changes in different parts of brain, synapses, hippocampal neurogenesis, neuronal activity, synaptic structure, synthesis and enhancement of neurotransmitters as well as learning and spatial memory. METHODS: In this study, 40 rats were divided in four groups according to their exercise level: control, 40, 30, and 8 days exercise. Spatial learning and memory was recorded in the Morris water maze during 8 days. Latency and the length of swim path were used to evaluate spatial learning and long-term memory (the percent of the time). The data was analyzed by using the analysis of variance (ANOVA) test. FINDINGS: Significant increase was found in total means of eight day long-term memory among three exercise groups in comparison with control group (p<0.05). Comparing the results between exercise and control groups, we found a significant decrease in total means of eight-days path length, in 40 days-exercise (p<0.01) and 30 days-exercise (p<0.05), and latency in 40 days-exercise groups (p<0.05). CONCLUSION: Results of this study confirmed the hypothesis that longer period of acute exercise would have progressive and improving effects on learning and spatial memory. Long-term memory is more affected by simultaneous exercise rather than periodic or previous exercise. This should be related to the fact that different periods of exercise can influence various pathways in cells and might have different impacts on synapses in hippocampus; for instance short-term exercise increased mRNAs synapsin I, long-term exercise increased MAPK type 1 and 2, neurotransmitter and vesicular transferring protein. KEY WORDS: Spatial memory, hippocampus, Morris water maze, long-term memory