Characterization and Plasticity of Visceral Nociceptors

内脏伤害感受器的特征和可塑性

• 批准号: 7761314
• 负责人: BRIAN M DAVIS
• 金额: $ 32.81万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7761314
• 关键词: Abdomen; Ablation; Adult; Affect; Afferent Neurons; Animal Model; Biological Assay; Bladder; Buffers; Calcium; Cells; Chemosensitization; Chest; Chronic; Colon; Cutaneous; Cystitis; Data; Development; Dose; Esthesia; Family; Family member; Funding; GDNF gene; GDNF receptors; Genus Cola; Goals; Growth Factor; Growth Factor Receptors; Hour; Human; Hyperalgesia; Hypersensitivity; Image; Inflammation; Inflammatory; Injection of therapeutic agent; Injury; Ion Channel; Link; Messenger RNA; Modeling; Mus; Neonatal; Nerve Growth Factors; Neurons; Nociception; Nociceptors; Organ; Pain; Pancreas; Pancreatitis; Patients; Pelvis; Perfusion; Persistent pain; Physiological; Population; Preparation; Property; Recovery; Sensory Ganglia; Series; Spinal; Spinal Ganglia; Staining method; Stains; Stimulus; Stomach; Structure; Syndrome; TRPV1 gene; Testing; Time; Tissues; Toxin; Up-Regulation; Visceral; Visceral Afferents; Visceral pain; Visit; in vivo; in vivo Model; member; neonate; neurobiotin; neurochemistry; neurturin; novel; prevent; public health relevance; receptor expression; research study; response

DESCRIPTION (provided by applicant): Chronic visceral hypersensitivity is a common feature of a number of debilitating human syndromes, often occurring following inflammation. This hypersensitivity has been proposed to develop due to interactions between inflamed tissues and the primary sensory neurons that innervate these structures. In the previous funding period we found that visceral organs (colon, bladder, pancreas and stomach) are densely innervated by afferents expressing TRPV1 and/or TRPA1, two channels that have been shown to be required for development of inflammatory hyperalgesia. We also found that all members of the GDNF family of growth factors could, like NGF, sensitize primary sensory neurons and that these growth factors produced greater potentiation at lower doses than NGF. Preliminary data generated for this application show that inflammation of cutaneous or visceral structures induces significant increases in mRNA for GDNF family members. Using our ex vivo physiological preparation we found that the colon is innervated by at least two functionally discrete populations of neurons and that TRPV1 was exclusively expressed in a population that had previously been identified as mechanically sensitive, high threshold, nociceptors. Thus, the general hypothesis of the proposed studies is that visceral hyperalgesia is initiated by increased sensitivity selectively in the TRPV1/TRPA1- expressing population of visceral nociceptors and that this is regulated, at least in part, by changes in growth factors in the inflamed tissues. Our general hypothesis will be tested in three Specific Aims: SA1: Test the hypothesis that hypersensitivity of colon and bladder are accompanied by upregulation of the GDNF family of growth factors and that these growth factors can sensitize identified, dissociated, visceral afferents. Real-time PCR and Western analysis will be used to confirm changes in growth factor expression in colon and bladder following inflammatory insult. Spinal sensory ganglia will be assayed for changes in TRPV1, TRPA1, trkA, ret and GFR11-3. Calcium imaging will be used to determine how GDNF family members affect response properties of identified, dissociated colonic and bladder afferents in neurons isolated from naove mice and mice with inflamed organs. SA2: Test the hypothesis that neonatal or adult inflammation produces hypersensitivity specifically in TRPV1-positive afferents. We have developed a novel ex vivo preparation that allows intracellular recordings from intact visceral afferents. We will use this paradigm to study naive and inflamed colon and bladder afferents. We will determine if inflammation of one organ produces hypersensitivity in another, and whether neonatal injury produces long-term changes in adult neurons. SA3: Test the hypothesis that artemin responsive afferents are required for induction of visceral hypersensitivity in vivo. One of the most exciting findings from our lab is that there is a significant population of visceral nociceptors that express a combination of GFR13, trkA, TRPV1 and TRPA1. We will use a cell toxin that specifically targets these neurons to determine if it can be used to ablate these neurons to prevent or reverse chronic visceral pain. PUBLIC HEALTH RELEVANCE: Abdominal, thoracic and pelvic organ pain is the number one reason for patient visits to doctor's offices in the US. These organs are innervated by different types of sensory neurons. The goal of these studies is to determine if a specific type of neuron is responsible for persistent pain sensations and whether these can be ablated without affecting normal organ function.

描述（由申请人提供）：慢性内脏过敏是许多衰弱性人类综合征的共同特征，通常发生在炎症之后。这种超敏反应是由于炎症组织和支配这些结构的初级感觉神经元之间的相互作用而产生的。在之前的资助期内，我们发现内脏器官（结肠、膀胱、胰腺和胃）被表达TRPV1和/或TRPA1的传入神经密集支配，这两个通道已被证明是炎性痛觉过敏的发展所必需的。我们还发现，GDNF生长因子家族的所有成员都可以像NGF一样，使初级感觉神经元敏感，并且这些生长因子在较低剂量下比NGF产生更大的增强作用。为该应用生成的初步数据显示，皮肤或内脏结构的炎症诱导GDNF家族成员mRNA显著增加。通过体外生理制备，我们发现结肠至少由两个功能离散的神经元群支配，TRPV1仅在先前被确定为机械敏感、高阈值、伤害感受器的群体中表达。因此，提出的研究的一般假设是，内脏痛觉过敏是由内脏伤害感受器中TRPV1/TRPA1-表达群体选择性地增加敏感性引起的，并且这种敏感性至少在一定程度上受到炎症组织中生长因子变化的调节。我们的一般假设将在三个具体目标中得到验证：SA1：验证结肠和膀胱的超敏性伴随着GDNF生长因子家族的上调，并且这些生长因子可以使已识别的、游离的、内脏传入神经敏感。Real-time PCR和Western分析将证实炎症损伤后结肠和膀胱中生长因子表达的变化。检测脊髓感觉神经节中TRPV1、TRPA1、trkA、ret和GFR11-3的变化。钙成像将用于确定GDNF家族成员如何影响从幼稚小鼠和炎症器官小鼠分离的神经元中已识别的、解离的结肠和膀胱传入事件的反应特性。SA2：验证新生儿或成人炎症特异性地在trpv1阳性传入神经中产生超敏反应的假设。我们已经开发了一种新的离体制剂，允许完整内脏传入的细胞内记录。我们将使用这种模式来研究幼稚和发炎的结肠和膀胱传入事件。我们将确定一个器官的炎症是否会在另一个器官中产生超敏反应，以及新生儿损伤是否会在成年神经元中产生长期变化。SA3：验证体内诱导内脏超敏反应需要青蒿素反应事件的假设。我们实验室最令人兴奋的发现之一是，有大量内脏伤害感受器表达GFR13、trkA、TRPV1和TRPA1的组合。我们将使用一种专门针对这些神经元的细胞毒素来确定它是否可以用来切除这些神经元，以预防或逆转慢性内脏疼痛。公共卫生相关性：在美国，腹部、胸部和盆腔器官疼痛是患者去医生办公室就诊的头号原因。这些器官受不同类型的感觉神经元支配。这些研究的目的是确定一种特定类型的神经元是否负责持续的疼痛感觉，以及这些神经元是否可以在不影响正常器官功能的情况下切除。