INTERACTION OF CARDIOVASCULAR REFLEXES IN EXERCISE

在高温下运动时，人体皮肤循环 参与体温和血压的调节， 皮肤血流量水平(SKBF)由 主动血管扩张(AVD)和血管紧张素转换酶的相互影响 血管收缩。我们建议研究一下 反射中的心肺和动脉压力感受器 在运动过程中控制前臂血流量(从而控制SKBF) 在我们的研究中强调这些反射如何相互作用 其他的和有体温调节反射的。我们将研究 不同压力感受器反射的刺激反应特性 操作颈动脉窦透壁或中心静脉 压力。前臂血管之间的线性关系 低下体负压(0)时测定的阻力(FVR)和中心静脉压(CVP) 至-20 mm Hg)将用于定义CP的灵敏度 压力反射。动脉压力感受性反射敏感性将定义为 每单位变化的血管阻力(总阻力或前臂阻力)变化 在颈动脉窦跨壁压力。我们将监控 在向监管中心输入输入信息之后 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 中心静脉压(CVP Line)和体温(核心和皮肤)。我们还将 监视以下传出响应作为 调节中心：心输出量(心阻抗图或二氧化碳 重复呼吸)、心率和前臂血流量(FBF)。SKBF将 根据FBF测量(静脉闭塞)进行估计 体积描记术)。我们将研究AVD可能是 受压力感受器反射活动的调节。假设，像其他人一样，AVD 活动与血管紧张素转换酶活性密切相关，AVD的调节 在压力感受器卸载过程中应该用改变的 控制局部出汗(露点湿度法)。

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).