Nitrergic Neuro-smooth Muscle Transmission in the Gut

肠道中的氮能神经平滑肌传递

• 批准号: 7163430
• 负责人: Raj K Goyal
• 金额: $ 28.74万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7163430
• 关键词: Action Potentials; Antisense Oligonucleotides; Binding; Calcium; Calcium Signaling; Cell membrane; Clinical Treatment; Coal; Condition; Cytosol; Disease; Docking; Dyes; Exocytosis; Fluorescent Dyes; Gases; Gastrointestinal Motility; Genetically Engineered Mouse; Interruption; Interstitial Cell of Cajal; Intramuscular; Life; Localized; Measures; Mediating; Membrane; Membrane Potentials; Membrane Proteins; Microscopy; Microtubules; Modeling; Motor; Mus; N-Type Calcium Channels; Nerve; Neuromuscular Junction; Neurotransmitters; Nitric Oxide; Nitroxidergic Nerves; Pathogenesis; Peptides; Phosphorylation; Physiology; Planning Techniques; Play; Production; Protein Dephosphorylation; Proteins; Regulation; Research Personnel; Role; Secretory Vesicles; Signal Pathway; Signal Transduction; Site; Smooth Muscle; Smooth Muscle Myocytes; Sodium; Source; Structure; Synapses; Techniques; Testing; Thinking; Time; Tissues; Varicosity; Vasoactive Intestinal Peptide Receptors; autocrine; controlled release; dimer; immunoreactivity; inhibitor/antagonist; interstitial cell; motility disorder; multi-photon; neuromuscular transmission; neurotransmission; novel; receptor; response; tetrahydrobiopterin; transmission process

DESCRIPTION (provided by applicant): A large body of evidence suggests that nitric oxide (NO) gas play a key role in nonadrenergic noncholinergic (NANC) inhibitory neuro-smooth muscle transmission throughout the body including the gut. Clinically, deficiency of nitrergic transmission has been shown to be responsible for many major gastrointestinal motility disorders. However, several important questions regarding nitrergic neurotransmission remain unanswered. For example, the precise site(s) of production of NO at the neuro-smooth muscle junctions, including the prejunctional nerve varicosities, the postjunctional smooth muscle cells or the intramuscular type of interstitial cells of Coal (ICC-IM) remain undefined. Some investigators believe that NO produced in the postjunctional structures is essential in the neuromuscular transmission. It is also unclear how this highly diffusible gas can fulfill the function of a neurotransmitter that requires highly controlled release. The release of a classical neurotransmitter is regulated by exocytosis of a small fraction of the secretory granules that are docked onto the plasma membrane. However, NO is not stored in the secretory granules and is thought to be produced on demand during the neurotransmission. The nerve varicosities that contain nNOS also contain peptide VIP, however, the role VIP in nitrergic neuro smooth muscle neurotransmission is controversial. We propose models of regulation of nNOS and an intermediary role of VIP in nitrergic neurotransmission. To test these models we plan to utilize: (1) a novel technique using fluorescent dye markers and multi-photon microscopy to visualize NO and calcium signals in real-time in live nerve varicosities and other structures at the neuromuscular junctions; (2) immunocytological studies using multi-photon microscopy to localize the proteins that may be involved in cycling of nNOS from catalytically inactive to catalytically active forms; (3) intracellular recordings of the nitrergic inhibitory junction potentials. Using the above techniques, we plan to study the effects of pharmacological manipulations to test the proposed models. These studies will help define:(1) whether during the neurotransmission NO is produced in the nerve varicosities and also in the postjunctional smooth muscle cells or ICC-IM; (2) the regulation of nNOS that permits NO gas to function as a neurotransmitter; (3) the intermediary role of VIP and its unique receptor subtype in nitrergic neurotransmission. This information may help in understanding physiology, and the pathogenesis and rational treatment of clinical disorders due to deficiency of nitrergic neuro-smooth muscle transmission.

描述（由申请人提供）：大量证据表明，一氧化氮 (NO) 气体在包括肠道在内的全身非肾上腺素能非胆碱能 (NANC) 抑制性神经平滑肌传递中发挥着关键作用。临床上，氮能传输缺陷已被证明是许多主要胃肠动力障碍的原因。然而，关于氮能神经传递的几个重要问题仍未得到解答。例如，在神经平滑肌连接处产生 NO 的精确位点，包括交界前神经静脉曲张、交界后平滑肌细胞或煤间质细胞的肌肉内类型 (ICC-IM) 仍然不确定。一些研究人员认为，连接后结构中产生的一氧化氮对于神经肌肉传递至关重要。目前还不清楚这种高度扩散的气体如何实现需要高度控制释放的神经递质的功能。经典神经递质的释放是通过停靠在质膜上的一小部分分泌颗粒的胞吐作用来调节的。然而，NO 并不储存在分泌颗粒中，而是被认为是在神经传递过程中按需产生的。含有nNOS的神经静脉曲张也含有肽VIP，然而，VIP在氮能神经平滑肌神经传递中的作用存在争议。我们提出了 nNOS 调节模型以及 VIP 在氮能神经传递中的中介作用。为了测试这些模型，我们计划利用：（1）一种新技术，使用荧光染料标记和多光子显微镜来实时可视化活体神经静脉曲张和神经肌肉接头处其他结构中的 NO 和钙信号； (2) 使用多光子显微镜进行免疫细胞学研究，定位可能参与 nNOS 从催化非活性形式到催化活性形式循环的蛋白质； (3) 氮能抑制连接电位的细胞内记录。使用上述技术，我们计划研究药理学操作的效果以测试所提出的模型。这些研究将有助于明确：(1)在神经传递过程中，NO是否在神经静脉曲张中产生，并且也在结后平滑肌细胞或ICC-IM中产生； (2) 调节 nNOS，使 NO 气体发挥神经递质的作用； (3)VIP及其独特的受体亚型在氮能神经传递中的中介作用。这些信息可能有助于了解由于氮能神经平滑肌传递缺陷引起的临床疾病的生理学、发病机制和合理治疗。