Purinergic neurotransmission in the gut

肠道内的嘌呤能神经传递

• 批准号: 8446304
• 负责人: James J. Galligan
• 金额: $ 27.89万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8446304
• 关键词: Acetylcholine; Afferent Neurons; Antibodies; Anus; Autonomic nervous system; Biological; Blood flow; Cell physiology; Cells; Chemicals; Chronic; Code; Colon; Complex; Constipation; Data; Disease; Drug usage; Elements; Enteral; Enteric Nervous System; Functional disorder; Gastrointestinal Motility; Gastrointestinal tract structure; In Vitro; Interneurons; Ion Channel; Knockout Mice; Methods; Modeling; Molecular; Mus; Muscle; Muscle Contraction; Muscle Tonus; Muscle relaxation phase; Mutant Strains Mice; Myenteric Plexus; Nerve; Neurons; Neurotransmitters; Nicotinamide adenine dinucleotide; Nitric Oxide; Nucleotides; Oral; Pathway interactions; Pattern; Pharmaceutical Preparations; Physiological; Population; Potassium Channel; Property; Reflex action; Relaxation; Role; Smooth Muscle; Smooth Muscle Myocytes; Synapses; Synaptic Transmission; Testing; Visceral pain; cell motility; common treatment; gastrointestinal; in vivo; insight; large-conductance calcium-activated potassium channels; motility disorder; motor control; nerve supply; neural circuit; neurochemistry; neuromuscular transmission; neurotransmission; neurotransmitter release; postsynaptic; presynaptic; receptor; selective expression

DESCRIPTION (provided by applicant): The enteric nervous system (ENS) is the division of the autonomic nervous system that resides within the gut wall. The ENS controls gastrointestinal (GI) motility, secretion and local blood flow. The ENS can perform these complex functions because it contains all the neuronal elements (sensory neurons, interneurons and motorneurons) required for GI reflexes and integration. The ENS contains 14 different types of neurons that release different neurotransmitters. There are also multiple receptors for each neurotransmitter. In addition, synapses in the ENS may be coded by the neurotransmitters released from presynaptic nerve terminals and by receptors expressed by postsynaptic cells. The proposed studies will use intracellular electrophysiological, immunohistochemical and molecular biological methods to study enteric neuromuscular transmission. There are 3 specific aims in this proposal. Specific aim 1 will test the hypothesis that there are two separate populations of inhibitory nerves supplying the muscle layers. One subset uses nitric oxide (NO) as the primary neurotransmitter while the second population is purinergic (ATP and/or b-nicotinamide adenine dinucleotide are the neurotransmitters). These studies will show that release of ATP/b-NAD and NO from nerve terminals is controlled by different Ca2+ channel types. An antibody against the vesicular nucleotide (VNUT) antibody will be used to localize purinergic nerves. These studies will also make use of P/Q type and R-type Ca2+ channel mutant mice. Specific aim 2 will focus on Ca2+ channels expressed by interneurons in the myenteric plexus. Interneurons which project in an oral-anal direction release acetylcholine (ACh) and ATP as fast synaptic transmitters, while neurons that project in an anal-oral direction release ACh. These studies will test the hypothesis that R-, N- and P/Q type Ca2+ channels are expressed by neurons in the orally-projecting pathway while only N- and P/Q type Ca2+ channels are expressed by nerve terminals in the anally-projecting pathway. These studies will also use wild type and P/Q-type and R-type Ca2+ channel mutant mice. Specific aim 3 will focus on K+ channels as regulators of gut smooth muscle tone and neuromuscular transmission in the colon. These studies will make use of a b1 subunit of the large conductance Ca2+-activated K+ (BK) channel knockout mouse. Significance: Disturbances in enteric synaptic mechanisms contribute to GI motility disorders. Changes in the function of enteric neurons and their synapses might also contribute to visceral pain. Therefore, a more complete understanding of enteric neural circuits and synaptic transmission would provide insights into the pathophysiology of GI motility disorders. This information would help to develop new drug treatments for common motility disorders.

描述（由申请人提供）：肠神经系统（ENS）是位于肠壁内的自主神经系统的划分。 ENS控制胃肠道（GI）运动，分泌和局部血流。 ENS可以执行这些复杂功能，因为它包含GI反射和整合所需的所有神经元元素（感觉神经元，中间神经元和运动神经元）。 ENS包含14种不同类型的神经元，它们释放不同的神经递质。每个神经递质也有多个受体。此外，ENS中的突触可以由从突触前神经末端和突触后细胞表达的受体释放的神经递质编码。拟议的研究将使用细胞内电生理学，免疫组织化学和分子生物学方法来研究肠神经肌肉传播。该提案中有3个具体目标。具体目标1将检验以下假设：有两个单独的抑制神经供应肌肉层。一个子集使用一氧化氮（NO）作为主要的神经递质，而第二个群体是嘌呤能（ATP和/或B-奈辛酰胺腺苷二核苷酸是神经递质）。这些研究将表明，ATP/B-NAD的释放和神经末端的NO释放由不同的Ca2+通道类型控制。针对囊泡核苷酸（Vnut）抗体的抗体将用于定位嘌呤能神经。这些研究还将利用P/Q类型和R型Ca2+通道突变小鼠。特定的目标2将重点放在肌丛中中间神经元表达的Ca2+通道上。沿口腔 - 分析释放乙酰胆碱（ACH）和ATP的中间神经元作为快速突触发射机，而神经元的神经元在肛门口径方向释放ACH中进行。这些研究将检验以下假设：R-，N-和P/Q型Ca2+通道在口腔注射途径中的神经元表达，而仅N-和P/Q型Ca2+通道仅由神经末端在肛门预注射途径中表达。这些研究还将使用野生型和P/Q-Type和R型Ca2+通道突变小鼠。特定的目标3将集中于K+通道作为肠平滑肌肉张力和神经肌肉传播的调节剂。这些研究将利用大电导Ca2+活化的K+（BK）通道基因敲除小鼠的B1亚基。意义：肠道突触机制的干扰导致胃肠道运动障碍。肠神经元及其突触功能的变化也可能导致内脏疼痛。因此，对肠神经回路和突触传播的更完整了解将为胃肠道运动障碍的病理生理学提供见解。这些信息将有助于开发针对常见运动障碍的新药物治疗。