UNIT CONTROL OF MUSCLE BLOOD FLOW

肌肉血流的单位控制

• 批准号: 6030765
• 负责人: STEVEN S SEGAL
• 金额: $ 26.63万
• 依托单位: JOHN B. PIERCE LABORATORY, INC.
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2001-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6030765
• 关键词: acetylcholine; arterioles; capillary; curare; electrostimulus; fluorescence microscopy; hamsters; innervation; microcirculation; microelectrodes; motor neurons; muscle; muscle contraction; neuromuscular junction; neuropharmacology; perfusion; vascular smooth muscle nervous control; vasodilation; video microscopy

DESCRIPTION (Applicant's abstract): The goal of this research is to elucidate the anatomical and physiological interactions among muscle fibers, motor nerves, and the local control of capillary perfusion. The thin, parallel-fibered hamster retractor muscle has been developed as a model system for studying these interactions using video microscopy and image analysis. When muscle fibers are active, oxygen requirements increase along their entire length, which encompasses many microvascular units (MVUs) of capillary flow control. However, the anatomical correspondence among MVUs which supply a fiber or fiber bundle is not understood. Therefore, AIM I is to define the organization and perfusion of MVUs with respect to muscle fiber position and contractile activity. Through imaging microvessels and muscle fibers, we will test the hypotheses that (i) MVUs align with muscle fibers; and that (ii) MVUs supplying a fiber (bundle) originate from common parent arterioles. Stimulation with microelectrodes will be used to test the hypothesis that (iii) muscle fiber contraction results in perfusion of MVUs along the active fibers. Acetylcholine (ACh) triggers vasodilation that is conducted rapidly along the arteriolar wall to increase MVU perfusion. Because neuromuscular junctions (NMJs) are the source of ACh in muscle, AIM II is to define the spatial and functional relationships among NMJs and MVUs. By labeling and imaging NMJs and MVUs, we will test the hypothesis that (i) motor innervation corresponds with microvascular topology. Stimulating NMJs while observing blood flow in microvessels will be used to test the hypotheses that perfusion of MVUs is coordinated with muscle fiber activation via ACh release at NMJs. The influence of motor unit recruitment on MVU perfusion is unknown. By defining the functional properties of motor units in the retractor muscle and observing MVU perfusion in response to motor unit stimulation, we will test the hypotheses that (i) each motor unit has fibers distributed throughout the muscle, that (ii) fibers within a given MVU derive from different motor units, and that (iii) motor unit recruitment is accompanied by MVU recruitment. Our long term goal is to elucidate physiological and pathophysiological interaction(s) among muscle fibers, motor nerves, and the local control of blood flow at the cellular level in vivo. We envision a new foundation from which to test hypotheses concerning the determinants of physical performance in healthy individuals as well as the mechanisms responsible for changes in work capacity with training, disuse or disease, and during the normal course of aging.

描述（申请人的摘要）：这项研究的目的是 阐明肌肉纤维之间的解剖学和生理相互作用， 运动神经和毛细血管灌注的局部控制。 瘦， 平行型仓鼠牵开器肌肉已开发为模型 使用视频显微镜和图像研究这些相互作用的系统 分析。 当肌肉纤维活跃时，氧气需求随着 它们的整个长度，包括许多微血管单元（MVU） 毛细管流控制。 但是，MVU之间的解剖对应关系 供应纤维或纤维束的哪个尚不清楚。 因此，目标我是 定义MVU有关肌肉的组织和灌注 纤维位置和收缩活动。 通过成像微磨和 肌肉纤维，我们将测试（i）MVUS与肌肉保持一致的假设 纤维； （ii）提供纤维（束）的mvus起源于普通 家长动脉。 用微电极刺激将用于测试 （iii）肌肉纤维收缩的假设导致 沿活动纤维的MVU。 乙酰胆碱（ACH）触发血管舒张 沿着小动脉壁迅速进行以增加MVU 灌注。 因为神经肌肉连接（NMJ）是ACH的来源 肌肉，目标II是定义之间的空间和功能关系 NMJS和MVU。 通过标记和成像NMJ和MVU，我们将测试 假设（i）运动神经与微血管相对应 拓扑。 刺激NMJ，同时观察微血管中的血流 用于测试MVUS灌注与 通过NMJS释放的ACH激活肌肉纤维。 电机的影响 MVU灌注的单位募集尚不清楚。 通过定义功能 电动机单位在牵引力肌肉中的特性和观察MVU的特性 为了响应运动单位刺激的灌注，我们将测试假设 （i）每个电动机单元都有在整个肌肉中分布的纤维， （ii）给定MVU内的纤维来自不同的电动机单元，并且 （iii）运动单元招募伴随MVU招募。 我们的漫长 术语目标是阐明生理和病理生理学 肌肉纤维，运动神经和局部控制之间的相互作用 体内细胞水平的血流。 我们设想了一个新的基础 要测试有关身体绩效决定因素的假设 在健康个体以及负责变化的机制中 培训，废除或疾病以及正常过程中的工作能力 衰老。