Research On The Mechanisms Of Electrophysiological Influnce Learning And Memory Of Different Exercise Load In Rat

Objective: Learning and memory is one of the important functions of thebrain network, which is done by the synergy of different types of neurons. Manystudies have indicated that as an important institution of learning and memory inthe brain, hippocampal can impair the spatial learning and memory, when it wasdamaged. However, the impact of exercise on learning and memory has longbeen reported, but its mechanism has been inconclusive. With the developmentand application of new technologies and neurosciencein recent years,neurobiology research has been breakthrough in the field of different levels ofcellular, subcellular, molecules and genes. Used by proven technologies,Weexplore the central nervous systemeffects mechanism and make a deeperunderstanding of the nature of the exercise.The local field potentials in hippocampal CA1region theta rhythm and long-term potentiation (LTP) areclosely related to learning and memory. Long-term changes by aerobic exerciseon hippocampal theta rhythm is rarely reported. This study observed the effectsof different load exercise on rat hippocampal theta rhythm, and explore theeffect of different load exercise on the mechanism of learning and memory andbrain function.Subjects and Methods: Male Wistar rats, weighing220±20g, wereprovided by the Experimental Animal Center of Military Medical Sciences. Ratswere randomly divided into a control group (CG), low-intensity exercise group(LG) and high-intensity exercise group (HG), there are twelve rats in each group.According to component caged that six per cage were fed. The temperature offeeding room was keep23±2℃, the relative humidity was keep40%to60%,and the water consumped freely, natural circadian rhythm. Exercise model: therats were adopted three days adaptive training,the speed from3m/min to8m/minincreased and the time is10min each day. Then four weeks of formal trainingwas started. The speed of low load exercise group first from3m/min to8m/minfor10min, and then keep8m/min for30min,8m/min to3m/min for10min; Thespeed of high load exercise group first from3m/min to25m/min for10min, andthen keep25m/min for30min,25m/min to3m/min for10min. This motionmodel reference Cordova SD movement scheme. The control group did notintervention, but twice a mention tail grab, imitating aerobic exercise group andmouse movements into the treadmill on every day. After4weeks training, the behavior experiment were used to observe the changes of learning and memoryability; and the electrophysiological experiments were use to collectspontaneous and evoked electrical signals in the CA1region of rat hippocampusand to analyze the relationship between the changes of signal and learning andmemory ability.The results:1、The results of behavior experiment:1) The open-field test results showthat, LG rats from the central area of activity were significantly higher than CGand HG rats (P<0.05), HG rats from the central region of the activities weresignificantly decreased than CG rats (P<0.05);2)Y-maze alternation ofindependent experimental show that, the alternation of LG were significantlyhigher than CG and HG rats (P<0.05), and the alternation of HG weresignificantly dreased than CG rats (P<0.05);2、The results of Electrophysiological:1) The local field potential in vivoresults show that, the theta rhythms power of HG in the rat hippocampus CA1area were significantly higher than CG and LG rats (P<0.05, P<0.01); andthetheta rhythms power ofLGwere significantly lower than CG (P<0.05). But therewas no significant difference on the theta rhythms frequency of each group(P>0.05);2) The maintain of LTP results show that, different load exercise hadan affected on the E-LTP and L-LTP in hippocampus of rats. After HFS,compared with CG, the average slope of E-LTP of LGrats were significantlyhigher (P<0.05), and HG rats were significantly lower (P<0.05);There are no significant difference in LG and CG rats L-LTP test,(P>0.05), while the averageslope of L-LTP of HG rats were significantly than LG and CG rats (P<0.05,P<0.01).Conclusions:1、Low-load exercise may reduce the theta rhythm power in hippocampalCA1area of rats.2、High-load exercise may improve he theta rhythm power in hippocampalCA1area of rats.3、Low-load exercise can promote the induced of LTP in rat hippocampal，and improve the ability of learning and memory.4、High-loadexercise may inhibite the induced of LTP in rat hippocampal，and impair t the ability of learning and memory.