Understanding What Limits Fish Cardiovascular Performance and Environmental Responses

了解鱼类心血管性能和环境反应的限制因素

• 批准号: RGPIN-2016-04481
• 负责人: Gamperl, Anthony
• 金额: $ 4.44万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=691094
• 关键词: Understanding; What; Limits; Fish; Cardiovascular; Understanding; What; Limits; Fish; Cardiovascular

The cardiorespiratory system (gills, heart, blood, blood vessels) is critical to survival because it ensures adequate oxygen and nutrient delivery to the tissues, and removes metabolic wastes. My research program uses an integrative (molecular to whole animal) approach to look at how oxygen consumption (e.g. metabolism and metabolic capacity), heart function, blood vessel function/physiology and stress (catecholamine and cortisol levels, receptor types / levels) differ between fish species and how this allows them to survive under challenging conditions. While I have made tremendous progress in understanding the plasticity of fish cardiac function and its relationship to performance / survival, this research has left many important questions unanswered and generated several new hypotheses. I address a number of these in this grant application. *** Three fundamental questions in fish cardiovascular physiology are: 1) what factors / mechanisms determine between individual and between species differences in maximum heart rate?; 2) what limits heart rate at high temperatures?; and 3) what mechanisms constrain the capacity of fishes to increase stroke volume (how much blood is pumped per beat) as temperatures rise. I will examine all of these questions.**** Recent studies in my lab have shown that fish exposed to low oxygen (hypoxia) for prolonged periods have compromised heart function, but that these species can consume more oxygen per volume of blood pumped. Thus, I will investigate whether this latter effect is due to changes in mitochondrial function and/or alterations in factors related to oxygen uptake and diffusion. Further, I will examine whether the heart's reduced pumping capacity is due to a limited capacity of the heart muscle to contract, and why.**** I will conduct a number of studies on very small coronary vessels (i.e, microvessels, the ones that are most important in controlling blood flow to tissues), and similar vessels in the ovary and intestine of trout. The former studies are a continuation of previous work, and are critical as coronary blood flow is key to cardiac performance under stressful conditions. The studies on trout intestinal and ovarian vessels will be performed because perfusion of these two vascular beds is important for digestion and egg development, respectively, and data on coronary vessels may not reflect how temperature or various hormones affect vasomotor responses, and thus blood flow, in other tissues.*Finally, I will investigate the impact of an immune-related protein (interleukin-1) on cardiac performance and vascular resistance in trout, and determine the mechanisms involved. This molecule is an important mediator of post-infection disease-related processes.**** This research will greatly enhance the depth and breadth of our understanding of how the fish cardiorespiratory system responds to stressors, and thus, if/when their survival is threatened. **

心肺系统（Gills，心脏，血液，血管）对于生存至关重要，因为它可以确保足够的氧气和营养物向组织的递送，并消除了代谢废物。我的研究计划采用综合性（分子至整个动物）方法来研究氧消耗（例如代谢和代谢能力），心脏功能，血管功能 /生理学和压力（Catecholamine and Cortisol水平，受体类型 /水平）在鱼类物种之间的差异以及如何在挑战性的条件下生存。尽管我在理解鱼类心脏功能的可塑性及其与性能 /生存的关系方面取得了巨大进展，但这项研究留下了许多重要的问题，并产生了一些新的假设。我在此赠款申请中解决了其中的许多。 ***鱼类心血管生理学中的三个基本问题是：1）在最大心率中，个体和物种差异之间的哪些因素 /机制决定？ 2）什么会限制高温下的心率？ 3）什么机制限制了随着温度升高，鱼类增加了中风量（每次粉刷多少血液）的能力。我将研究所有这些问题。****在我的实验室中的最新研究表明，长时间暴露于低氧（缺氧）的鱼会损害心脏功能，但这些物种每次泵送的血液可以消耗更多的氧气。因此，我将研究后一种效应是否是由于线粒体功能的变化和/或与氧气摄取和扩散有关的因素的变化所致。此外，我将检查心脏降低的泵送能力是否是由于心肌的收缩能力有限，以及为什么。以前的研究是先前工作的延续，并且至关重要，因为冠状动脉血流是压力条件下心脏表现的关键。将进行有关鳟鱼肠道和卵巢血管的研究，因为这两个血管床的灌注对于分别对于消化和卵发育至关重要，冠状血管的数据可能无法反映温度或各种激素影响血管舒张剂的反应，以及因此在其他组织中的血液流动。确定所涉及的机制。该分子是感染后与疾病相关过程的重要介体。 **