ARTERIAL BAROREFLEX CONTROL OF BLOOD PRESSURE-- EXERCISE

描述(申请人摘要)：以前，我们已经证明 动态运动中颈动脉压力感受性反射对血压的控制 经典地重置为动态运动的主流血压。 主动脉压力感受性反射对心率的控制也被重置为主流血液。 压力在最大增益不变的情况下。此外，我们的发现表明 在静止状态下，动脉压力感受器反射功能受到有氧健身的调节， 心肺压力感受器负荷和肌内压力增加。 然而，1)动脉压力感受器反射在 运动，2)肌肉压力增加和 动脉压力感受器反射功能；3)有氧健身对动脉的影响 心肺压力感受器反射功能仍维持在规定的水平。我们假设 中央指令的前馈机制重置压力反射 与运动活动的诱导和对此的持续调节平行 重置是通过激活肌内机械感受器来实现的 活跃的组织。我们进一步假设，有氧健身的增加 结果导致血容量增加和主动脉重置 心肺压力反射。为了测试这些假设，我们将使用 历史上独一无二的实验范式，其中肌肉肌腱振动将 用于有选择地增加或减少中央命令。在稳定期间 有无状态运动(恒定运动加压反射输入) 肌腱振动时，颈动脉压力感受器反射功能 使用我们实验室开发的程序进行测定。使用类似的 实验范式与利用下半身增加肌内压力 正压、中枢指令与肌内指令的相互作用 将对压力进行检查。此外，使用在我们的 MSNA、NE溢出和腿部血管传导性的实验室和测量 将选择性地模拟高位和高位的主动脉和心肺压力感受器反射 低适合度耐力训练受试者。这是一个独特的方面 调查表明，获得的数据与健康状况直接相关 并将提供重要的基本信息 患者体力活动时血压调节情况的调查研究 有心力衰竭、高血压和间歇性跛行。

DESCRIPTION (Applicant's abstract): Previously, we have demonstrated that the carotid baroreflex control of blood pressure during dynamic exercise is classically reset to the prevailing blood pressure of the dynamic exercise. Aortic baroreflex control of heart rate was also reset to the prevailing blood pressure without a change in maximal gain. Additionally, our findings suggest that at rest the arterial baroreflex function is modulated by aerobic fitness, cardiopulmonary baroreceptor load and increases in the intramuscular pressure. However, the mechanisms by which 1) the arterial baroreflexes are reset during exercise, 2) the interaction between increases in muscle pressure and the arterial baroreflex function, and 3) the effect of aerobic fitness on arterial and cardiopulmonary baroreflex function remain to the defined. We hypothesize that the feed forward mechanism of central command resets the baroreflexes in parallel with the induction of motor activity and continuous modulation of this resetting is provided by activation of intramuscular mechanoreceptors within the active tissue. We further hypothesize that increases in aerobic fitness results in an increased blood volume and a resetting of the aortic and cardiopulmonary baroreflex. In order to test these hypotheses we will use a historically unique experimental paradigm in which muscle tendon vibration will be used to selectively increase or decrease central command. During steady state exercise (a constant exercise pressor reflex input) with and without muscle tendon vibration, carotid arterial baroreflex function will be determined using procedures developed in our laboratory. Using a similar experimental paradigm and increasing intramuscular pressure by using lower body positive pressure, the interactions between central command and intramuscular pressure will be examined. Additionally, using techniques developed in our laboratory and measures of MSNA, NE spill-over and leg vascular conductance we will selectively model the aortic and cardiopulmonary baroreflexes of high and low fit endurance exercise trained subjects. A unique aspect of this investigation is that the data obtained is immediately relevant to the healthy human and will provide significant fundamental information for the investigation of blood pressure regulation during physical activity of patients with heart failure, hypertension and intermittent claudication.