CENTRAL INTERACTION OF BARORECEPTOR & SOMATIC AFFERENTS

压力感受器的中枢相互作用

• 批准号: 6403252
• 负责人: Jeffrey Thomas Potts
• 金额: $ 14.83万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-10-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6403252
• 关键词: baroreceptors; baroreflex; carotid sinus; cats; dogs; electrophysiology; horseradish peroxidase; immunocytochemistry; neural plasticity; neuroanatomy; neurophysiology; somatic afferent nerve; striated muscles; synapses

Sympathetic cardiovascular mechanisms are modified by chronic diseases, such as congestive heart failure, as well as by acute stress such as physical activity or exercise. The overall aim of this proposal is to understand the central mechanisms that contribute to the "plasticity" of the arterial baroreceptor reflex arc. Hypothesis number 1: Contraction-induced activation of skeletal muscle receptors modulate the carotid baroreflex. Effect of mechanically and metabolically-sensitive hindlimb skeletal muscle afferent activity on carotid baroreceptor reflex function will be investigated. Carotid baroreceptors will be characterized using the isolated and perfused carotid sinus preparation in anesthetized dogs, and skeletal muscle receptors will be activated by ventral root stimulation and passive muscle stretch. Experiments will define the operational properties of the carotid baroreflex, as well as identify frequency-dependent characteristics of the reflex using transfer function analysis. Hypothesis number 2: Nucleus tractus solitarii (NTS) is the neural substrate for afferent baroreceptor and skeletal muscle receptor fibers. Skeletal muscle afferent fibers will be traced to the NTS using lectin-conjugated horseradish peroxidase (HRP) applied to the tibial nerve in cats. Colocalization of HRP- positive NTS neurons with Fos-positive neurons activated by muscle contraction will be determined utilizing immunohistochemical staining techniques. Hypothesis number 3: Afferent input from skeletal muscle receptors alters the excitability of barosensitive NTS neurons. Extracellular single- unit activity will be recorded from NTS neurons during controlled activation of the baroreflex and the skeletal muscle reflex using both canine and feline models. The primary focus of these studies is to determine the role for differential spike firing patterns in NTS neurons. The proposed experiments will be conducted at both the systems and the cellular levels. Results from these experiments will provide new information regarding the synaptic processing of visceral inputs by NTS neurons. This knowledge may help us to better understand the central mechanisms that alter arterial baroreflex control of cardiovascular function in both health and disease.

交感心血管机制被慢性改变 疾病，例如充血性心力衰竭以及急性 压力，例如体力活动或锻炼。 总体目标是 该建议旨在了解中央机制 有助于动脉压力感受器的“可塑性” 反射弧。 假设 1：收缩诱导的激活 骨骼肌受体调节颈动脉压力反射。 机械和代谢敏感后肢的影响 骨骼肌传入活动对颈动脉压力感受器反射的影响 函数将被研究。 颈动脉压力感受器将 使用分离和灌注的颈动脉窦进行表征 麻醉犬和骨骼肌受体的制剂 将被腹根刺激和被动肌肉激活 拉紧。 实验将定义操作属性 颈动脉压力反射，以及识别频率依赖性 使用传递函数分析反射的特征。 假设 2：孤束核 (NTS) 是 传入压力感受器和骨骼肌的神经基质 受体纤维。 将追踪骨骼肌传入纤维 使用凝集素缀合辣根过氧化物酶 (HRP) 转入 NTS 适用于猫的胫神经。 HRP-的共定位 阳性 NTS 神经元与 Fos 阳性神经元激活 肌肉收缩将利用确定 免疫组织化学染色技术。 假设 3： 来自骨骼肌受体的传入输入改变 压力敏感 NTS 神经元的兴奋性。 细胞外单 单位活动将在受控期间从 NTS 神经元记录 使用压力反射和骨骼肌反射的激活 犬科动物和猫科动物模型。 这些的主要焦点 研究的目的是确定差异尖峰发射的作用 NTS 神经元中的模式。 拟议的实验将是 在系统和细胞水平上进行。 结果 这些实验将提供有关 NTS 神经元对内脏输入的突触处理。 这 知识可以帮助我们更好地理解中心机制 改变动脉压力反射对心血管功能的控制 在健康和疾病方面。