Supercompensação cerebral de glicogênio?

Embora não testado, é a hipótese de que, semelhante ao do músculo esquelético, ocorre supercompensação de glicogênio no cérebro após exercício exaustivo. Os dados mostram que o exercício exaustivo induz supercompensação do glicogênio não só nos músculos esqueléticos, mas também no cérebro. Além disso, observou-se que exercício induz os glicogênios basais no córtex e hipocampo, que estão envolvidos no controle motor e na função cognitiva. Isto sugere que, como os músculos esqueléticos, o cérebro se adapta metabolicamente, provavelmente para atender às demandas de energia crescentes de treinamento físico. 

Mais informações:

Brain glycogen supercompensation following exhaustive exercise

1. Takashi Matsui¹, 
2. Taro Ishikawa¹, 
3. Hitoshi Ito¹, 
4. Masahiro Okamoto¹,
5. Koshiro Inoue¹, 
6. Min-chul Lee¹, 
7. Takahiko Fujikawa², 
8. Yukio Ichitani³,
9. Kentaro Kawanaka⁴ and 
10. Hideaki Soya¹

+Author Affiliations

1. ¹Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8574, Japan²Laboratory of Molecular Prophylaxis and Pharmacology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, 3500-3 Suzuka, Minamitamagaki-cho, Suzuka, Mie 513-8670, Japan³Department of Behavioural Neuroscience, Institute of Psychology, University of Tsukuba Graduate School of Comprehensive Human Sciences, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8574, Japan⁴Department of Health and Nutrition, Niigata University of Health and Welfare, 1398 Shimami-cho, Kita-ku, Niigata, Niigata 950-3198, Japan

1. H. Soya: Laboratory of Exercise Biochemistry & Neuroendocrinology, Institute for Health and Sports Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8574, Ibaraki, Japan. Email: hsoya@taiiku.tsukuba.ac.jp

Abstract 

Brain glycogen localized in astrocytes, a critical energy source for neurons, decreases during prolonged exhaustive exercise with hypoglycaemia. However, it is uncertain whether exhaustive exercise induces glycogen supercompensation in the brain as in skeletal muscle. To explore this question, we exercised adult male rats to exhaustion at moderate intensity (20 m min⁻¹) by treadmill, and quantified glycogen levels in several brain loci and skeletal muscles using a high-power (10 kW) microwave irradiation method as a gold standard. Skeletal muscle glycogen was depleted by 82–90% with exhaustive exercise, and supercompensated by 43–46% at 24 h after exercise. Brain glycogen levels decreased by 50–64% with exhaustive exercise, and supercompensated by 29–63% (whole brain 46%, cortex 60%, hippocampus 33%, hypothalamus 29%, cerebellum 63% and brainstem 49%) at 6 h after exercise. The brain glycogen supercompensation rates after exercise positively correlated with their decrease rates during exercise. We also observed that cortical and hippocampal glycogen supercompensation were sustained until 24 h after exercise (long-lasting supercompensation), and their basal glycogen levels increased with 4 weeks of exercise training (60 min day⁻¹ at 20 m min⁻¹). These results support the hypothesis that, like the effect in skeletal muscles, glycogen supercompensation also occurs in the brain following exhaustive exercise, and the extent of supercompensation is dependent on that of glycogen decrease during exercise across brain regions. However, supercompensation in the brain preceded that of skeletal muscles. Further, the long-lasting supercompensation of the cortex and hippocampus is probably a prerequisite for their training adaptation (increased basal levels), probably to meet the increased energy demands of the brain in exercising animals.

• © 2011 The Authors. Journal compilation © 2011 The Physiological Society