Tarassova Olga, Jiang Yiwen, Wallin Helena, Jensen-Urstad Mats, Drca Nikola, Röja Julia, Pontén Marjan, Katz Abram, Nilsson Jonna, Ekblom Maria M, Moberg Marcus
Department of Physical Activity and Health, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden.
Department of Physiology, Nutrition, and Biomechanics, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden.
J Physiol. 2025 Apr 13. doi: 10.1113/JP288409.
Brain-derived neurotrophic factor (BDNF) is essential for neuroplasticity. Exercise can induce increases in forearm venous plasma and serum BDNF, often assumed to be indicative of release from the brain. We investigated the effects of exercise on circulating levels of mature BDNF (mBDNF) and its precursor proBDNF. Sixteen healthy, physically fit adults (20-40 years old) cycled for 20 min at 40, 60 and 80% of , separated by 30 min of rest. BDNF was analysed in blood samples from the brachial artery, internal jugular vein, femoral vein and antecubital vein. Brain/skeletal muscle exchange of BDNF, calculated as arterial-venous differences in BDNF multiplied by blood flow in the middle cerebral artery/common femoral artery, was measured simultaneously with blood sampling. Exercise intensity-dependent increases were observed in blood platelet count, forearm venous serum mBDNF and plasma proBDNF, but not in forearm venous plasma mBDNF. Brain release (or uptake) was not detected for either plasma mBDNF, serum mBDNF or plasma proBDNF. However, muscle uptake of plasma mBDNF and release of plasma proBDNF were observed after high-intensity exercise. Our findings demonstrate that exercise-dependent increases in serum mBDNF are not derived from the brain or the exercised skeletal muscle. Rather, the source of the increase appears to be the increase in platelets that are enriched with mBDNF. Furthermore, in physically fit adults, BDNF is not released from the brain into the bloodstream, after exercise, regardless of exercise intensity. Finally, changes in plasma proBDNF after exercise appear to be dependent on exercised skeletal muscle rather than brain release. KEY POINTS: Previously shown exercise-induced increases in forearm venous brain-derived neurotrophic factor (BDNF) are often assumed to be indicative of release from the brain. We investigated whether exercise-induced changes in forearm venous mature BDNF (mBDNF) and precursor proBDNF are paralleled by concomitant changes in BDNF exchange over the brain and skeletal muscle. We observed exercise intensity-dependent increases in platelet count, forearm venous serum mBDNF and plasma proBDNF, but not in forearm venous plasma mBDNF. We found muscle uptake of plasma mBDNF and release of plasma proBDNF after high-intensity exercise but no exercise intensity-dependent brain exchange of either plasma mBDNF, serum mBDNF or plasma proBDNF. Our findings suggest that acute exercise-induced increases in circulating serum mBDNF may be solely a result of increased platelet count, probably due to splenic platelet release; and that exercised skeletal muscle, and not the brain, responds to high-intensity exercise by releasing plasma proBDNF.
脑源性神经营养因子（BDNF）对神经可塑性至关重要。运动可诱导前臂静脉血浆和血清中BDNF升高，通常认为这表明其从大脑释放。我们研究了运动对成熟BDNF（mBDNF）及其前体proBDNF循环水平的影响。16名健康、体能良好的成年人（20 - 40岁）以最大摄氧量的40%、60%和80%进行20分钟的骑行，每次骑行间隔30分钟休息。对来自肱动脉、颈内静脉、股静脉和肘前静脉的血样进行BDNF分析。在采血的同时，测量BDNF的脑/骨骼肌交换，计算方法为BDNF的动静脉差值乘以大脑中动脉/股总动脉的血流量。观察到血小板计数、前臂静脉血清mBDNF和血浆proBDNF随运动强度增加而升高，但前臂静脉血浆mBDNF未升高。未检测到血浆mBDNF、血清mBDNF或血浆proBDNF的脑释放（或摄取）。然而，高强度运动后观察到肌肉对血浆mBDNF的摄取和血浆proBDNF的释放。我们的研究结果表明，运动引起的血清mBDNF升高并非来自大脑或运动的骨骼肌。相反，升高的来源似乎是富含mBDNF的血小板数量增加。此外，在体能良好的成年人中，运动后无论运动强度如何，BDNF都不会从大脑释放到血液中。最后，运动后血浆proBDNF的变化似乎取决于运动的骨骼肌而非大脑释放。要点：先前显示运动诱导的前臂静脉脑源性神经营养因子（BDNF）升高通常被认为表明其从大脑释放。我们研究了运动诱导的前臂静脉成熟BDNF（mBDNF）和前体proBDNF的变化是否与脑和骨骼肌中BDNF交换的相应变化平行。我们观察到血小板计数、前臂静脉血清mBDNF和血浆proBDNF随运动强度增加而升高，但前臂静脉血浆mBDNF未升高。我们发现高强度运动后肌肉对血浆mBDNF的摄取和血浆proBDNF的释放，但未发现血浆mBDNF、血清mBDNF或血浆proBDNF的运动强度依赖性脑交换。我们的研究结果表明，急性运动诱导的循环血清mBDNF升高可能仅仅是血小板计数增加的结果，可能是由于脾脏释放血小板；并且运动的骨骼肌而非大脑通过释放血浆proBDNF对高强度运动做出反应。
