Suarez R K, Doll C J, Buie A E, West T G, Funk G D, Hochachka P W
Department of Zoology, University of British Columbia, Vancouver, Canada.
Am J Physiol. 1989 Nov;257(5 Pt 2):R1083-8. doi: 10.1152/ajpregu.1989.257.5.R1083.
When temperature differences are taken into account, turtle brains use glucose at one-sixth the rate reported in rat brains. Na+-K+-ATPase activities are 2- to 2.5-fold higher in rat than in turtle brains. Maximal activities of hexokinase and lactate dehydrogenase are similar, whereas citrate synthase activities are two- to threefold higher in rat than turtle brains at the respective biological temperatures. Voltage-dependent Ca2+ channel densities, when compared between the two species, showed no consistent pattern. These data, along with the threefold differences in density of voltage-dependent Na+ channels reported by Lutz et al., are consistent with the idea that lower rates of channel and pump-mediated Na+ and K+ fluxes result in lower rates of aerobic energy metabolism in turtle brains compared with rat brains.
当考虑到温度差异时，海龟大脑利用葡萄糖的速率仅为大鼠大脑所报道速率的六分之一。大鼠大脑中Na+-K+-ATP酶的活性比海龟大脑高2至2.5倍。己糖激酶和乳酸脱氢酶的最大活性相似，而在各自的生理温度下，大鼠大脑中柠檬酸合酶的活性比海龟大脑高两至三倍。在这两个物种之间比较时，电压依赖性Ca2+通道密度没有呈现出一致的模式。这些数据，连同Lutz等人报道的电压依赖性Na+通道密度的三倍差异，都与以下观点一致：与大鼠大脑相比，通道和泵介导的Na+和K+通量较低，导致海龟大脑中需氧能量代谢率较低。
