Laboratory of Studies on the Purinergic System, Graduation Program in Biological Sciences/Biochemistry, Federal University of Rio Grande do Sul, Health and Basic Sciences Institute, Department of Biochemistry, Porto Alegre/RS 90035-003, Brazil.
Neuroscience. 2012 Oct 11;222:100-9. doi: 10.1016/j.neuroscience.2012.06.068. Epub 2012 Jul 13.
The participation of the brain-derived neurotrophic factor (BDNF) in the benefits of physical exercise on cognitive functions has been widely investigated. Different from voluntary exercise, the effects of treadmill running on memory and BDNF are still controversial. Importantly, the impact of the frequency of physical exercise on memory remains still unknown. In this study, young adult and middle-aged rats were submitted to 8 weeks of treadmill running at moderate intensity and divided into 4 groups of frequency: 0, 1, 3 and 7 days/week. Aversive and recognition memory were assessed as well as the immunocontent of proBDNF, BDNF and tyrosine kinase receptor type B (TrkB) in the hippocampus. Frequencies did not modify memory in young adult animals. The frequency of 1 day/week increased proBDNF and BDNF. All frequencies decreased TrkB immunocontent. Middle-aged animals presented memory impairment along with increased BDNF and downregulation of TrkB receptor. The frequency of 1day/week reversed age-related recognition memory impairment, but worsened the performance in the inhibitory avoidance task. The other frequencies rescued aversive memory, but not recognition memory. None of frequencies altered the age-related increase in the BDNF. Seven days/week decreased proBDNF and there was a trend toward increase in the TrkB by the frequency of 1 day/week. These results support that the frequency and intensity of exercise have a profound impact on cognitive functions mainly in elderly. Thus, the effects of physical exercise on behavior and brain functions should take into account the frequency and intensity.
脑源性神经营养因子（BDNF）参与了体育锻炼对认知功能的益处，这已经得到了广泛的研究。与自愿运动不同，跑步机跑步对记忆和 BDNF 的影响仍存在争议。重要的是，运动频率对记忆的影响仍然未知。在这项研究中，年轻成年和中年大鼠接受了 8 周的中等强度跑步机跑步，并分为 4 个频率组：0、1、3 和 7 天/周。评估了厌恶和识别记忆，以及海马体中 proBDNF、BDNF 和酪氨酸激酶受体 B（TrkB）的免疫含量。在年轻成年动物中，频率不改变记忆。1 天/周的频率增加了 proBDNF 和 BDNF。所有频率都降低了 TrkB 的免疫含量。中年动物表现出记忆障碍，同时 BDNF 增加，TrkB 受体下调。1 天/周的频率逆转了与年龄相关的识别记忆障碍，但恶化了抑制回避任务的表现。其他频率挽救了厌恶记忆，但没有挽救识别记忆。没有频率改变与年龄相关的 BDNF 增加。1 天/周的频率降低了 proBDNF，而 7 天/周的频率则有增加 TrkB 的趋势。这些结果支持运动的频率和强度对认知功能有深远的影响，主要是在老年人中。因此，体育锻炼对行为和大脑功能的影响应该考虑到频率和强度。
