Regulation of muscle glycogen metabolism in fish

鱼类肌糖原代谢的调节

• 批准号: 156196-2006
• 负责人: Milligan, Louise
• 金额: $ 1.43万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=340384
• 关键词: Regulation; muscle; glycogen; metabolism; fish

Fish routinely undergo periods of exhaustive exercise when angled or negotiating currents during upstream migrations or when caught by commercial fishing vessels.  This exercise, characterized by high-intensity bursts of swimming is powered by the white muscle fibers.  The first 20 sec of exercise is fueled by the breakdown of high energy phosphates, creatine phosphate (PCr), and later, adenosine trisphosphate (ATP). Because the demand for ATP outstrips the supply available via oxidative metabolism, anaerobic glycolysis is invoked, with glycogen as the prime carbon source.  At exhaustion, muscle ATP, PCr and glycogen levels are depleted while lactate accumulates.  Although we understand the changes that occur within the muscle associated with this type of swimming activity, we know very little about how the muscle, hence the fish, recovers. Even the very basic question of what substrates the muscle is using for glycogenesis is unknown, particularly how a growing fish lays down glycogen in new muscle fibers. Little is also known about how other factors, such as dietary habits (carnivore vs. omnivore vs. herbivore) may influence recovery via influences on substrate use.  We also don't know how much recovery of muscle is required to allow fish to burst perform again.  Being able to provide answers to these questions, in addition to expanding our understanding of fish muscle physiology, may have application to the real word. Understanding regulation of muscle recovery has resulted in modified procedures in catch and release fishery, and may impact the handling of non-target species in the commercial fishery to reduce mortality. I will focus on growing trout to ask the basic question of how new muscle lays down glycogen and an inter-specific approach to ask about how dietary habits and/or phylogeny influences muscle metabolism by comparing closely related carnivores (trout and lake whitefish) to related herbivores and omnivores (grass carp, goldfish, common carp) to related herbivore and carnivore (gizzard shad, alewife).

在上游迁徙或被商业渔船捕获时，鱼类通常会经历一段时间的精疲力竭的运动。这种运动的特点是高强度的突发性游泳是由白色肌肉纤维提供动力的。在前20秒的运动中，高能磷酸盐、磷酸肌酸(PCR)和后来的三磷酸腺苷(ATP)的分解为运动提供了能量。由于对ATP的需求超过了氧化代谢可获得的供应，因此需要进行厌氧糖酵解，糖原是主要的碳源。在精疲力竭的情况下，肌肉的ATP、聚合酶链式反应和糖原水平会耗尽，而乳酸会积累。尽管我们了解与这种类型的游泳活动相关的肌肉内发生的变化，但我们对肌肉，即鱼的恢复知之甚少。甚至连肌肉用什么底物来进行糖生成这个最基本的问题都是未知的，特别是成长中的鱼是如何在新的肌肉纤维中沉积糖原的。我们也很少知道其他因素，如饮食习惯(食肉动物、杂食动物和草食动物)如何通过影响底物的使用来影响恢复。我们也不知道需要多少肌肉恢复才能让鱼再次表现出来。除了扩大我们对鱼类肌肉生理学的理解之外，我们能够为这些问题提供答案，可能也适用于真正的世界。了解肌肉恢复的规则已导致修改捕捞和放流渔业的程序，并可能影响商业渔业中非目标物种的处理，以降低死亡率。我将集中在生长鲑鱼上，提出新肌肉如何分解糖原的基本问题，以及通过比较密切相关的食肉动物(鲑鱼和湖泊白鱼)与相关的食草动物和杂食性动物(草鱼、金鱼、鲤鱼)与食草动物和食肉动物(沙鱼、银鱼)的亲缘关系，来问饮食习惯和/或系统发育如何影响肌肉新陈代谢。