Integrative Aspects of Cardiovascular Function

描述（申请人摘要）：本项目的总体目标是 进一步了解引起血液动力学的机制， 伴随着动态锻炼的调整。这些研究将调查 如何以及何时，机械（液压）因素，当地监管机制， 反射控制机制促进或阻碍这些调节。所有研究均 在有意识的、长期准备的动物中进行， 自愿跑步机锻炼。我们对人类的理解 在运动过程中，肌肉血液流动的调节源于我们无法 确定运动中血流量的增加有多少是由于 肌肉泵与代谢性血管舒张。目标1至3寻求填补这一空白 通过量化代谢血管舒张和肌肉之间的相互作用， 在机械因素（速度和坡度）变化期间抽水， 实现了给定量的跑步机工作。方法将是消除 血管舒张，从而揭示了孤立的肌肉泵的作用。 其他目标包括确定肌肉血流量与肌肉组织的紧密耦合程度。 运动过程中肌肉的机械活动（肌肉泵送）， 确定肌肉泵的血流量增加效果何时“消失” 在肌肉收缩之后。在目标4中，静脉系统在 将通过确定血液对心脏的影响来检查血液对心脏的作用， 主动改变心脏充盈压的分布 合规和不合规循环之间的输出。采取方法是 控制和操纵心输出量和后肢血流量（不符合 计算机控制的心室起搏和血管封堵器 cuffs.目标5旨在确定何时，如果有肌肉化学反射发挥作用， 在自主运动中的重要作用。最终目标6将决定 运动的影响，特别是肌肉化学反射， 动脉压力感受器反射刺激-反应曲线，以观察运动和/或肌肉 化学反射将压力反射“重置”到运动中的较高操作点。 从这些目标中获得的知识将进一步加深我们对 心血管系统如何运作的基本生理学以及 心力衰竭的血液动力学后果，外周血管异常， 和其他国家。

DESCRIPTION (Applicant's abstract): The overall goal of this project is to further our understanding of the mechanisms that evoke the hemodynamic adjustments that accompany dynamic exercise. These studies will investigate how, and when, mechanical (hydraulic) factors, local regulatory mechanisms, and reflex control mechanisms promote or impede these adjustments. All studies are to be carried out in conscious, chronically prepared animals at rest and during voluntary treadmill exercise. A fundamental gap in our understanding of the regulation of muscle blood flow during exercise stems from our inability to identify how much of the rise in blood flow in exercise is attributable to the muscle pump versus metabolic vasodilation. Aims 1 to 3 seek to fill this void by quantifying the interaction between metabolic vasodilation and muscle pumping during alterations in the mechanical factors (speed and grade) by which a given amount of treadmill work is achieved. The approach will be to eliminate vasodilation thereby revealing the effects of the muscle pump in isolation. Other goals include determining how tightly coupled muscle blood flow is to the mechanical activity of muscle (muscle pumping) during locomotion and to determine when the blood flow-raising effect of the muscle pump "wears-off' following a muscle contraction. In Aim 4, the role of the venous system in making blood available to the heart will be examined by determining the effect on cardiac filling pressure of actively changing the distribution of cardiac output between compliant and non-compliant circulations. The approach is to control and manipulate cardiac output and hindlimb blood flow (a non-compliant circulation) by computer controlled ventricular pacing and vascular occluder cuffs. Aim 5 seeks to determine when, if ever muscle chemoreflexes play an important role in voluntary locomotory exercise. The final Aim 6 will determine the influence of exercise, and specifically of muscle chemoreflexes, on arterial baroreflex stimulus-response curves to see if exercise and/or muscle chemoreflexes "reset" the baroreflex to a higher operating point in exercise. The knowledge gained from these aims will further our understanding of the basic physiology of how the cardiovascular system functions as well as the hemodynamic consequences of heart failure, peripheral vascular abnormalities, and other states.