Ghrelin Modulation of CaV 2.2 Channels After Spinal Cord Injury

脊髓损伤后 Ghrelin 对 CaV 2.2 通道的调节

• 批准号: 10750130
• 负责人: Hannah J Goudsward
• 金额: $ 3.45万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750130
• 关键词: Acute; Address; Afferent Neurons; Animal Model; Appetite Stimulants; Attenuated; Binding; Biological Models; Calcium; Calcium Channel; Cells; Chemicals; Chest; Cholecystokinin; Chronic; Clinical; Closure by clamp; Coupled; Couples; Cutaneous; Diabetes Mellitus; Disease; Electrophysiology (science); Fiber; Functional disorder; Future; G-Protein-Coupled Receptors; Gastrointestinal Hormones; Gastroparesis; Genetic Transcription; Goals; Health; Heterotrimeric GTP-Binding Proteins; Hormones; Imaging Techniques; Immunohistochemistry; Impairment; In Vitro; Individual; Injury; Knowledge; Ligands; Mechanics; Mediating; Modeling; Molecular; Motor; Motor output; Nerve; Neurons; Nodose Ganglion; Obesity; Outcome; Pathway interactions; Peptides; Peripheral; Polymerase Chain Reaction; Presynaptic Terminals; Quality of life; Rattus; Receptor Activation; Reflex action; Reporting; Reverse Transcription; Role; Scientist; Sensory; Signal Pathway; Signal Transduction; Spinal cord injury; Spinal cord injury patients; Stimulus; Stomach; Structure; Synapses; Techniques; Testing; Training; Vagus nerve structure; Work; afferent nerve; cell motility; comorbidity; experimental study; gastrointestinal; ghrelin; growth hormone secretagogue receptor; improved; in vivo; innovation; insight; mimetics; motility disorder; neuronal cell body; neuronal excitability; neurotransmitter release; patch clamp; pre-clinical; receptor; response; social; therapeutic target; transmission process; voltage

Project Summary Gastrointestinal (GI) dysfunction after spinal cord injury (SCI) is a highly prevalent, but significantly understudied comorbidity that negatively impacts quality of life for individuals with SCI. Increasing evidence suggests impaired vagal activity is a primary cause of upper GI dysfunction after injury. Under normal conditions, gastric reflexes are coordinated by the vagus nerve. The vagus nerve contains both afferent fibers that convey sensory information to central structures and efferent fibers that carry motor output needed for gastric contractions. Previous work in our lab has demonstrated that following injury, vagal afferents are significantly less responsive to chemical stimuli, including the gut peptide ghrelin. Ghrelin is an orexigenic hormone that normally serves to decrease vagal afferent activity and increase gastric motility by binding to the growth hormone secretagogue receptor (GHSR1a), a G protein-coupled receptor, expressed along the vagal afferents. The cellular mechanisms underlying ghrelin’s ability to modulate vagal afferent activity in both healthy and disease states have yet to be fully elucidated. This proposal will utilize an animal model of SCI combined with molecular and imaging techniques, in vitro patch-clamp electrophysiology, and in vivo nerve recordings to identify mechanisms underlying the loss of vagal sensitivity post-SCI. The proposed experiments will investigate the central hypothesis that GHSR1a-mediated inhibition of calcium currents is dysregulated in gastric-projecting nodose ganglia neurons after SCI. Based upon our preliminary observations, we will test the hypothesis with two specific aims. Aim 1 will determine the precise mechanism underlying GHSR1a modulation of voltage-gated Ca2+ channels (CaV2.2 or N-type) in gastric-projecting vagal afferent neurons of naïve rats using whole-cell patch- clamp electrophysiology. Aim 2 will utilize immunohistochemistry, single-cell quantitative reverse transcription polymerase chain reaction (qRT-PCR), electrophysiological techniques, and in vivo nerve recordings to identify whether the GHSR1a-mediated effects of ghrelin on N-type Ca2+ channel currents and gastric vagal afferent excitability are dysregulated following SCI. This proposal will provide critical information regarding how changes to GPCR-mediated inhibition of CaV channels impairs gastric vagal afferent activity following injury. In addition, the proposed work will benefit future studies investigating the use of ghrelin mimetics to treat gastric dysmotility associated with a broad range of conditions including SCI, diabetes mellitus, and obesity.

项目摘要 脊髓损伤（SCI）后胃肠道功能障碍是一种非常普遍的，但显著 未充分研究的并发症对SCI患者的生活质量产生负面影响。越来越多的证据 表明迷走神经活动受损是损伤后上消化道功能障碍的主要原因。在正常 在某些情况下，胃反射由迷走神经协调。迷走神经包含两种传入纤维 将感觉信息传递到中枢结构和传出纤维，这些传出纤维携带胃运动所需的运动输出。 宫缩我们实验室以前的工作已经证明，在损伤后，迷走神经传入神经明显减少， 对化学刺激的反应较低，包括肠肽ghrelin。Ghrelin是一种促食欲激素， 通常通过与生长激素结合来减少迷走神经传入活动并增加胃运动 促分泌素受体（GHSR 1a）是一种G蛋白偶联受体，沿着于迷走神经传入纤维。蜂窝 生长激素释放肽在健康和疾病状态下调节迷走神经传入活动的机制 还没有完全阐明。该建议将利用脊髓损伤的动物模型结合分子和 成像技术，体外膜片钳电生理学和体内神经记录，以确定机制 导致脊髓损伤后迷走神经敏感性丧失拟议的实验将调查中央 GHSR 1a介导的钙电流抑制在胃投射结节中失调的假说 脊髓损伤后的神经节细胞。根据我们的初步观察，我们将用两个具体的假设来检验这一假设。 目标。目的1将确定GHSR 1a调节电压门控Ca 2+的确切机制 通道（CaV2.2或N型）在未处理大鼠胃投射迷走神经传入神经元的全细胞贴片， 钳夹电生理学目的2将利用免疫组化，单细胞定量逆转录 聚合酶链反应（qRT-PCR）、电生理技术和体内神经记录，以鉴定 GHSR 1a介导的ghrelin对N型Ca 2+通道电流和胃迷走神经传入的影响 兴奋性在SCI后失调。该提案将提供有关如何改变 GPCR介导的CaV通道抑制损害损伤后胃迷走神经传入活动。此外，本发明还提供了一种方法， 这项工作将有助于未来研究ghrelin模拟物治疗胃动力障碍的研究。 与包括SCI、糖尿病和肥胖症在内的广泛病症相关。