Embryonic Hemodynamics: Ontogeny and Environmental Modifiers

9307832伯格伦心血管系统是脊椎动物胚胎发育中第一个运作的器官系统，其运输功能的正确建立对所有组织和器官随后的正常发育绝对至关重要。尽管心血管系统在早期起着重要的作用，但对于任何脊椎动物，包括鸟类和哺乳动物，对心血管系统的生理学发展仍然知之甚少。我们对无尾两栖动物(青蛙)的初步发现对促进我们对研究胚胎循环的一般特性的理解非常有用。因此，我们要求扩大我们对非洲爪蛙胚胎和幼体中央动脉血压和血流生成及其调控的研究，非洲爪蛙已成为发育生物学中主要的脊椎动物模型之一。这项建议的主要目标是：1)确定早期胚胎心脏的流量和压力产生的发展，以及2)确定导致组织氧合降低和血液运输需求变化的外部和内部影响如何影响胚胎和成人心血管系统的短期和长期表现。测量将包括记录心率、心输出量、血压、外周阻力和心脏做功。实验设计将包括在短期和长期暴露于低氧水平的条件下饲养发育中的胚胎群体，并随后评估它们的生理表现，以确定它们在发育过程中最容易受到环境干扰的时间。我们对生理发育以及环境条件对其影响的研究将对脊椎动物生理学和发育生物学具有非常广泛的适用性，特别是在几乎完全没有关于鸟类或哺乳动物胚胎EIT的类似公开数据的情况下。***

9307832 Burggren The cardiovascular system is the first organ system to operate in developing vertebrate embryos, and proper establishment of its transport functions is absolutely critical to the subsequent normal development of all tissues and organs. In spite of this important early role for the cardiovascular system, the development of its physiology remains very poorly understood for any vertebrate, including birds and mammals. Our initial findings on anuran amphibians (frogs) have been highly useful in advancing our understanding of studying the general properties of embryonic circulations. Consequently, support has been requested to expand our investigations of the development of central arterial blood pressure and flow generation and its regulation in embryos and larvae of the frog Xenopus laevis, which has become one of the major vertebrate models in development biology. The major objectives of this proposal are to: 1) determine the development of flow and pressure generation in the early embryonic heart, and 2) to determine how external and internal influences that lead to low tissue oxygenation and changes in blood transport demands affect both the short-term and long-term performance of the cardiovascular system in embryos and beyond to the adult. Measurement will include recordings of the heart rate heart output, blood pressure, peripheral resistance and heart work. The experimental design will encompass rearing populations of developing embryos under conditions that include short-term and long-term exposure to low oxygen levels, and subsequently assessing their physiological performance to determine when in development they are most vulnerable environmental disturbance. Our studies on physiological development and how environmental conditions impact upon it will have very broad applicability to both vertebrate physiology and developmental biology, particularly in the almost complete absence of similar published data on eit her bird or mammal embryos. ***