Exercise is the most recommended non-pharmacological intervention to improve neurocognitive functions under physiological and pathological conditions. However, it remains to be elucidated concerning the influence and the underlying neurological molecular mechanism of different exercise intensity on cognitive function. In this study, we aimed to explore the effects of exercise intensity on spatial learning and memory, as well as the regulation of brain-derived neurotrophic factor (BDNF)/p-CREB/NMDAR signal. In the research, low-intensity consecutive treadmill (LICT) and high-intensity consecutive treadmill (HICT) were implied to rats for 8 weeks. We found that the performances in the Morris water maze were improved in the LICT group, while reduced in the HICT group as compared with the sedentary rats. Moreover, the expression of BDNF mRNA, phosphorylation cAMP-response-element binding protein (p-CREB), mature BDNF (mBDNF), tropomyosin receptor kinase B (TrkB), tissue plasminogen activator (t-PA), and NR2B proteins was increased, whereas the expression of precursor BDNF (proBDNF) and pan-neurotrophin receptor 75 (p75^NTR) proteins was decreased in the hippocampus of LICT group compared with the sedentary rats. On the contrary, the expression of proteins and mRNA aforementioned in the LICT group showed a reversed tendency in the hippocampus of HICT rats. These findings suggest that the consecutive low-intensity exercise and high-intensity exercise exert different effects on spatial learning and memory by oppositely regulating the mutual stimulation of p-CREB and BDNF mRNA feedback loop, as well as the t-PA/BDNF/NMDAR which is the post-translation cascades of BDNF signaling.

运动是最推荐的非药物干预，以改善生理和病理条件下的神经认知功能。然而，不同运动强度对认知功能的影响及其潜在的神经学分子机制仍有待阐明。本研究旨在探讨运动强度对空间学习记忆的影响，以及脑源性神经营养因子（BDNF）/p-CREB/NMDAR信号的调控。在研究中，低强度连续跑步机 (LICT) 和高强度连续跑步机 (HICT) 被暗示给大鼠 8 周。我们发现，与久坐不动的大鼠相比，LICT 组的 Morris 水迷宫的表现有所改善，而 HICT 组的表现则有所降低。此外，BDNF mRNA 的表达，与久坐大鼠相比，LICT 组海马中的^NTR ) 蛋白减少。相反，LICT组上述蛋白和mRNA的表达在HICT大鼠海马中呈逆转趋势。这些研究结果表明，连续低强度运动和高强度运动通过反向调节p-CREB和BDNF mRNA反馈回路以及t-PA/BDNF/NMDAR的相互刺激，对空间学习记忆产生不同的影响。这是 BDNF 信号的翻译后级联。