Santiago Henrique P, Leite Laura H R, Lima Paulo Marcelo A, Rodovalho Gisele V, Szawka Raphael E, Coimbra Cândido C
Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.
Clin Exp Pharmacol Physiol. 2016 Jan;43(1):116-24. doi: 10.1111/1440-1681.12507.
The effects of physical training on hypothalamic activation after exercise and their relationship with heat dissipation were investigated. Following 8 weeks of physical training, trained (TR, n = 9) and untrained (UN, n = 8) Wistar rats were submitted to a regimen of incremental running until fatigue while body and tail temperatures were recorded. After exercise, hypothalamic c-Fos immunohistochemistry analysis was performed. The workload, body-heating rate, heat storage and body temperature threshold for cutaneous vasodilation were calculated. Physical training increased the number of c-Fos immunoreactive neurons in the paraventricular, medial preoptic and median preoptic nucleus by 112%, 90% and 65% (P < 0.01) after exercise, respectively. In these hypothalamic regions, increased neuronal activation was directly associated with the increased workload performed by TR animals (P < 0.01). Moreover, a reduction of 0.6°C in the body temperature threshold for cutaneous vasodilation was shown by TR animals (P < 0.01). This reduction was possibly responsible for the lower body-heating rate (0.019 ± 0.002°C/min, TR vs 0.030 ± 0.005°C/min, UN, P < 0.05) and the decreased ratio between heat storage and the workload performed by TR animals (18.18 ± 1.65 cal/kg, TR vs 31.38 ± 5.35 cal/kg, UN, P < 0.05). The data indicate that physical training enhances hypothalamic neuronal activation during exercise. This enhancement is the central adaptation relating to better physical performance, characterized by a lower ratio of heat stored to workload performed, due to improved heat dissipation.
研究了体育锻炼对运动后下丘脑激活的影响及其与散热的关系。经过8周的体育锻炼后，将受过训练的（TR，n = 9）和未受过训练的（UN，n = 8）Wistar大鼠进行递增跑步直至疲劳，同时记录其体温和尾温。运动后，进行下丘脑c-Fos免疫组织化学分析。计算工作量、身体加热速率、蓄热和皮肤血管舒张的体温阈值。体育锻炼使运动后室旁核、视前内侧核和视前正中核中c-Fos免疫反应性神经元的数量分别增加了112%、90%和65%（P < 0.01）。在这些下丘脑区域，神经元激活的增加与TR组动物完成的工作量增加直接相关（P < 0.01）。此外，TR组动物的皮肤血管舒张体温阈值降低了0.6°C（P < 0.01）。这种降低可能是导致TR组动物较低的身体加热速率（0.019±0.002°C/分钟，TR组 vs 0.030±0.005°C/分钟，UN组，P < 0.05）以及TR组动物蓄热与完成工作量之间的比例降低（18.18±1.65卡路里/千克，TR组 vs 31.38±5.35卡路里/千克，UN组，P < 0.05）的原因。数据表明，体育锻炼可增强运动过程中下丘脑神经元的激活。这种增强是与更好的身体表现相关的中枢适应性变化，其特征是由于散热改善，蓄热与完成工作量的比例较低。
