CENTRAL INTERACTION OF BARORECEPTOR & SOMATIC AFFERENTS

交感心血管机制被慢性 疾病，如充血性心力衰竭，以及急性 压力，如体力活动或锻炼。 的总体目标 这一建议是为了了解中央机制， 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 骨骼肌感受器调节颈动脉压力感受器反射。 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性反射影响 功能将被研究。 颈动脉压力感受器将 其特征在于使用离体和灌注的颈动脉窦 在麻醉犬和骨骼肌受体中的制剂 会被前根刺激和被动肌肉激活 伸展。 实验将定义的操作属性 颈动脉压力感受器反射以及识别频率依赖性 使用传递函数分析反射的特性。 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 使用凝集素结合辣根过氧化物酶（HRP） 用于猫的胫神经 HRP的共定位- NTS阳性神经元和Fos阳性神经元被激活 肌肉收缩将利用 免疫组织化学染色技术。 假设三： 来自骨骼肌受体的传入输入改变了 压力敏感性NTS神经元的兴奋性。 细胞外单- 在控制期间，将从NTS神经元记录单位活动。 压力反射和骨骼肌反射的激活， 包括犬科动物和猫科动物。 这些主要焦点 研究的目的是确定差异尖峰放电 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 从这些实验将提供新的信息， 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枢机制 改变心血管功能动脉压力反射控制 无论是健康还是疾病。

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.