Skeletal muscle fibres of untrained animals experience a stress response following exercise. This study was aimed at investigating whether chronic exercise modulates stress proteins of 70 kDa (HSP70s) in skeletal muscle. In the soleus muscle of Wistar rats, adherence to an incremental programme of treadmill running (IPTR) of 3 months duration up-regulated the levels of the beta-subunit of the mitochondrial F1-ATPase and those of HSP72, GRP75 and GRP78. Neither beta-F1-ATPase nor sarcoplasmic reticulum Ca2+-ATPase levels changed with training in the extensor digitorum longus (EDL) muscle. However, HSP70s increased during training. In soleus muscle slices of animals sacrificed 3 days after completing the IPTR, HSP72 and GRP75 were synthesized at lower rates than in sedentary animals while the GRP78 synthesis rate increased. Trained, rested animals also experienced a stress response following acute exercise of lower intensity than that of the actual training sessions. The data suggest that up-regulation of HSP70s by chronic exercise depends upon continued physical activity. Furthermore, the inverse correlation between levels and rates of synthesis of HSP72 during rest periods suggests the operation of a feedback regulatory loop aimed at reestablishing the threshold levels characteristic of unstressed fibres.

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Dietary reconstruction is used to make inferences about the subsistence strategies of ancient human populations, but it may also serve as a proxy to characterise their diverse cultural and technological manifestations. Dental microwear and stable isotope analyses have been shown to be successful techniques for paleodietary reconstruction of ancient populations but, despite yielding complementary dietary information, these techniques have rarely been combined within the same study. Here we present for the first time a comprehensive approach to interpreting ancient lifeways through the results of buccal and occlusal microwear, and δ13C and δ15N isotope analyses applied to the same individuals of prehistoric populations of Hungary from the Middle Neolithic to the Late Bronze Age periods. This study aimed to (a) assess if the combination of techniques yields a more precise assessment of past dietary and subsistence practices, and (b) contribute to our understanding of the dietary patterns of the prehistoric Hungarian populations. Overall, no correlations between microwear and δ13C and δ15N isotope variables were observed, except for a relationship between nitrogen and the vertical and horizontal index. However, we found that diachronic differences are influenced by the variation within the period. Particularly, we found differences in microwear and isotope variables between Middle Neolithic sites, indicating that there were different dietary practices among those populations. Additionally, microwear results suggest no changes in the abrasiveness of the diet, neither food processing methods, despite higher C4 plant resource consumption shown by carbon isotopic signal. Thus, we demonstrate that the integration of dental microwear and carbon and nitrogen stable isotope methodologies can provide complementary information for making inferences about paleodietary habits.