INTERACTION OF CARDIOVASCULAR REFLEXES IN THERMAL STRAIN

描述(改编自申请人的摘要)： 本研究旨在了解特定条件下皮肤血流的调节规律。 强调在这一过程中各种生理系统之间的相互作用 控制过程。在过去，这些研究人员将重点放在调制 压力感受器和渗透压感受器对皮肤血流的体温调节作用 中介性反射。在本提案中，他们继续这些类型的 调查和补充这项工作，并探索确切的性质 皮肤交感神经活动和皮肤活动之间的联系 血管扩张。在皮肤交感神经活动(SSNA)变化期间， 通过显微神经学直接测量，它们将描述效应器的特征 激光多普勒测速仪评价人体皮肤器官反应 皮肤血液和露点湿度的变化，以评估出汗。至 了解SSNA和效应器官反应之间的联系 皮内微渗析用于特异性药物阻断 探员们。微透析和LDV的结合提供了一种创新的和 毫不含糊地研究皮肤血流的控制。他们会 描述SSNA自发爆发之间的关系 和一致的体温调节反应(即主动血管扩张或 大汗淋漓)。他们希望证明SSNA的爆发由以下几个部分组成 血管扩张剂和血管收缩信号。这一型号将结合使用 用特定的受体拮抗剂来描述 体温调节中的乙酰胆碱、一氧化氮和血管活性多肽 回应。这种实验方法提供了足够的保真度来解剖 计算出这些不同的本地因素在 皮肤血液流动的体温调节控制。最后，调查人员将 研究肌肉代谢性反射的激活和 皮肤血液流动的体温调节控制。这些研究应该会改善我们的 对神经源性皮肤血管扩张过程的认识及其临床意义 在导致交互的组合和竞争需求期间的控制 几个具有体温调节反应的生理控制系统。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.