Studies on the mechanisms of manifestation of central fatigue

我们之前的研究表明，当受到各种因素（包括运动）的压力时，大脑中转化生长因子- β的浓度会增加，从而引发疲劳感。在本研究中，我们阐明了以下几点。tgf - β对大脑活动的影响。(1) TGF- β对大鼠脑电图的影响TGF注入大鼠脑后，α波功率百分比降低，θ波功率百分比升高。这些变化与运动后脑电图的变化相似。(2) tgf - β对大鼠脑内神经递质周转率的影响。TGF注入大鼠脑后，髓质和脑桥内血清素（5-HT）、多巴胺（DA）、去甲肾上腺素（NA）的周转率升高。间脑DA和NA均升高。细胞内5-HT和NA升高。这些变化部分类似于锻炼。(3)多给药tgf - β对中枢神经系统影响的神经化学研究通过微透析观察到海马和下丘脑DA细胞外5-HT浓度升高，下丘脑5-HT浓度降低。(4)脑组织tgf - β受体表达的组织化学研究。原位杂交法在海马和脑室中显示tgf - β受体mrna的表达。(1) tgf - β对大鼠呼吸交换率（PER）的影响中央给药可降低大鼠的RER，增加脂肪酸氧化素的比例。(2)脑内给药tgf - β对大鼠体温和心率的影响。中央给药tgf - β对大鼠体温和心率无显著影响。(3) tgf - β对甜味偏好的影响通过将tgf - β注入大脑，小鼠对甜味的偏好增加，如运动后所见。少

Previous studies of ours showed transforming growth factor-beta which increased in the concentration in the brain when stressed by various factors (including exercise), elicited the feeling of fatigue. In this study, we elucidated as follows.I. Effects of TGF-beta on brain activities.(1)Effects of TGF-beta on rat electroencephalogram (EEG)By administration of TGF into the rat brain, the power percentage of alpha wave was decreased, whereas that of theta wave was increase. These changes were as similar as the changes of EEG after exercise.(2)Changes of turnover rate of neurotransmitters by administration of TGF-beta into rat brain.By administration of TGF into rat brain, the increases in turnover rate of serotonin (5-HT), dopamine (DA), and noradrenaline (NA) were observed in medulla and pons. In diencephalon the increases of DA and NA were observed. In strintum 5-HT and NA were increased. These changes were partially similar as that of exercise.(3)Neurochemical studies on the effect of … More TGF-beta administration on central nervous systemBy microdialysis the increases in the extracellular concentration of 5-HT in hippocampus and that of DA in hypothalamus, and decrease in that of 5-HT in hypothalamus were observed.(4)Histochemical studies on the expression of TGF-beta receptors in brainThe expression of mRNAs of TGF-beta receptors were showed in hippocampus and ventricles by in situ hybridization.II. Effects of TGF-beta administered into brain on peripheral tissues(1)Effects of TGF-beta on rat respiratory exchange ratio (PER)The RER of rats were decreased and the proportion of fatty acid oxidatjon were increased by central administration of TGF-beta.(2)Effects of TGF-beta administration into brain on body temperature and heart beat rate of rats.There was no significant change in the body temperature and heart beat rate of rats by central administration of TGF-beta.(3)Effects of TGF-beta on preferences for sweet tasteBy administration of TGF-beta into the brain, the preferences for sweet tastes were increased in mice, as seen after exercise. Less