Functional Analysis of Distinct Nociceptor Populations

描述（由申请人提供）：触觉对日常生活至关重要。此外，对触摸的超敏反应是与慢性神经性疼痛和持续性炎性疼痛相关的常见问题。尽管它的重要性，令人惊讶的是，很少有人知道的分子和细胞机制的基础上触摸感觉，以及是否不同的转导机制介导无害与痛苦的机械刺激。一个有前途的机械转导候选者是瞬时受体电位锚蛋白1（TRPA 1）。大量证据表明，TRPA1有助于躯体感觉神经元中的机械转导以及组织炎症或神经损伤后它们对机械刺激的敏感化。此外，有争议的证据表明，TRPA1参与神经损伤和炎症后的冷传导和冷致敏。然而，一些重要的问题仍然存在，关于TRPA1在机械传导和冷传导中的特定功能作用。1)来自我们实验室和其他实验室的证据表明，TRPA 1由非神经元角质形成细胞以及感觉神经末梢表达，但TRPA 1在任一细胞类型中对皮肤初级传入神经元对机械力或低温的净反应的贡献是未知的。本提案中的实验将使用两种新的转基因小鼠品系，其中选择性地从角质形成细胞或感觉神经元中删除TRPA1，以确定TRPA1在任一细胞类型中对机械和冷刺激的行为和初级传入纤维反应的贡献。2)感觉神经元或角质形成细胞中的TRPA1是否介导质膜对机械力或冷的反应尚不清楚。本申请中的实验将在全细胞膜片钳记录期间使用创新的定量局灶性机械刺激器，以确定TRPA 1对感觉神经元和角质形成细胞膜中机械电流的贡献。3)机械性超敏反应是与神经性疼痛和炎性疼痛相关的最常见的破坏性症状之一。TRPA1对神经损伤或炎症后初级传入纤维对机械和冷刺激的敏感性的贡献尚不清楚。本提案中的实验将确定感觉神经元或角质形成细胞中的TRPA1是否介导神经性疼痛模型和持续性外周炎症模型中发生的机械或冷致敏。在这项提议中，使用细胞、梳理纤维和行为测定的互补特异性目的将提供一种多方面的方法来鉴定TRPA 1在正常组织中的感觉转导中以及在神经性和炎症性疼痛期间的功能作用。 公共卫生相关性：触觉对日常生活至关重要。慢性神经性疼痛和持续性炎性疼痛综合征患者对触摸和低温异常敏感。我们的目标是确定离子通道瞬时受体电位锚蛋白1（TRPA 1）在正常皮肤中的触觉和冷传导中的作用，并确定其在神经性和炎症性疼痛模型中的作用。

DESCRIPTION (provided by applicant): Touch sensation is essential to daily life. Further, hypersensitivity to touch is a frequent problem associated with chronic neuropathic pain and persistent inflammatory pain. Despite its importance, amazingly little is known about the molecular and cellular mechanisms underlying touch sensation and whether different transduction mechanisms mediate innocuous versus painful mechanical stimuli. A promising mechanotransduction candidate is the Transient Receptor Potential Ankyrin 1 (TRPA1). Significant evidence suggests that TRPA1 contributes to mechanotransduction in somatosensory neurons and their sensitization to mechanical stimuli after tissue inflammation or nerve injury. Further, controversial evidence suggests that TRPA1 is involved in cold transduction and cold sensitization after nerve injury and inflammation. A number of important questions remain, however, about the specific functional roles of TRPA1 in mechanotransduction and cold transduction. 1) Evidence from our laboratory and others indicates that TRPA1 is expressed by non- neuronal keratinocytes, as well as sensory nerve terminals, yet the contribution of TRPA1 in either cell type to the net responses of cutaneous primary afferent neurons to mechanical force or cold temperatures is unknown. Experiments in this proposal will use two new lines of transgenic mice where TRPA1 is selectively deleted from either keratinocytes or sensory neurons to determine the contribution of TRPA1 in either cell type to behavioral and primary afferent fiber responses to mechanical and cold stimuli. 2) Whether TRPA1 in sensory neurons or keratinocytes mediates the plasma membrane response to mechanical force or cold is not clear. Experiments in this application will use an innovative, quantitative focal mechanical stimulator during whole cell patch clamp recordings to identify the contribution of TRPA1 to mechanical currents in the membrane of sensory neurons and keratinocytes. 3) Mechanical hypersensitivity is one of the most frequent, devastating symptoms associated with neuropathic and inflammatory pain. The contribution of TRPA1 to sensitization of primary afferent fibers to mechanical and cold stimuli after nerve injury or inflammation is unknown. Experiments in this proposal will determine whether TRPA1 in either sensory neurons or keratinocytes mediates the mechanical or cold sensitization that occurs in a model of neuropathic pain, and a model of persistent peripheral inflammation. In this proposal, complimentary Specific Aims using cellular, teased fiber and behavioral assays will provide a multifaceted approach to identify functional roles of TRPA1 in sensory transduction in normal tissue, and during neuropathic and inflammatory pain. PUBLIC HEALTH RELEVANCE: Touch sensation is essential to daily life. Abnormal hypersensitivity to touch and to cold temperature occurs in patients with chronic neuropathic pain and persistent inflammatory pain syndromes. Our goals are to determine the roles of the ion channel Transient Receptor Potential Ankyrin 1 (TRPA1) in touch and cold transduction in normal skin, and to identify its roles in neuropathic and inflammatory pain models.