Author(s): CUI, S., QIAO, D., Institution: BEIJING RESEARCH INSTITUTE OF SPORT SCIENCE, Country: CHINA, Abstract-ID: 759

INTRODUCTION:
The motor circuit composed of primary motor cortex and dorsal medial striatum which play an important role in the exercise induced fatigue. Whether exercise induced fatigue can induce the plastic changes in the glutamatergic system and synaptic proteins in motor cortex and dorsolateral striatum. Whether the exercise induced fatigue can altered plasticity-related protein NMDAR2B，CaMKII，pCaMKII，ERK expression in the motor cortex and dorsolateral.
METHODS:
Young adult male Wistar rats were divided into 3 groups: control group（CG）、single exhaustive exercise group (EG) and repeated exhaustive exercise group (REG). Incremental treadmill exercise was employed, The REG groups rats conducted 7 consecutive days of incremental load treadmill training. The initial treadmill speed was 8.2m/min, after 15min the speed increased to 15m/min, 15min later the speed improved upto 20m/min until fatigue. On testing day, rats performed either a single exhaustive (EG) or after 7 days exhaustive exercise (REG) or rested (CG) were then sacrificed and primary motor cortex and dorsolateral striatum dissected. Plasticity related proteins(NMDAR2B、CaMKII、pCaMKII and ERK)were detected by Western blotting analysis.
RESULTS:
The protein expression of NMDAR2B compared with group CG increased significantly of group EG and REG, There was no significant difference in the expression of CaMKII among the groups (P > 0.05).The pCaMKII expression of group REG significantly decreased compared with CG group(P<0.05). the ERK expression in the M1 area in RE group significantly decreased compared with CG group (P<0.01).The expression of NR2B in DLS area in REG group was significantly higher than the CG group(P<0.05),the EG group also higher than CG group, but had no significance(P>0.05); The expression of CaMKII had no significant difference between all the groups; The expression of pCaMKII in DLS was higher in EG group and REG group than that in CG group. But there was no significant difference (P > 0.05);The expression of ERK in DLS region of group EG and REG were increased compared with the group CG , REG group increased more obvious and it had significant difference compared with the group CG. (P < 0.05).
CONCLUSION:
As the increased of exercise induced fatigue, ERK expression in the primary motor cortex decreased, which may influence intrinsic excitability of motor cortex. It suggested integration ability in the primary motor cortex decreased. In contrast, ERK expression in the dorsolateral striatum increased which suggest the excitability in the dorsolateral striatum increased. CaMKII-ERK signaling in the motor cortex and dorsolateral striatum is a critical substrate for exercise induced fatigue. CONCLUSION:Single session exercise induced-fatigue does not altered plasticity-related protein expression in the M1, chronic exercise induced fatigue altered plasticity-related protein expression in M1 and DLS.