Ionic Mechanisms Underlying Dorsal Root Ganglion Excitability

背根神经节兴奋性的离子机制

基本信息

批准号：
8661798
负责人：
Arindam Bhattacharjee
金额：
$ 33.39万
依托单位：
STATE UNIVERSITY OF NEW YORK AT BUFFALO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8661798
关键词：
Affect Afferent Neurons Analgesics Attenuated Behavior Behavioral Assay Binding Biochemical Cells Complex Consensus Diabetes Mellitus Diabetic Neuropathies Diabetic mouse Esthesia Exhibits Family Functional disorder Future Gene Expression Genes Glucose Goals Hyperalgesia Immunohistochemistry Ions Kinetics Knockout Mice Label Lead Link Marshal Metabolic Mitogen Activated Protein Kinase 1 Modeling Molecular Mus Nervous system structure Neurons Neuropathy Numbness Outcome Pain Pathway interactions Perception Peripheral Nervous System Diseases Persistent pain Phenotype Phosphorylation Phosphorylation Inhibition Phosphorylation Site Physicians Physiological Population Potassium Potassium Channel Primary Lesion Process Property Proteins Rattus Reaction Recombinants Reflex action Regulation Research Project Grants Role Sensory Signal Transduction Site-Directed Mutagenesis Societies Sodium Spinal Ganglia Stimulus Streptozocin Symptoms System Techniques Testing Ubiquitination Unemployment Visit Western World Work Xenopus oocyte allodynia chronic pain design diabetic experience human MAPK14 protein improved neuronal excitability novel pain behavior painful neuropathy response treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Pain sensation in neuropathic pain is complex consisting of weakness, sensory deficits and numbness, reflex changes, abnormal sensations that occur either spontaneously or in reaction to external stimuli, hyperalgesia and allodynia. Perturbations in dorsal root ganglion (DRG) neuron excitability are key in precipitating neuropathic pain, especially during diabetes, the most common cause of neuropathic pain. During diabetes, the p38 mitogen-activated protein kinase (p38MAPK) signaling system is activated and when this pathway is inhibited, diabetes-induced neuropathic pain is attenuated. However, the major ion conductances involved in the neuropathic process of DRG neurons are unclear. DRG neurons possess high levels of a novel, understudied family of potassium channels called sodium-activated potassium channels (KNa). Our previous work has shown that KNa is a considerable component of the outward potassium current and is responsible for firing accommodation in DRG neurons. When we experimentally reduce the expression of these channels in DRG neurons, it produces hyperexcitability that resembles neuropathic neurons. There are two genes encoding these channels, Slack and Slick. In heterologous expression systems, the Slick and Slack subunits can co-assemble to form heteromeric channels systems with very slow activation kinetics ideal for controlling firing accommodation. Moreover, homomeric Slick channels appear to be subject to Nedd4l-dependent ubiquitination, suggesting that Slack/Slick heteromeric channels are the preferred configuration of native KNa channels. Slack and Slick also have p38MAPK consensus phosphorylation sites proximal to the sodium binding/gating region of the channels. A decrease in KNa channel activity likely ensues after diabetes-activated p38MAPK signaling. Since diabetes also affects transcriptional activities, we expect to find long-term changes in KNa channel expression in neurons. Using electrophysiological, biochemical, molecular, pain behavioral assays and a previously uncharacterized Slick knockout mouse, we will test the hypotheses: heteromeric KNa channels constrain sensory neuron hyperexcitability and neuropathic pain is associated with decreased KNa channel activity in DRG neurons. The specific aims are (1) To study the regulation of DRG KNa channels by p38MAPK (2) To investigate the subunit properties of KNa channels in DRG neurons (3) To study neuronal KNa channel activity during diabetes and compare pain behavior to Slick knockout mice. This research project will assess the involvement of KNa channels in the diabetic neuropathy.

描述（由申请人提供）：神经性疼痛中的疼痛感觉是复杂的，包括无力，感觉缺陷和麻木，反射变化，自发或对外部刺激，痛力和异常性痛的反应的异常感觉。背根神经节（DRG）神经元兴奋性的扰动是导致神经性疼痛的关键，尤其是在糖尿病期间，这是神经性疼痛的最常见原因。在糖尿病期间，p38有丝分裂原激活的蛋白激酶（p38MAPK）信号系统被激活，当抑制该途径时，糖尿病引起的神经性疼痛会减弱。然而，尚不清楚参与DRG神经元神经性过程的主要离子电导。 DRG神经元具有高水平的新型，研究的钾通道家族，称为钠激活的钾通道（KNA）。我们以前的工作表明，KNA是向外钾电流的相当大的组成部分，并且负责在DRG神经元中触发住宿。当我们通过实验减少DRG神经元中这些通道的表达时，它会产生类似于神经性神经元的过度刺激性。有两个编码这些通道的基因：松弛和光滑。在异源表达系统中，光滑和松弛的亚基可以共组装，形成具有非常缓慢的激活动力学的异源通道系统，非常适合控制射击燃料。此外，同源性光滑通道似乎受NEDD4L依赖性泛素化的约束，这表明松弛/光滑的异质通道是天然KNA通道的首选配置。松弛和光滑也具有p38mapk共有的磷酸化位点，靠近通道的钠结合/门控区域。糖尿病激活的p38mapk信号传导后，KNA通道活性可能会减少。由于糖尿病也会影响转录活性，因此我们希望在神经元中发现KNA通道表达的长期变化。使用电生理学，生化，分子，疼痛行为测定和先前未表征的滑基敲除小鼠，我们将测试假设：异脑SKNA通道约束感觉神经元过度刺激性和神经性疼痛与DRG神经元中DRG神经元的降低相关。具体目的是（1）研究p38mapk（2）对DRG KNA通道的调节，以研究DRG神经元中KNA通道的亚基特性（3）（3），以研究糖尿病期间的神经元KNA通道活性并比较疼痛行为在疼痛行为中与光滑的敲除小鼠进行比较。该研究项目将评估KNA通道参与糖尿病神经病。