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The improvement of exercise performance by physical training is related to increased hypothalamic neuronal activation
Author(s) -
Santiago Henrique P,
Leite Laura HR,
Lima Paulo Marcelo A,
Rodovalho Gisele V,
Szawka Raphael E,
Coimbra Cândido C
Publication year - 2016
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/1440-1681.12507
Subject(s) - endocrinology , hyperthermia , medicine , median preoptic nucleus , chemistry , physical exercise , hypothalamus , subfornical organ , blood pressure , renin–angiotensin system
Summary 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.