INTERACTION OF CARDIOVASCULAR REFLEXES IN EXERCISE

在高温下运动时，人体皮肤循环 参与体温和血压调节， 皮肤血流量水平（SKBF）由 主动血管舒张（AVD）和 血管收缩 我们建议研究 反射中的心肺（CP）和动脉压力感受器 运动过程中前臂血流量（以及SKBF）的控制， 在我们的研究中强调这些反射是如何与每个 其他的和体温调节反射。 我们会研究 通过选择性地测量每个压力感受器反射的刺激-反应特性， 操作颈动脉窦透壁或中央静脉 压力 前臂血管的线性关系 在低水平LBNP（0 至-20 mm Hg）将用于定义CP的灵敏度 压力反射 动脉压力反射敏感性定义为 每单位变化的血管阻力变化（总阻力或前臂阻力） 颈动脉窦跨壁压 我们会监察 随着传入输入到调节中心， 选择性和联合压力感受器刺激：动脉血 压力（无创，Dinamap），中心静脉压（19 gauge CVP线）和体温（核心和皮肤）。 我们还将 监测以下传出反应，作为 调节中心：心输出量（阻抗心动图或CO2 重复呼吸）、心率和前臂血流量（FBF）。 SKBF将 根据FBF测量值（静脉闭塞）进行估计 体积描记法）。 我们将研究AVD可能是 由压力反射活动调节。 与其他人一样，假设AVD 活动与催汗活动密切相关，AVD的调节 在压力感受器卸载期间，应该由改变的 控制局部出汗（露点湿度）。

During exercise in the heat the human cutaneous circulation participates in both temperature and blood pressure regulation, with the level of skin blood flow (SKBF) determined by the competing influences of active vasodilation (AVD) and vasoconstriction. We propose to examine the role of cardiopulmonary (CP) and arterial baroreceptors in the reflex control of forearm blood flow (and thus SKBF) during exercise by emphasizing in our studies how these reflexes interact with each other and with thermoregulatory reflexes. We will examine the stimulus-response characteristics of each baroreflex by selectively manipulating either carotid sinus transmural or central venous pressure. The linear relationship between forearm vascular resistance (FVR) and CVP determined during low levels of LBNP (0 to -20 mm Hg) will be used to define the sensitivity f the CP baroreflex. Arterial baroreflex sensitivity will be defined as the change in vascular resistance (total or forearm) per unit change in carotid sinus transmural pressure. We will monitor the following afferent inputs into the regulatory centers during selective and combined baroreceptor stimulation: arterial blood pressure (non-invasive, Dinamap), central venous pressure (19 gauge CVP line), and body temperature (core and skin). We will also monitor the following efferent responses as outputs from the regulatory centers: cardiac output (impedance cardiography or CO2 rebreathing), heart rate, and forearm blood flow (FBF). SKBF will be estimated from FBF measurements (venous occlusion plethysmography). We will examine the possibility that AVD may be modulated by baroreflex activity. Assuming, as others, that AVD activity is closely linked to sudomoter activity, modulation of AVD during baroreceptor unloading should be indicated by an altered control of local sweating (dew-point hygrometry).