Franken Paul, Gip Phung, Hagiwara Grace, Ruby Norman F, Heller H Craig
Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA.
Am J Physiol Regul Integr Comp Physiol. 2003 Aug;285(2):R413-9. doi: 10.1152/ajpregu.00668.2002. Epub 2003 May 1.
Sleep has been functionally implicated in brain energy homeostasis in that it could serve to replenish brain energy stores that become depleted while awake. Sleep deprivation (SD) should therefore lower brain glycogen content. We tested this hypothesis by sleep depriving mice of three inbred strains, i.e., AKR/J (AK), DBA/2J (D2), and C57BL/6J (B6), that differ greatly in their sleep regulation. After a 6-h SD, these mice and their controls were killed by microwave irradiation, and glycogen and glucose were quantified in the cerebral cortex, brain stem, and cerebellum. After SD, both measures significantly increased by approximately 40% in the cortex of B6 mice, while glycogen significantly decreased by 20-38% in brain stem and cerebellum of AK and D2 mice. In contrast, after SD, glucose content increased in all three structures in AK mice and did not change in D2 mice. The increase in glycogen after SD in B6 mice persisted under conditions of food deprivation that, by itself, lowered cortical glycogen. Furthermore, the strains that differ most in their compensatory response to sleep loss, i.e., AK and D2, did not differ in their glycogen response. Thus glycogen content per se is an unlikely end point of sleep's functional role in brain energy homeostasis.
睡眠在大脑能量稳态中具有功能上的关联，因为它可以用来补充清醒时耗尽的大脑能量储备。因此，睡眠剥夺（SD）应该会降低大脑糖原含量。我们通过剥夺三种近交系小鼠（即AKR/J（AK）、DBA/2J（D2）和C57BL/6J（B6））的睡眠来验证这一假设，这三种小鼠在睡眠调节方面差异很大。在进行6小时的睡眠剥夺后，这些小鼠及其对照组通过微波辐射处死，然后对大脑皮层、脑干和小脑中的糖原和葡萄糖进行定量分析。睡眠剥夺后，B6小鼠皮层中的这两项指标均显著增加约40%，而AK和D2小鼠脑干和小脑中的糖原含量则显著下降20%-38%。相比之下，睡眠剥夺后，AK小鼠所有三个结构中的葡萄糖含量均增加，而D2小鼠则没有变化。在食物剥夺条件下，B6小鼠睡眠剥夺后糖原的增加仍然存在，而食物剥夺本身会降低皮层糖原含量。此外，在对睡眠丧失的代偿反应中差异最大的品系，即AK和D2，在糖原反应方面并无差异。因此，糖原含量本身不太可能是睡眠在大脑能量稳态中功能作用的最终终点。
