Enhanced angiogenesis, or capillary growth, has a prominent role among the various beneficial effects of exercise training
on the myocardium. The aim of the present study is to assess if training-induced increases in capillarity and vascularization
persist after 4 weeks of detraining. Adult male rats were trained to run on a treadmill for 10 weeks at ∼60% VO2max, which did not induce cardiac hypertrophy, but increased (P < 0.05) the soleus/body weight ratio, left ventricle capillarity and von Willebrand-positive cell density (n = 6). In another group of animals (n = 6) subjected to training followed by 4-week detraining, the soleus/body weight ratio returned to normal, with only partial
reversal of left ventricle capillarity and von Willebrand-positive cell density. Markers of angiogenesis (VEGF, KDR/VEGF-R2
and HIF-1α mRNA, studied by real-time RT-PCR) were upregulated at the end of training, and returned to baseline value after
detraining. Electron microscopy highlighted some morphological features in trained hearts (endothelial cell sprouting and
bridges and pericyte detachment), suggestive of endothelial cell proliferation and capillary growth that were absent in untrained
and detrained hearts. We conclude that the training-induced increase in cardiac capillarity and vascularization are retained
for some time upon cessation of the training program even in the absence of angiogenic stimuli. 相似文献
Molecular biophysics is a broad, diverse, and dynamic field that has presented a variety of unique challenges and opportunities for training future generations of investigators. Having been or currently being intimately associated with the Molecular Biophysics Training Program at Northwestern, we present our perspectives on various issues that we have encountered over the years. We propose no cookie-cutter solutions, as there is no consensus on what constitutes the "ideal" program. However, there is uniformity in opinion on some key issues that might be useful to those interested in establishing a biophysics training program. 相似文献
With the stress placed on our natural resources, many fisheries increasingly rely on restocking from hatchery-reared sources in an attempt to maintain commercially viable populations. However, the mortality rates of hatchery-reared fishes during the period directly following release are very high. The successful development of restocking programs is consequently dependent upon production and release strategies that lead to improved migratory, antipredator and feeding behaviour in hatchery fish. While relevant individual experience prior to release might improve performance, social learning potentially provides a process whereby fish can acquire locally adaptive behaviour rapidly and efficiently. It is now well over a decade since Suboski & Templeton (1989) raised the possibility of using social learning processes to improve the post-release survival of hatchery-reared fishes. This period has witnessed considerable progress in the understanding of how social learning operates in fish populations. We review new methods and recent findings that suggest how social learning protocols could realistically be applied on a large scale to enhance the viability of hatchery fish prior to their release into the wild. We also suggest a practical pre-release training protocol that may be applied at the hatchery level. 相似文献
Light and dark phase training may influences rodents’ physiologic parameters because these animals have nocturnal habits. Thus, we verify the effects of the training in different photoperiods on metabolism and corporal composition of rats. Eighteen rats were divided into three groups – G1: non-trained; G2: trained in the light phase; G3: trained in the dark phase. Rats were allowed to swim for 60 min, five times per week during six weeks. Trained animals presented a smaller weight gain and fat percentage in carcass. Rats of G3 increased gastrocnemius relative weight. The adipocyte diameter of G3 rats was smaller than the other groups. The levels of the total cholesterol, low-density proteins, and triacylglycerols were decreased in animals of G2 while the glycemia was increased. Training in light phase provided more alterations in the blood biochemical profile while the training in the dark increased the gastrocnemius weight and decreased the diameter of the adipocyte. 相似文献
1. 1. In this short review, previous studies regarding the modeling of lactate (La) response to exercise and its application to endurance training have been summarized.
2. 2. Additionally the result of a recent study by the present authors are shown.
3. 3. Several models for La response to step and ramp exercise are already proposed and deductions derived from them are used for practical purposes such as the prediction of race performance in middle-and long-distance runners as well as for construction of their training regimens.
4. 4. Only a limited number of models however have tried to quantify whole body La kinetics to exercise in humans concomitantly with describing physiological mechanisms underlying the observed phenomenon.
5. 5. In a recent study described further in this paper a 2 compartment model was used for the purpose of clarifying the current “La production vs degradation” controversy during La adaptation to training.
6. 6. It was determined from this investigation that the La metabolic clearance rate during recovery is enhanced by the endurance training.
7. 7. This is in accordance with another recent observation of an increased La metabolic clearance rate at high absolute work rates and all relative work rates during exercise.