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）：慢性内脏超敏反应是许多使人衰弱的人类综合症的常见特征，通常发生在炎症后。由于发炎组织与支配这些结构的主要感觉神经元之间的相互作用，已经提出了这种超敏反应。在上一个资金期间，我们发现内脏器官（结肠，膀胱，胰腺和胃）被表达TRPV1和/或TRPA1的传入密切支配，这两个通道已被证明是炎症性痛觉过敏所必需的。我们还发现，GDNF生长因子家族的所有成员都可以像NGF一样使原发性神经元敏感，并且这些生长因子在低剂量下的增强性比NGF产生了更大的增强。该应用程序生成的初步数据表明，皮肤或内脏结构的炎症会导致GDNF家族成员的mRNA显着增加。使用我们的离体生理制剂，我们发现结肠至少由两个功能上离散的神经元群体支配，并且TRPV1仅在先前被鉴定为机械敏感的高阈值，高摄影剂的种群中表达。因此，提出的研究的一般假设是，内脏的痛觉过敏是通过在TRPV1/TRPA1中选择性提高的敏感性提高的，表达内脏伤害感受器的种群，并且至少部分地通过发炎组织中生长因子的变化来调节这一点。我们的总体假设将以三个具体的目的进行检验：SA1：测试假说，即结肠和膀胱的超敏反应伴随着GDNF生长因子的上调，并且这些生长因子可以使鉴定，分离的，内脏的敏感性敏感。实时PCR和西方分析将用于确认炎症性损伤后结肠和膀胱中生长因子表达的变化。将测定脊柱感觉神经节的变化TRPV1，TRPA1，TRKA，RET和GFR11-3。钙成像将用于确定GDNF家族成员如何影响从Naove小鼠和带有发炎器官的小鼠分离的神经元中鉴定出的，解离的结肠和膀胱传入的反应特性。 SA2：测试新生儿或成人炎症的假设在TRPV1阳性传入中特别具有过敏性。我们已经开发了一种新型的离体制剂，该制剂允许来自完整内脏传入的细胞内记录。我们将使用这种范式来研究幼稚和发炎的结肠和膀胱传入。我们将确定一种器官的炎症是否在另一种器官中产生过敏性，以及新生儿损伤是否会导致成人神经元的长期变化。 SA3：检验假设，即在体内诱导内脏性超敏反应所必需的artemin响应传入。我们实验室最令人兴奋的发现之一是，有大量的内脏伤害感受器表达了GFR13，TRKA，TRPV1和TRPA1的组合。我们将使用专门针对这些神经元的细胞毒素来确定是否可以用来消融这些神经元以预防或反向慢性内脏疼痛。公共卫生相关性：腹部，胸腔和骨盆器官疼痛是患者访问美国医生办公室的第一原因。这些器官由不同类型的感觉神经元支配。这些研究的目的是确定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消融。