Anatomical Specializations of the Human Pharynx

描述(由申请人提供)：此次更新是对先前申请的扩展，新的重点是探索咽扩张器(膝舌肌，GG)、咽缩肌(PC)、上食道括约肌(UES)和腭肌的解剖和生化特化：1)0-3岁和70-85岁的人类；2)特发性帕金森氏病(IPD)的病理人类标本；3)成年猕猴。这一应用的长期目标是提高我们对上呼吸道功能的神经肌肉控制以及导致吞咽困难和阻塞性睡眠呼吸暂停的机制的了解，以努力开发治疗这两种危及生命的疾病的新疗法。咽肌在维持上呼吸道通畅和咽部吞咽方面起着至关重要的作用。这些肌肉的功能障碍与上呼吸道疾病的发生有关。然而，这些疾病的发病机制仍然知之甚少。我们的初步研究表明，成人的GG被分为慢的水平和快的斜室。PCs和UES由分别由IX和X神经支配的慢内层和快外层组成。有趣的是，PC中的组织化学定义的纤维层随着年龄的增长而变得模糊。另一个重要的发现是，成人咽肌含有表达不寻常的肌球蛋白重链(MHC)亚型(慢紧张型和α-心型)的肌纤维，主要集中在PC的慢水平GG和慢内层。基于这些新的观察结果，我们假设成人的咽肌是由于功能需求的结果而特化的，不同年龄段的正常人之间、正常成人与IPD之间、人类与非人灵长类之间存在着咽肌纤维类型和MHC组成的差异。这些假设将通过以下两个具体目标进行检验。具体目标1是使用当前的解剖学和组织化学标准来确定GG、PC、UES和腭肌中的神经肌肉区段。肌肉组织、神经供应模式、运动终板的带状模式和类型，以及纤维类型的分布将通过全套神经染色(即Sihler‘s染色)、乙酰胆碱酯酶和银染色法以及肌原纤维ATPase染色来确定。具体目标2是研究每一块肌肉和/或隔室中肌肉纤维的内在特性。使用免疫细胞化学、全肌和/或单纤维电泳法和免疫印迹技术，可以检测到特定肌肉和/或肌室中肌肉纤维中的主要和不寻常的MHC亚型。将使用酶组织化学方法研究基于MHC的各种类型的纤维在每个肌肉和/或隔室中的代谢能力。总体而言，拟议的研究将提供有关年龄相关、物种依赖和病理诱导的咽肌神经肌肉特性变化的重要数据。这些知识将加强我们对神经肌肉控制咽部吞咽、言语和呼吸的解剖学和生化基础的理解。这些数据可能有助于指导旨在使用植入式咽肌神经刺激器缓解睡眠期间吞咽困难和呼吸道阻塞的治疗策略。

DESCRIPTION (provided by applicant): This renewal represents an expansion of the previous application with a new focus on exploring the anatomical and biochemical specializations of the pharyngeal dilator (genioglossus, GG), pharyngeal constrictors (PCs), upper esophageal sphincter (UES) and palatal muscles in: 1) 0-3 years old and 70-85 years old humans; 2) pathological human specimens with idiopathic Parkinson's disease (IPD); and 3) adult macaque monkey. The long-term goal of this application is to improve our understanding of the neuromuscular control of the upper airway functions and of the mechanisms causing dysphagia and obstructive sleep apnea in an effort to develop novel therapies for treating both life-threatening disorders. The pharyngeal muscles play vital roles in maintenance of upper airway patency and pharyngeal swallowing. Dysfunction of these muscles is related to the occurrence of upper airway disorders. However, the pathogenesis of these disorders remains poorly understood. Our preliminary studies showed that the adult human GG was divided into slow horizontal and fast oblique compartments. The PCs and UES were composed of a slow inner layer and a fast outer layer which were innervated by the IX and X nerves, respectively. It is interesting to note that the histochemically defined fiber layers in the PCs were obscured with aging. Another important finding was that the adult pharyngeal muscles contained muscle fibers expressing unusual myosin heavy chain (MHC) isoforms (slow-tonic and alpha-cardiac) which were concentrated predominantly in the slow horizontal GG and slow inner layer of the PCs. Based on these novel observations, we hypothesize that the adult human pharyngeal muscles have been specialized as a result of functional demands and that differences in the fiber type and MHC composition in the pharyngeal muscles exist between different age groups of normal humans, between normal adult human and IPD, and between human and non-human primates. The hypotheses will be tested with the following 2 specific aims. Specific Aim 1 is to determine the neuromuscular compartments within the GG, PCs, UES, and palatal muscles using current anatomical and histochemical criteria. The muscular organization, nerve supply patterns, banding patterns and types of the motor endplates, and fibertype distribution will be determined using whole-mount nerve staining (i.e., Sihler's stain), acetylcholinesterase and silver stain, and myofibrillar ATPase staining. Specific Aim 2 is to study the intrinsic properties of the muscle fibers in each of the muscles and/or compartments. The major and unusual MHC isoforms in muscle fibers in a given muscle and/or compartment will be detected using immunocytochemistry, whole muscle and/or single fiber electrophoresis, and immunoblotting techniques. The metabolic capacity of the MHC-based various fiber types in each muscle and/or compartment will be studied using enzyme-histochemical methods. Overall, the proposed studies will provide important data about the age-related, species-dependent and pathologically induced changes in the neuromuscular properties of the pharyngeal muscles. This knowledge will enhance our understanding of the anatomical and biochemical basis of the mechanisms involved in neuromuscular control of the pharyngeal swallowing, speech and respiration. The data may help to guide treatment strategies that are aimed at using implantable pharyngeal muscle nerve stimulators to alleviate dysphagia and airway obstruction during sleep.