REFLEX PATHWAYS IN THE CONTROL OF INTESTINAL MOTILITY

控制肠蠕动的反射途径

• 批准号: 2144922
• 负责人: Terence Keith Smith
• 金额: $ 3.75万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-28 至 1995-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2144922
• 关键词: chemical stimulation; gastrointestinal motility /pressure; guinea pigs; hydrochloric acid; interneurons; intestinal mucosa; intestine surgery; microelectrodes; motor neurons; myenteric plexus; neuroanatomy; neurons; single cell analysis; smooth muscle; somatic reflex

The normal motility patterns of the gastrointestinal tract are largely dependent on intrinsic nervous reflexes. Pathological changes in these enteric neurons underly many motility disorders. Our progress in understanding how movements of the gastrointestinal tract are controlled has been considerably hampered by our lack of understanding of the nerve circuits involved. The experiments outlined in this proposal are designed to address this deficiency. This study will determine the intrinsic neuronal circuitry underlying motility reflexes in the ileum, proximal colon and distal colon of the guinea pig. Intracellular recording techniques will be used to correlate reflex responses of enteric neurons to distension, mechanical brushing of the mucosa and chemical stimulation (Hcl) of the mucosa with responses in longitudinal and circular smooth muscle cells to similar stimuli. A novel preparation consisting of an opened segment of intestine pinned with the mucosa uppermost over 1 or 2 balloons has been designed to facilitate intracellular recordings from both enteric neurons and smooth muscle cells. This preparation allows any of the above stimuli to be applied separately or interacted at areas oral and anal and even circumferential to the recording site. Once the response of an impaled neuron to one or each of the stimuli has been determined it will be injected with a dye through the recording microelectrode. The projections of the neuron through the myenteric plexus or to either muscle layer will then be traced, and the neuron functionally identified as either a sensory, interneuron or motor neuron in a particular nervous reflex pathway or as a neuron common to several reflex pathways. In the intestine motility would be expected to result from the summation of reflexes activated by mechanical and chemical stimulation of the mucosal villi as well as by distension of the lumen. The contribution of the mucosa to distension reflexes, and interactions between reflex pathways initiated by the three stimuli will be investigated. By comparing the derived circuitry in these three functionally different regions of the gastrointestinal tract some crucial principles of enteric organizations will be determined.

胃肠道的正常运动模式主要是 依赖于内在的神经反射这些病理变化 肠神经元是许多运动障碍的基础。我们的进展 了解胃肠道的运动是如何被控制的 由于我们缺乏对神经的了解， 涉及的电路。该提案中概述的实验是 旨在弥补这一缺陷。这项研究将确定 回肠中运动反射的内在神经元回路， 豚鼠的近端结肠和远端结肠。细胞内 记录技术将被用来关联反射反应， 肠神经元扩张，机械刷粘膜， 粘膜的化学刺激（Hcl），纵向响应 和环形平滑肌细胞对类似刺激的反应。新的制备 由一段被粘膜固定住的打开的肠组成 最上面超过1或2个气球的设计， 来自肠神经元和平滑肌的细胞内记录 细胞这种准备允许施加上述任何刺激 在口腔和肛门甚至周围区域单独或相互作用 到录音现场一旦一个被刺穿的神经元对一个或 每种刺激物都被注入了一种染料 通过记录微电极。神经元的投射 通过肌间神经丛或到任一肌肉层， 追踪，神经元在功能上被鉴定为感觉， 中间神经元或运动神经元，或作为 几种反射途径共有的神经元。在肠蠕动中 会被认为是由 粘膜绒毛的机械和化学刺激以及 管腔扩张。粘膜对扩张的贡献 反射，和反射途径之间的相互作用发起的 将研究三种刺激。通过比较衍生电路 在胃肠的这三个功能不同的区域 肠道组织的一些重要原则将被 测定