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Effects of chronic treadmill running on neurogenesis in the dentate gyrus of the hippocampus of adult rat. Brain Res

Department of Sport and Exercise Sciences, Graduate School of Sport Sciences, Osaka University of Health and Sport Sciences, Asashirodai1-1, Kumatori-cho, Sennan-gun, Osaka 590-0496, Japan.
Brain Research (Impact Factor: 2.83). 09/2006; 1104(1):64-72. DOI: 10.1016/j.brainres.2006.05.066
Source: PubMed

ABSTRACT Proliferating astrocytes and proliferating neuroblasts have been observed in the subgranular zone (SGZ) of the dentate gyrus (DG) in the hippocampus of adult rats under normal conditions. However, whether these proliferating cells are stimulated by running has not been determined. Using immunohistochemical techniques, we examined the effects of chronic treadmill running on proliferating astrocytes (PCNA+/GFAP+ cells), proliferating neuroblasts (PCNA+/DCX+ cells) and newly generated postmitotic neurons (DCX+/NeuN+ cells) in the DG of the hippocampus of adult rats and also characterized the morphological features of PCNA+/GFAP+ cells and PCNA+/DCX+ cells. PCNA+/GFAP+ cells with few processes and PCNA+/DCX+ cells without long processes were detected in the SGZ, and we determined that these are morphological features of the astrocytes and neuroblasts with proliferative ability. Chronic treadmill running (at a speed of 22 m/min, 30 min/days for 7 days) significantly increased the numbers of PCNA+/GFAP+ cells and DCX+/NeuN+ cells, and the number of PCNA+/DCX+ cells tended to increase by chronic treadmill running. These results indicate that chronic treadmill running stimulates the proliferation of astrocytes in the SGZ. Furthermore, the present study indicates that chronic treadmill running increases DCX+/NeuN+ cells that are detected in a transient stage during the neuronal maturation process. These events may be the cellular basis mediating both running-induced increases of new neurons in the DG of the hippocampus and running-induced improvement of learning and memory functions of adult rats.

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    • "In this context, Huang et al. (2013) suggested that exercise-induced cognitive improvement of middle-aged rats might be associated with an increase on the capillaries density in the rat cortex. The exercise-induced astrogliosis here observed in the sham group is supported by previous studies which demonstrated an increase in astrocytic activation and proliferation of GFAP positive cells, in the subgranular zone of the hippocampus, in healthy exercised rats (Uda et al., 2006; Li et al., 2005; Saur et al., 2014). Besides, our findings are in accordance with Valentim et al. (1999) that observed an early and late increase in both immunocontent and GFAP phosphorylation rate in the hippocampus from ischemic rats, Fig. 3 "
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    • "For instance, Kim et al. (2003), in a study that evaluated the impact of different exercise protocols on cell proliferation , found that they may have markedly different effects on neuronal function. The mechanisms through which exercise facilitates spatial memory are still unclear, but it is believed that certain factors may be involved, such as the production of BDNF (Griffin et al., 2009; Ferreira et al., 2011), potentiation of glutamatergic transmission (O'Callaghan et al., 2007; Liu et al., 2011) and neurogenesis (Uda et al., 2006). Regarding the endocannabinoid system, our study shows that the exercise-induced spatial memory improvement was prevented by simultaneous blockade of the CB 1 receptor with AM251. "
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    • "Furthermore, it has been theorized that forced exercise is a better model for humans, as it is performed for a restricted period of time, and forced running also models most humans' attitude toward exercise; whereas voluntary exercise would more accurately model athletic individuals that would choose to engage in prolonged physical activity (i.e. endurance athletes) [24] [25]. In light of this, forced daily exercise is a better model for studying the effects of exercise in recovering addicted subjects who are being encouraged to run as part of the activities of a substance abuse treatment program. "
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