DEVELOPMENT OF NEURONS IN THE GUT

肠道需要内在神经元的存在，以便运动 并发生吸收/分泌。 内在或肠神经元 从神经嵴细胞发展出来，这些细胞离开神经管， 直觉 在肠道内，这些嵴细胞迁移、聚集、增殖， 并分化成神经元，形成调节 肠蠕动 本研究的长期目标是阐明 调节肠神经系统形成的机制。 神经嵴细胞沿着肠道的位置对消化道的发育至关重要。 神经元和肠道运动的后续发展。 波峰失效 细胞占据肠道区域导致运动障碍。 先天性 巨结肠（先天性巨结肠）是由于结肠嵴缺失而引起的 终末肠细胞和假性梗阻可能是由于 中肠或后肠的嵴细胞数量有限或不足。 嵴细胞从神经轴的两个层面进入肠道： （迷走神经嵴）和骶神经管（骶神经嵴）。 迷走神经嵴细胞进入前肠，并向尾侧迁移至 后肠，而骶嵴细胞进入后肠和移动 吻部到中肠 嵴细胞沿着肠的分布取决于许多 因素 本提案的目标是评估这些因素 系统地：嵴细胞来自哪里，它们从哪里进入 肠道，它们在肠道中的位置，以及它们在肠道中形成的东西。 嵴 细胞将通过注射不能复制的逆转录病毒来标记 其携带Lac Z基因并将被组织化学检测。 逆转录病毒注射联合免疫组化检测神经元凋亡 将使用标记物来确定骶嵴对 后肠的肠神经系统。 迷走神经的作用 后肠的脊将通过手术消融骶骨来确定 冠。 为了深入了解细胞迁移的控制， 迷走嵴细胞沿着肠道的分布将用 关于它们在神经轴中的起源。 的降低效果 将通过消融评估进入肠道的迷走神经嵴的数量 迷走神经嵴的部分，并确定肠的长度 神经支配 迷走神经在迷走神经移行中的作用 脊将通过迷走神经的消融来确定。 了解 迁移过程中，活嵴细胞的运动行为将 被表征为它们在肠道中原位移动。 为此将 用荧光亲脂性活体染料DiI标记细胞， 用荧光显微镜跟踪它们的运动， 相机

The gut requires the presence of intrinsic neurons in order for motility and absorption/secretion to occur. The intrinsic or enteric neurons develop from neural crest cells that leave the neural tube and enter the gut. Within the gut these crest cells migrate, aggregate, proliferate, and differentiate into neurons which form the circuitry that regulates gut motility. The long-term objective of this study is to elucidate the mechanisms which regulate the formation of the enteric nervous system. The placement of the neural crest cells along the gut is critical to the subsequent development of neurons and gut motility. Failure of crest cells to occupy regions of gut results in motility disorders. Congenital megacolon (Hirschsprung's disease) results from the absence of crest cells in the terminal bowel and pseudoobstruction may result from a marginal or inadequate number of crest cells in the midgut or hindgut. Crest cells enter the gut from two levels of the neuroaxis: the hindbrain (vagal neural crest) and the sacral neural tube (sacral neural crest). Vagal neural crest cells enter the foregut and migrate caudally to the hindgut, while the sacral crest cells enter the hindgut and move rostrally to the midgut. The disposition of the crest cells along the gut depends on a number of factors. The objectives of this proposal are to evaluate these factors systematically: where the crest cells come from, where they enter the gut, where they go in the gut, and what they form in the gut. Crest cells will be marked by injection of a replication-incompetent retrovirus which carries the Lac Z gene and will be detected histochemically. Injection of retrovirus in combination with immunostaining for neural markers will be used to establish the contribution of the sacral crest to the enteric nervous system in the hindgut. The contribution of the vagal crest to the hindgut will be determined by surgically ablating the sacral crest. To gain insight into the control of cell migration, the distribution of vagal crest cells along the gut will be mapped with respect to their origin in the neuroaxis. The effect of reducing the number of vagal crest entering the gut will be evaluated by ablating portions of the vagal crest, and determining the length of gut innervated. The role of the vagus nerve in the immigration of vagal crest will be determined by ablation of the vagus nerve. To learn about the process of migration, the motile behavior of living crest cells will be characterized as they move in situ through the gut. This will be done by labeling cells with the fluorescent lipophilic vital dye DiI, and following their movements with a fluorescent microscope and sensitive camera.