Effects Of Exercise On Learning And Memory Of Rats And On CaMKIV, CREB And BDNF In Hippocampus

It has shown that proper physical exercise may enhance not only physical health but also mental health,and promote the cognitive function and the development of personality,particularly including the advanced form of learning and memory. Exercise is helpful for the neuron proliferation,growth and differentiation in animal hippocampus which is closely related to learning and memory,facilitates to induce long-term potentiation(LTP) and enhances synaptic plasticity.It has proved that exercise improves the ability of spatial memory and passive avoidance memory of animal.But this mechanism of exercise-induced improvement of learning and memory has needed further study.With the development of molecular biology,we have known some genes associated with learning and memory and their functions.In these genes,cAMP response element binding protein(CREB) is a kind of important nuclear transcription factor,which has extensive biological functions including adjusting learning and memory,and plays a "switch" role in regulating learning and memory in gene transcription level.As a upstream gene,Calmodulin-dependent protein kinase IV(CaMKIV)plays an important role in the phosphorylation of CREB. Brain-derived neurotrophic factor(BDNF) has wide roles in central nervous system and is closely implicated in the exercise-induced improvement of learning and memory.This study will select the signal pathway of CaMKIV-CREB-BDNF to study the effects of 8-week aerobic treadmill training on the gene express of CaMKW, CREB and BDNF,and discuss the interactions and relations of CaMKIV,CREB and BDNF during the course of exercise-improving learning and memory.Materials & methods:Healthy male Spargue-Dawley rats are selected and assigned randomly into two groups:controlled(C,n=10),trained(T,n=10).The rats of trained group take part in running training for 8 weeks.All groups participate in the Morris Water Maze test for 6 days during the 8th week.After 24 hours of the last running training,T group and C group are killed by decapitation and hippocampuses are quickly taken out.The expression level of CaMKIV mRNA,CREB mRNA,BDNF mRNA in Hippocampus of all rats are inspected by real-time fluorescence quantitative PCR.The results are as follows: (1) 8-week aerobic treadmill training can enhance the abilities of learning and memory of T group of rats in MWM.(2) 8-week aerobic treadmill training can significantly up-regulate the expression of CaMKIV mRNA(37.5%),CREB mRNA(28.8%),BDNF mRNA(42.3%) in different exent.Conclusion:8-week aerobic treadmill training can improve the abilities of learning and memory of rats and up-regulate the expression level of CaMKIV mRNA,CREB mRNA,BDNF mRNA.So the mechanism by which the long-term and suitable exercise enhances learning and memory of rats may have close relation to the increase of the expression level of CaMKIV mRNA,CREB mRNA,BDNF mRNA.The signal path of CaMKIV-CREB-BDNF may be one of mechanisms of enhancing learning and memory.