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Objective To explore the effect of the treadmill exercise intervention on the behavior function and the concentration of dopamine in the striatum of the rat model of Parkinson's disease (PD).Methods Healthy male Sprague-Dawley rats were randomly divided into a sham operation quiet (Control) group,sham-operation+Exercise (Control + Ex) group,6-hydroxydopamine (6-OHDA) quiet (PD) group,and 6-OHDA+Exercise (PD + Ex) group.PD and PD + Ex groups were injected 6-OH-DA into the right medial forebrain bundle to establish the unilateral PD rat model,while the sham operation groups were injected the same amount of physiological saline at the same site.On the 7th days after modeling,the rats were subcutaneously injected Apo morphine for rotational behavior test to exclude those not meeting the requirements for the PD model.One week after the operation,the exercise group started treadmill training at the speed of 11 m/min,30 min/day and 5 days/week,for a total of four weeks.The locomotor activity of PD rats was evaluated using the open field test.The DA concentration in striatum was detected using micro dialysis high performance liquid chromatography and electrochemistry.The expression of tyrosine hydroxylase positive fiber in the striatum was assessed using the immunohistochemistry.Results Compared with the Control group,significant decrease was observed in the moving distance of PD and PD + Ex groups (P＜0.01),while significant increase was found of PD + Ex group compared with PD group after 3 and 4weeks of training (P＜0.01).Compared with the Control group,DA concentration in the striatal decreased significantly in PD and PD + Ex groups,but that of PD + Ex group increased significantly after 3 and 4weeks' training compared with the PD group (P＜0.01).Conclusion There is a highly positive correlation between the total moving distance and the DA concentration in the striatum of PD rats.The moving distance and the DA concentration both have changed "sequentially" with the prolongation of 6-OHDA and exercise intervention.The exercise intervention can reduce the DA loss of the striatum and improve the locomotor function of PD rats.It is presumed that the mechanism may be related to the neuroprotective effect of exercise,which can reduce the damage of 6-OHDA neurotoxin to DA neurons and promote their survival.
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Objective To observe the local field potential activity of dorsomedial and dorsolater striatal (STR) neurons in rats with exercise-induced fatigue,so as to explore the regional characteristics of those neurons.Methods Thirty-six male Wistar rats were randomly divided into a control group(CG),a single fatigue group(SFG)and a repeated fatigue group(RFG),each of 12.The exercise-induced fatigue model was established according to a load-increasing treadmill running protocol.The CG did not do any treadmill running,SFG finished one-time exhaustive exercise while the RFG repeated exhaustive exercise 6 times.The extracellular glass microelectrode technique was used to record the spontaneous firing of dorsomedial(n=6)and dorsolateral(n=6)STR neurons in vivo to observe the discharging frequency,characteristics and types.Results (1)Spontaneous firing frequencies of striatal neurons in SFG were significantly higher than those of CG(P＜0.01),while those of RFG were significantly lower than SFG.(2) After repeated fatigues,there were significant decreases in the irregular firing pattern and significant increase in the explosive firing of striatal neurons compared with CG(P＜0.05).(3)After the single fatigue and repeated fatigue,the discharging frequency of dorsomedial medium spiny-like neurons increased significantly(P＜0.05),and that after repeated fatigue significantly higher than that of the dorsolateral(P＜0.01).The discharge frequency of the dorsomedial and dorsolateral fast-spiking neurons decreased significantly after repeated fatigues.The discharge frequency of dorsolateral large aspiny-like neurons of RFG was significantly higher than SFG,while that of the latter was significantly lower than CG(P＜0.05).Conclusions (1)Striatal neurons mediate exercise-induced fatigue and present regional characteristics,which might be due to dorsomedial and dorsolateral striatal neurons receiving different types of projection neurons.(2) Striatal fast-spiking neurons may play an important role in mediating the exercise-induced fatigue.
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Objective To explore the effects of excise-induced fatigue on the microloop plasticity of prefrontal cortex through observing the expression of parvalbumin positive neurons in prefrontal cortexes of rats induced by exhaustive exercise,so as to find out the possible mechanism of the central regulation of exercise-induced fatigue by measuring the expression of NMDAR2B receptors.Methods Thirty-six Wistar rats were randomly divided into an exhausted group (E),a repeated exhaustion group (RE) and a control group (CG),each of 12.For group E,the adjusted Bedford incremental load of treadmill exercise program was employed:the initial treadmill speed was 8.2 m/min,lasting for 15 minutes,then increased to 15 m/min for another 15 minutes,and finally increased to 20 m/min till exhaustion.For RE group,they were given continuous treadmill exercises to exhaustion for consecutive 7 days.The immunofluorescence technique was used to observe the expression of PV+ interneurons after exhausted treadmill running.The Western blotting technique was used to determine the expression of NMDAR2B in the tissue of the prefrontal cortex.Results After the exhausted treadmill running,the expression of PV+ interneurons in the prefrontal cortexes of both E and RE groups increased significantly compared with the control group(P＜0.01).The immunofluorescence results indicated that NMDAR2B positive neurons were seen in group E,but not obviously in group CG and RE.The Western blotting showed that compared with CG group the protein expression of NMDAR2B in prefrontal cortexes of group E was relatively high,and that of group RE was relatively low,but without significant difference (P＞0.05).The running distance and prefrontal cortex NMDAR2B expression were found negatively correlated (P＜ 0.01).Conclusions Exhaustive exercises have an impact on the plasticity in rats' prefrontal cortex neural network through regulating the local loop of PV positive neurons.This plasticity of the prefrontal cortex is involved in the regulation of central fatigue.The present study might provide morphological basis for the research of central mechanism of the exercise-induced fatigue.
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Objective:To observe the changes of 5-HT1B and D1DR expression in nucleus of SNr/GPi-VL-SMA pathway in pre and post-exhaustive exercise,and investigate the central mechanism of SNr/GPi-VL-SMA pathway modulating the occurrence and development of exercise-induced fatigue.Method:Twenty-four male Wistar rats were randomly divided into control group (CG),immediately after exhaustion group (EG),and 90min after recovery group (RG),each consists of 8 rats.The expression level of 5-HT1B and D1DR receptors in each group were observed with the immunohistochemistry technique.Result:Compared with CG,the positive cell area/scanning area value (R value) and the average optical density value (AOD value) of 5-HT1B receptor in SNr and GPi of the EG and RG rats both decreased significantly (P ＜ 0.05),while the R value and AOD value of D1DR both increased significantly(P＜ 0.05).The R value and AOD value of 5-HT1B receptor in VL of EG and RG rats increased significantly(P＜0.05,P＜0.01).In SMA,the R value and AOD value of 5-HT1B receptor of EG and RG rats increased significantly (P＜ 0.05),while,the R value and AOD value of D1DR receptor decreased significantly (P ＜ 0.05).Conclusion:Changes of 5-HT1B receptor and D1DR receptor expression in the nuclei of ‘SNr/GPi-VL-SMA'pathway caused the changes of the neurotransmitters release,thus affecting the excitability of the electrical activity of neurons,this might be one of the important ways for ‘SNr/GPi-VL-SMA'pathway modulating the exercise-induced fatigue and exercise performance.