REFLEX CONTROL OF CIRCULATION DURING EXERCISE

拟议中的实验将定义来自活动肌肉的传入 (肌肉反射)、心肺受体和动脉 压力感受器相互作用产生心血管反应(包括心脏 和血管运动)，在清醒的狗中进行动态运动。初级阶段 假说是流向工作肌肉的血液减少会激活 肌肉传入(第三组和第四组化学感受器)，依次启动 心血管系统中恢复肌肉血液的反射调节 回流到咬合前的水平。描述了以下技术： 为活跃的肌肉产生分级的血流量减少，同时 评估心血管效应反应，包括血压、心脏 不同脏器循环的心率、心输出量和血流量 (肾脏、肠系膜)。这项提案中概述的实验将 检查来自活动肌肉的反射的性质，无论是在 正常的狗和当心脏功能严重时进行运动的动物 有限的。活动性肌肉的血流灌注量与肌力的关系 伴随的全身心血管反应(S)是在 正常动物和消除动脉压力感受器输入后 和/或心脏受体。该提案利用技术来选择性地 心脏传入神经与动脉压力感受器的联合作用 去神经程序。他们一起提供了一只稳定的慢性狗 允许对回答进行多次比较的准备工作 延长的时间段。在此开发的实验方法 建议，将提供有价值的新数据来确定传入 正常运动中循环调控机制的研究进展 在动物和那些心脏功能严重受限的人中。 重要的是，它评估了肌肉传入在控制 剧烈运动时的心功能和内脏血流，数据 目前还不适用于有意识的狗模型。

The proposed experiments will define how afferents from active muscle (muscle reflex), the cardiopulmonary receptors and the arterial baroreceptors interact to produce the cardiovascular response (both cardiac and vasomotor), to dynamic exercise in the conscious dog. The primary hypothesis is that reductions in blood flow to working muscle activates muscle afferents (Group III and IV chemoreceptors) which in turn initiate reflex adjustments in the cardiovascular system to restore muscle blood flow back towards pre-occlusion levels. Techniques are described for producing graded blood flow reductions to active muscle, while concurrently assessing cardiovascular effector responses including blood pressure, heart rate, cardiac output and blood flow in various visceral circulations (renal, mesenteric). The experiments outlined in this proposal will examine the nature of the reflex arising from active muscle, both in the normal dog and in animals exercised when cardiac performance is severely limited. The relationship between perfusion of active muscle and the accompanying systemic cardiovascular response(s) is determined in the normal animal and after eliminating input from arterial baroreceptors and/or cardiac receptors. This proposal utilizes techniques for selective cardiac afferent denervation in conjunction with arterial baroreceptor denervation procedures. Together they provide a stable chronic dog preparation which allows multiple comparisons of responses to be made over extended periods of time. The experimental approaches, developed in this proposal, will provide valuable new data to determine the afferent mechanisms involved in control of the circulation during exercise in normal animals and in those with severe limitations of cardiac performance. Importantly, it evaluates the influence of muscle afferents in control of both cardiac function and visceral blood flow during severe exercise, data not presently available for the conscious dog model.