Robin E D, Lewiston N, Newman A, Simon L M, Theodore J
Proc Natl Acad Sci U S A. 1979 Aug;76(8):3922-6. doi: 10.1073/pnas.76.8.3922.
The adaptations in the freshwater turtle that permit survival despite prolonged loss of mitochondrial ATP generation were investigated by comparing the bioenergetics of turtle brain slices with rat brain slices. Aerobic turtle brain shows no significant difference in basal levels of total ATP generation compared to rat brain; levels in turtle brain and rat brain were 18.4 +/- 2.8 (SD) and 19.4 +/- 2.2 mumol (100 mg of tissue)-1 hr-1, respectively. However, in turtle brain, a significantly greater fraction of ATP is derived from glycolysis both under aerobic and anaerobic conditions [aerobic turtle (24%) and rat (13%), P less than 0.02; anaerobic, turtle (28%) and rat (18%), P less than 0.05]. The increased glycolytic capacity is related to high levels of rate-limiting glycolytic enzymes, such as pyruvate kinase (EC 2.7.1.40). Turtle brain operates close to glycolytic capacity even under aerobic conditions, and no Pasteur effect can be demonstrated. Quantitatively, anaerobic glycolysis accounts for a maximum of 28% of basal aerobic ATP generation, suggesting that prolonged diving is also accompanied by a reduction in brain energy requirements. The adaptation subserving short-term (natural) diving is an increase in brain glycolytic capacity. The adaptation subserving prolonged diving (days to weeks) may be a reduction in the energy requirements of brain (and other cells).
通过比较淡水龟脑切片和大鼠脑切片的生物能量学，研究了淡水龟在长时间线粒体ATP生成丧失的情况下仍能存活的适应性机制。有氧条件下，龟脑的总ATP生成基础水平与大鼠脑相比无显著差异；龟脑和大鼠脑的水平分别为18.4±2.8（标准差）和19.4±2.2 μmol（100 mg组织）-1 h-1。然而，在龟脑中，无论是有氧还是无氧条件下，来自糖酵解的ATP比例都显著更高[有氧条件下，龟（24%）和大鼠（13%），P<0.02；无氧条件下，龟（28%）和大鼠（18%），P<0.05]。糖酵解能力的增强与限速糖酵解酶（如丙酮酸激酶，EC 2.7.1.40）的高水平有关。即使在有氧条件下，龟脑也接近糖酵解能力运行，且未表现出巴斯德效应。从数量上看，无氧糖酵解最多占基础有氧ATP生成的28%，这表明长时间潜水还伴随着脑能量需求的降低。适应短期（自然）潜水的机制是脑糖酵解能力的增强。适应长时间潜水（数天至数周）的机制可能是脑（和其他细胞）能量需求的降低。
