Understanding the spinal circuitry of cold

了解寒冷的脊髓回路

• 批准号: 10063581
• 负责人: Tayler Sheahan
• 金额: $ 10.21万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-12-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10063581
• 关键词: Address; Alleles; Architecture; Behavioral; Behavioral Assay; Brain; Cations; Cells; Classification; Collaborations; Cutaneous; Data; Electrophysiology (science); Esthesia; Felis catus; Fellowship; Foundations; Future; Genetic; Goals; Health; Histology; Hypersensitivity; Impairment; K-Series Research Career Programs; Knowledge; Label; Left; Mechanics; Mediating; Modality; Morphology; Mus; Nervous system structure; Neuraxis; Neurokinin A; Neurons; Neuropeptide Receptor; Pain; Pain Clinics; Pain Research; Pathologic; Pattern; Physiologic Thermoregulation; Population; Positioning Attribute; Preparation; Process; Research; Role; Sensory; Spinal; Spinal Cord; Spinal cord posterior horn; Stimulus; Substance P; Substance P Receptor; Synapses; TRP channel; Temperature; Testing; Tetrodotoxin; Tissues; Training; base; behavioral response; biocytin; career development; disabling symptom; effective therapy; experimental study; extreme temperature; neural circuit; optogenetics; painful neuropathy; patch clamp; response; somatosensory; success

Cutaneous thermosensation is critical for detecting and avoiding potentially harmful environmental temperatures, as well as thermoregulation. This mechanism frequently goes awry under neuropathic pain conditions, manifesting as cold hypersensitivity, a condition in which normally cool input is perceived as painfully cold. A limited understanding of how cold stimuli are encoded in the nervous system has left this debilitating condition poorly managed. Recent studies suggest that cold input is conveyed from the periphery to the central nervous system by a population of primary afferents that express the temperature-sensitive cation channel TRPM8. However, the neural circuits through which this information is processed in the spinal cord and conveyed to the brain remain almost completely unknown. To address this fundamental gap in knowledge, this proposal will dissect the neural circuitry that encodes cold stimuli through a combination of behavioral, electrophysiological and morphological approaches. Based on our preliminary studies, we believe that cold input is conveyed from the spinal cord to the brain by a subset of neurokinin 1 receptor (NK1R)-expressing spinoparabrachial projection neurons. To investigate this possibility, our lab recently generated a NK1R-CreER allele, thereby providing us with genetic access to label and manipulate the activity of NK1R neurons. This proposal will test the hypothesis that cold input is conveyed from the spinal cord to the brain by a subset of morphologically distinct NK1R neurons that receive synaptic input (direct or indirect) from cold-sensing, TRPM8 primary sensory afferents. Aim 1 will investigate whether NK1R spinal projection neurons are required for aversion to cold using behavioral assays. Aim 2 will dissect the circuitry between TRPM8 primary afferents and NK1R spinal projection neurons that respond to cold stimuli using electrophysiology and optogenetic approaches in combination with our ex vivo somatosensory preparation. Aim 3 will determine the morphology of cold-selective spinal projection neurons by using histology to reconstruct cell architecture within the spinal cord dorsal horn. These experiments will establish the basic spinal circuitry that mediates cold input, thereby providing a framework from which to investigate changes in circuitry that underlie cold hypersensitivity in future studies. The success of this multifaceted fellowship training plan, which includes activities for scientific and career development, will be aided by the scientific expertise, collaboration, and educational opportunities offered by the Pittsburgh Center for Pain Research.

皮肤热感觉对于检测和避免潜在有害的环境温度至关重要， 以及体温调节。这种机制在神经性疼痛条件下经常出错， 表现为冷过敏，在这种情况下，通常冷的输入被认为是令人痛苦的冷。一个 对冷刺激如何在神经系统中编码的了解有限，导致了这种令人衰弱的状况 管理不善。最近的研究表明冷输入是从外周神经传递到中枢神经的 系统由表达温度敏感的阳离子通道 TRPM8 的初级传入细胞群组成。 然而，在脊髓中处理这些信息并将其传送到大脑的神经回路 大脑仍然几乎完全未知。为了解决这一基本知识差距，该提案将 通过行为学、电生理学的结合来剖析编码冷刺激的神经回路 和形态学方法。根据我们的初步研究，我们认为冷输入是从 通过表达神经激肽 1 受体 (NK1R) 的脊髓旁臂投射子集从脊髓到大脑 神经元。为了研究这种可能性，我们的实验室最近生成了 NK1R-CreER 等位基因，从而为我们提供了 具有标记和操纵 NK1R 神经元活动的遗传能力。该提案将检验假设 冷输入是通过形态不同的 NK1R 神经元子集从脊髓传递到大脑的 从冷感 TRPM8 初级感觉传入接收突触输入（直接或间接）。目标1将 使用行为分析研究 NK1R 脊髓投射神经元是否是厌恶寒冷所必需的。 目标 2 将剖析 TRPM8 初级传入神经元和 NK1R 脊髓投射神经元之间的电路 使用电生理学和光遗传学方法结合我们的离体反应冷刺激 体感准备。目标 3 将通过以下方式确定冷选择性脊髓投射神经元的形态 使用组织学重建脊髓背角内的细胞结构。这些实验将建立 介导冷输入的基本脊髓回路，从而提供了一个研究框架 在未来的研究中，冷过敏背后的电路变化。这一多方面的成功 研究金培训计划，其中包括科学和职业发展活动，将得到 匹兹堡疼痛中心提供的科学专业知识、合作和教育机会 研究。