do Nascimento Silva Josiane, Rodrigues Bianca Andrade, Kawamoto Elisa Mitiko
Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, São Paulo, SP, 05508-000, Brazil.
Brain Struct Funct. 2024 Dec 17;230(1):7. doi: 10.1007/s00429-024-02878-1.
Serotonin (5-HT) is an important neurotransmitter for cognition and neurogenesis in the dentate gyrus (DG), which occurs via movement stimulation such as physical activity. Brain 5-HT function changes secondary to aging require further investigation. We evaluated whether aged animals would present changes in the number of 5-HT neurons in regions such as the dorsal (DRN) and median (MRN) raphe nuclei and possible changes in the rate of cellular activation in the DG in response to acute running, as a reduction in 5-HT neurons could contribute to a decline in neuronal activation in the DG in response to physical activity in aged mice. This study was conducted on adult (3 months old) and aged (19 months old) male and female mice. Immunohistochemistry, microscopic analysis, and treadmill-running tests were also performed. The data revealed that in aged mice, a reduction in the number of 5-HT neurons in the DRN and MRN of male and female mice was observed. The reduction in the DRN was greater in females. Furthermore, aged animals demonstrate a lower rate of c-Fos labeling in the DG when stimulated by physical exercise. These data indicate that aging may be associated with a reduction in the number of 5-HT neurons in the DRN and MRN, which may lead to a decline in 5-HT availability in the target regions, including the DG. The reduced c-Fos expression in the DG after running in aged mice indicates a decreased response to physical activity, which is potentially linked to serotonergic deficits.
血清素（5-羟色胺，5-HT）是齿状回（DG）中认知和神经发生的重要神经递质，其通过诸如体育活动等运动刺激产生。衰老继发的脑5-HT功能变化尚需进一步研究。我们评估了老年动物背侧中缝核（DRN）和中缝正中核（MRN）等区域的5-HT神经元数量是否会发生变化，以及急性跑步后DG中细胞激活率是否会有变化，因为5-HT神经元数量减少可能导致老年小鼠DG中神经元对体育活动的激活能力下降。本研究以成年（3月龄）和老年（19月龄）雄性及雌性小鼠为对象。还进行了免疫组织化学、显微镜分析和跑步机跑步测试。数据显示，在老年小鼠中，观察到雄性和雌性小鼠DRN和MRN中的5-HT神经元数量减少。雌性小鼠DRN中的减少更为明显。此外，老年动物在接受体育锻炼刺激时，DG中的c-Fos标记率较低。这些数据表明，衰老可能与DRN和MRN中5-HT神经元数量减少有关，这可能导致包括DG在内的靶区域中5-HT可用性下降。老年小鼠跑步后DG中c-Fos表达降低表明对体育活动的反应减弱，这可能与血清素能缺陷有关。
