INTERACTION OF CARDIOVASCULAR REFLEXES IN THERMAL STRAIN

描述（改编自申请人的摘要）：长期目标 本研究旨在了解皮肤血流的调节， 强调各种生理系统之间的相互作用， 控制过程。在过去，这些研究人员一直专注于调制 通过压力感受器和温度感受器对皮肤血流进行温度调节控制 介导反射在目前的建议中，他们继续这些类型的 调查和补充这项工作的确切性质的探索 皮肤交感神经活动和皮肤活动之间的联系 血管舒张在皮肤交感神经活动（SSNA）的变化期间， 通过显微神经摄影术直接测量，它们将表征效应器 使用激光多普勒测速仪（LDV）评估人体皮肤的器官反应， 皮肤血液和露点湿度的变化来评估出汗。到 了解SSNA和效应器官反应之间的联系， 使用皮内微透析进行特定的药物阻断 剂.微透析和LDV的结合提供了一种创新的， 明确的方法来控制皮肤血流的研究。他们将 描述SSNA自发爆发之间的关系 和同时发生的体温调节反应（即，主动血管舒张或 出汗）。他们希望证明SSNA的爆发是由 血管舒张和血管收缩信号。该模型将结合使用 用特异性受体拮抗剂来描述 乙酰胆碱，一氧化氮和血管活性肽在这种体温调节 反应这种实验方法提供了足够的保真度来解剖 这些不同的地方因素的相对贡献， 皮肤血液流动的温度调节控制。最后，调查人员将 检查肌肉代谢反射的激活与 皮肤血液流动的温度调节控制。这些研究将提高我们的 了解神经源性皮肤血管舒张的过程及其 在组合和竞争需求期间的控制，这些需求导致 几个生理控制系统与体温调节反应。这些 研究应该提供与人类使用的机制相关的新知识， 在高循环和热应激条件下抵抗晕厥。

DESCRIPTION (Adapted from the applicant's abstract): The long-term objective of this research is to understand the regulation of skin blood flow with specific emphasis on the interaction between various physiological systems in this control process. In the past these investigators have focused on the modulation of thermoregulatory control of skin blood flow by baroreceptor and osmoreceptor mediated reflexes. In the present proposal they continue these types of investigations and complement this work with an exploration of the exact nature of the link between cutaneous sympathetic nerve activity and active cutaneous vasodilation. During changes in skin sympathetic nerve activity (SSNA), measured directly by microneurography, they will characterize the effector organ responses of human skin using laser Doppler velocimetry (LDV) to assess changes in skin blood and dew-point hygrometry to assess sweating. To understand the link between SSNA and effector organ responses the investigators use intradermal microdialysis to administer specific pharmacological blocking agents. The combination of microdialysis and LDV provides an innovative and unambiguous approach to the study of control of skin blood flow. They will characterize the relationship between spontaneously occurring bursts of SSNA and coincident thermoregulatory responses (i.e. , active vasodilatation or sweating). They expect to demonstrate that bursts of SSNA are composed of vasodilator and vasoconstrictor signals. This model will be used in combination with specific receptor antagonists to describe the contribution of acetylcholine, nitric oxide, and vasoactive peptides in this thermoregulatory response. This experimental approach provides sufficient fidelity to dissect out the relative contribution of these various local factors in thermoregulatory control of skin blood flow. Finally, the investigators will examine the interaction between activation of muscle metaboreflexes and thermoregulatory control of skin blood flow. These studies should improve our understanding of the process of neurogenic cutaneous vasodilatation and its control during combined and competing demands that result in the interaction of several physiological control systems with thermoregulatory responses. These studies should provide new knowledge related to mechanisms that humans employ to resist syncope in conditions of high circulatory and thermal stress.